Direct contact of a cell with a neighboring cell. Most such junctions are too small to be resolved by light microscopy, but they can be visualized by conventional or freeze-fracture electron microscopy, both of which show that the interacting CELL MEMBRANE and often the underlying CYTOPLASM and the intervening EXTRACELLULAR SPACE are highly specialized in these regions. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p792)
Cell-cell junctions that seal adjacent epithelial cells together, preventing the passage of most dissolved molecules from one side of the epithelial sheet to the other. (Alberts et al., Molecular Biology of the Cell, 2nd ed, p22)
A type of junction that attaches one cell to its neighbor. One of a number of differentiated regions which occur, for example, where the cytoplasmic membranes of adjacent epithelial cells are closely apposed. It consists of a circular region of each membrane together with associated intracellular microfilaments and an intercellular material which may include, for example, mucopolysaccharides. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990; Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Anchoring points where the CYTOSKELETON of neighboring cells are connected to each other. They are composed of specialized areas of the plasma membrane where bundles of the ACTIN CYTOSKELETON attach to the membrane through the transmembrane linkers, CADHERINS, which in turn attach through their extracellular domains to cadherins in the neighboring cell membranes. In sheets of cells, they form into adhesion belts (zonula adherens) that go all the way around a cell.
Connections between cells which allow passage of small molecules and electric current. Gap junctions were first described anatomically as regions of close apposition between cells with a narrow (1-2 nm) gap between cell membranes. The variety in the properties of gap junctions is reflected in the number of CONNEXINS, the family of proteins which form the junctions.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
A 195-kDa zonula occludens protein that is distinguished by the presence of a ZU5 domain at the C-terminal of the molecule.
A family of membrane glycoproteins localized to TIGHT JUNCTIONS that contain two extracellular Ig-like domains, a single transmembrane segment, and a cytoplasmic tail of variable length.
Desmoplakins are cytoskeletal linker proteins that anchor INTERMEDIATE FILAMENTS to the PLASMA MEMBRANE at DESMOSOMES.
Calcium-dependent cell adhesion proteins. They are important in the formation of ADHERENS JUNCTIONS between cells. Cadherins are classified by their distinct immunological and tissue specificities, either by letters (E- for epithelial, N- for neural, and P- for placental cadherins) or by numbers (cadherin-12 or N-cadherin 2 for brain-cadherin). Cadherins promote cell adhesion via a homophilic mechanism as in the construction of tissues and of the whole animal body.
A MARVEL domain protein that plays an important role in the formation and regulation of the TIGHT JUNCTION paracellular permeability barrier.
A CALCIUM-dependent adhesion molecule of DESMOSOMES that also plays a role in embryonic STEM CELL proliferation.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.
An integral membrane protein that is localized to TIGHT JUNCTIONS, where it plays a role in controlling the paracellular permeability of polarized cells. Mutations in the gene for claudin-1 are associated with Neonatal Ichthyosis-Sclerosing Cholangitis (NISCH) Syndrome.
A group of desmosomal cadherins with cytoplasmic tails that are divergent from those of classical CADHERINS. Their intracytoplasmic domains bind PLAKOGLOBIN; PLAKOPHILINS; and DESMOPLAKINS.
A multi-functional catenin that is highly homologous to BETA CATENIN. Gamma catenin binds CADHERINS and helps link their cytoplasmic tails to ACTIN in the CYTOSKELETON via ALPHA CATENIN. It is also found in DESMOSOMES where it mediates the link between DESMOSOMAL CADHERINS and DESMOPLAKIN.
Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.
Members of the armadillo family of proteins that are found in DESMOSOMES and interact with various proteins including desmocadherins; DESMOPLAKIN; ACTIN FILAMENTS; and KERATINS.
The synapse between a neuron and a muscle.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
A group of desmosomal cadherins with cytoplasmic tails that resemble those of classical CADHERINS.
A 43-kDa peptide which is a member of the connexin family of gap junction proteins. Connexin 43 is a product of a gene in the alpha class of connexin genes (the alpha-1 gene). It was first isolated from mammalian heart, but is widespread in the body including the brain.
A layer of epithelium that lines the heart, blood vessels (ENDOTHELIUM, VASCULAR), lymph vessels (ENDOTHELIUM, LYMPHATIC), and the serous cavities of the body.
Any of several ways in which living cells of an organism communicate with one another, whether by direct contact between cells or by means of chemical signals carried by neurotransmitter substances, hormones, and cyclic AMP.
Major constituent of the cytoskeleton found in the cytoplasm of eukaryotic cells. They form a flexible framework for the cell, provide attachment points for organelles and formed bodies, and make communication between parts of the cell possible.
Adherence of cells to surfaces or to other cells.
Surface ligands, usually glycoproteins, that mediate cell-to-cell adhesion. Their functions include the assembly and interconnection of various vertebrate systems, as well as maintenance of tissue integration, wound healing, morphogenic movements, cellular migrations, and metastasis.
A group of homologous proteins which form the intermembrane channels of GAP JUNCTIONS. The connexins are the products of an identified gene family which has both highly conserved and highly divergent regions. The variety contributes to the wide range of functional properties of gap junctions.
A single-pass transmembrane glycoproteins that mediate CALCIUM-dependent CELL ADHESION and are core components of DESMOSOMES.
A family of cytoskeletal proteins that play essential roles in CELL ADHESION at ADHERENS JUNCTIONS by linking CADHERINS to the ACTIN FILAMENTS of the CYTOSKELETON.
A zonula occludens protein subtype found in epithelial cell junctions. Several isoforms of zonula occludens-2 protein exist due to use of alternative promoter regions and alternative mRNA splicings.
The resistance to the flow of either alternating or direct electrical current.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
Phosphoproteins are proteins that have been post-translationally modified with the addition of a phosphate group, usually on serine, threonine or tyrosine residues, which can play a role in their regulation, function, interaction with other molecules, and localization within the cell.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
The minute vessels that connect the arterioles and venules.
A catenin that binds F-ACTIN and links the CYTOSKELETON with BETA CATENIN and GAMMA CATENIN.
A multi-functional catenin that participates in CELL ADHESION and nuclear signaling. Beta catenin binds CADHERINS and helps link their cytoplasmic tails to the ACTIN in the CYTOSKELETON via ALPHA CATENIN. It also serves as a transcriptional co-activator and downstream component of WNT PROTEIN-mediated SIGNAL TRANSDUCTION PATHWAYS.
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
Human colonic ADENOCARCINOMA cells that are able to express differentiation features characteristic of mature intestinal cells, such as ENTEROCYTES. These cells are valuable in vitro tools for studies related to intestinal cell function and differentiation.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
The property of blood capillary ENDOTHELIUM that allows for the selective exchange of substances between the blood and surrounding tissues and through membranous barriers such as the BLOOD-AIR BARRIER; BLOOD-AQUEOUS BARRIER; BLOOD-BRAIN BARRIER; BLOOD-NERVE BARRIER; BLOOD-RETINAL BARRIER; and BLOOD-TESTIS BARRIER. Small lipid-soluble molecules such as carbon dioxide and oxygen move freely by diffusion. Water and water-soluble molecules cannot pass through the endothelial walls and are dependent on microscopic pores. These pores show narrow areas (TIGHT JUNCTIONS) which may limit large molecule movement.
Established cell cultures that have the potential to propagate indefinitely.
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
A transparent, biconvex structure of the EYE, enclosed in a capsule and situated behind the IRIS and in front of the vitreous humor (VITREOUS BODY). It is slightly overlapped at its margin by the ciliary processes. Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
A form of interference microscopy in which variations of the refracting index in the object are converted into variations of intensity in the image. This is achieved by the action of a phase plate.
Lanthanum. The prototypical element in the rare earth family of metals. It has the atomic symbol La, atomic number 57, and atomic weight 138.91. Lanthanide ion is used in experimental biology as a calcium antagonist; lanthanum oxide improves the optical properties of glass.
Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.
Highly differentiated epithelial cells of the visceral layer of BOWMAN CAPSULE of the KIDNEY. They are composed of a cell body with major CELL SURFACE EXTENSIONS and secondary fingerlike extensions called pedicels. They enwrap the KIDNEY GLOMERULUS capillaries with their cell surface extensions forming a filtration structure. The pedicels of neighboring podocytes interdigitate with each other leaving between them filtration slits that are bridged by an extracellular structure impermeable to large macromolecules called the slit diaphragm, and provide the last barrier to protein loss in the KIDNEY.
A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
A large family of MONOMERIC GTP-BINDING PROTEINS that are involved in regulation of actin organization, gene expression and cell cycle progression. This enzyme was formerly listed as EC 3.6.1.47.
Highly specialized EPITHELIAL CELLS that line the HEART; BLOOD VESSELS; and lymph vessels, forming the ENDOTHELIUM. They are polygonal in shape and joined together by TIGHT JUNCTIONS. The tight junctions allow for variable permeability to specific macromolecules that are transported across the endothelial layer.
The area covering the terminal portion of ESOPHAGUS and the beginning of STOMACH at the cardiac orifice.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.
Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.
The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.
Proteins that take part in the formation or structure of TIGHT JUNCTIONS.
Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.
A sub-family of RHO GTP-BINDING PROTEINS that is involved in regulating the organization of cytoskeletal filaments. This enzyme was formerly listed as EC 3.6.1.47.
Enzymes that recognize CRUCIFORM DNA structures and introduce paired incisions that help to resolve the structure into two DNA helices.
Cell adhesion molecules present on virtually all monocytes, platelets, and granulocytes. CD31 is highly expressed on endothelial cells and concentrated at the junctions between them.
Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The ability of a substrate to allow the passage of ELECTRONS.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.
The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
Elements of limited time intervals, contributing to particular results or situations.
Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
Venous vessels in the umbilical cord. They carry oxygenated, nutrient-rich blood from the mother to the FETUS via the PLACENTA. In humans, there is normally one umbilical vein.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
A cross-shaped DNA structure that can be observed under the electron microscope. It is formed by the incomplete exchange of strands between two double-stranded helices or by complementary INVERTED REPEAT SEQUENCES that refold into hairpin loops on opposite strands across from each other.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
Antibodies produced by a single clone of cells.
Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.

Freeze-fracture studies of frog atrial fibres. (1/2154)

The freeze-fracturing technique was used to characterize the junctional devices involved in the electrical coupling of frog atrial fibres. These fibres are connected by a type of junction which can be interpreted as a morphological variant of the "gap junction" or "nexus". The most characteristic features are rows of 9-nm junctional particles forming single or anastomosed circular profiles on the inner membrane face, and corresponding pits on the outer membrane face. Very seldom aggregates consisting of few geometrically disposed 9-nm particles are found. The significance of the junctional structures in the atrial fibres is discussed, with respect to present knowledge about junctional features of gap junctions in various tissues, including embryonic ones.  (+info)

Cell junctions in the developing compound eye of the desert locust Schistocerca gregaria. (2/2154)

Intercellular junctions in the developing retina of the locust Schistocerca gregaria have been examined by electron microscopy. Different types of junction appear in a well defined sequence during development. Five stages of ommatidial development are described. Close junctions and punctate junctions are present throughout development. Gap junctions appear transiently amongst the undifferentiated cells, before clearly defined preommatidia can be distinguished. The subsequent disappearance of gap junctions may be correlated with cell determination. Lanthanum studies confirm these findings. The later sequential appearance of adhesive junction types is described. These include septate desmosomes and two types of desmosomes. In the fully differentiated ommatidium only two types of junction remain, these are: desmosomes and rhabdomeric junctions.  (+info)

PETA-3/CD151, a member of the transmembrane 4 superfamily, is localised to the plasma membrane and endocytic system of endothelial cells, associates with multiple integrins and modulates cell function. (3/2154)

The Transmembrane 4 Superfamily member, PETA-3/CD151, is ubiquitously expressed by endothelial cells in vivo. In cultured human umbilical vein endothelial cells PETA-3 is present on the plasma membrane and predominantly localises to regions of cell-cell contact. Additionally, this protein is abundant within an intracellular compartment which accounts for up to 66% of the total PETA-3 expressed. Intracellular PETA-3 showed colocalisation with transferrin receptor and CD63 suggesting an endosomal/lysosomal localisation which was supported by immuno-electronmicroscopy studies. Co-immunoprecipitation experiments investigating possible interactions of PETA-3 with other molecules demonstrated associations with several integrin chains including beta1, beta3, beta4, (alpha)2, (alpha)3, (alpha)5, (alpha)6 and provide the first report of Transmembrane 4 Superfamily association with the (alpha)6beta4 integrin. Using 2-colour confocal microscopy, we demonstrated similar localisation of PETA-3 and integrin chains within cytoplasmic vesicles and endothelial cell junctions. In order to assess the functional implications of PETA-3/integrin associations, the effect of anti-PETA-3 antibodies on endothelial function was examined. Anti-PETA-3 mAb inhibited endothelial cell migration and modulated in vitro angiogenesis, but had no detectable effect on neutrophil transendothelial migration. The broad range of integrin associations and the presence of PETA-3 with integrins both on the plasma membrane and within intracellular vesicles, suggests a primary role for PETA-3 in regulating integrin trafficking and/or function.  (+info)

Intercellular junctions in the ciliary epithelium. (4/2154)

The fine structure of the intercellular junctions in the ciliary epithelium of rhesus monkeys and rabbits was studied with conventional electron microscopy of thin-sectioned specimens and the freeze-fracturing technique. In the rhesus monkey, a zonula occludens, zonula adhaerens, gap junctions, and desmosomes interconnect the nonpigmented cells, whereas gap junctions, puncta adhaerentia, and desmosomes connect pigmented to nonpigmented cells, and pigmented cells to one another. In the rabbit, desmosomes are absent between nonpigmented cells, and substituted for by puncta adhaerentia. The zonula occludens between nonpigmented cells greatly varies in its complexity in different regions of the cell perimeter, and in places, it may consist of very few intramembrane strands; this suggests that the ciliary epithelium is relatively leaky to ions and small molecules. Gap junctions are ubiquitous in the ciliary epithelium and particularly numerous at the interface between pigmented and nonpigmented layers; this finding indicates that the cells of the ciliary epithelium are joined in a metabolic syncytium. All gap junctions are characterized by the crystalline configuration which is typical of the uncoupled state; furthermore, in specimens fixed by immersion, they may be caused by uncoupling and take place in the time interval elapsing between interruption of the blood supply and arrival of the fixative fluid. Puncta adhaerentia resemble zonulae adhaerentes in their structural details but are macular in shape instead of encompassing the cell perimeter in a beltlike fashion. In contrast with desmosomes, the intercellular cleft of puncta adhaerentia has an irregular width and contains opaque material, but this never gives rise to the central band typical of desmosomes. On the inner aspect of the junctional membranes, there is a layer of fluffy material but no plaque of insertion for a bundle of tonofilaments. Finally, puncta adhaerentia have no representation in the interior of the plasmalemma and are intimately associated with cytoplasmic microfilaments. They probably anchor to the plasmalemma the contractile apparatus of the ciliary epithelial cells.  (+info)

Facilitation and depression of ATP and noradrenaline release from sympathetic nerves of rat tail artery. (5/2154)

1. Excitatory junction currents (EJCs) were used to measure ATP release; noradrenaline (NA) oxidation currents and fractional overflow of labelled NA, [3H]NA, were used to monitor the release of endogenous and exogenous NA, respectively, from post-ganglionic sympathetic nerves of rat tail artery. 2. During nerve stimulation with 100 pulses at 5-20 Hz the EJCs initially grew in size (maximally by 23 %, at 2-10 Hz), and then depressed, maximally by 68 % at 20 Hz. 3. The peak amplitude of NA oxidation currents in response to nerve stimulation with 100 pulses at 2-20 Hz grew in size with frequency, while the area was independent of frequency and roughly constant. 4. The size of the NA oxidation currents evoked by nerve stimulation with 4-100 pulses at 20 Hz grew linearly with train length between pulses 4-16. Between pulses 20-100 there was a train length-dependent depression of the signal. 5. Fractional overflow of [3H]NA in response to nerve stimulation with 5-100 pulses at 20 Hz behaved similarly to the EJCs. It initially grew roughly linearly between pulses 5-25, and then showed a dramatic depression similar to that of the EJCs. 6. The alpha2-adrenoceptor antagonists rauwolscine and yohimbine increased the overflow of [3H]NA and the amplitude of NA oxidation currents, but not that of the EJCs. 7. It is concluded that during high-frequency stimulation (i) the release of ATP and NA is first briefly facilitated then markedly depressed, (ii) facilitation and depression of the two transmitters are similar in magnitude and time course, and (iii) alpha2-adrenoceptor antagonists differentially modify EJCs and the NA signals. The results obtained in the absence of drugs are compatible with the hypothesis that ATP and NA are released in parallel, while the effects of alpha2-adrenoceptor antagonists seem to suggest dissociated release.  (+info)

Characterization of the 4C8 antigen involved in transendothelial migration of CD26(hi) T cells after tight adhesion to human umbilical vein endothelial cell monolayers. (6/2154)

In extravasation of T cells, little is known about the mechanisms of transendothelial migration subsequent to the T cells' tight adhesion to endothelium. To investigate these mechanisms, we developed a monoclonal antibody (mAb), termed anti-4C8, that blocks transmigration but not adhesion in a culture system in which high CD26-expressing (CD26(hi)) T cells preferentially migrate through human umbilical vein endothelial cell (HUVEC) monolayers cultured on collagen gels. Anti-4C8 reacted with all CD3(+) T cells and monocytes but not neutrophils or HUVECs. The structure defined by this antibody was an 80-kD molecule. The mAb at 1 mug/ml inhibited 80-90% of migration of CD3(+) T cells through unstimulated and interferon gamma-stimulated HUVEC monolayers without interfering with adhesion and cell motility. When added to the cultures after the adhesion, anti-4C8 completely blocked subsequent transmigration of adherent T cells. Phase-contrast and electron microscopy revealed that T cells are arrested at the intercellular junctions of HUVECs in the presence of anti-4C8. Anti-4C8 exhibited agonistic effects on resting T cells without other stimuli under culture conditions in which anti-4C8 can stimulate T cells. First, in the checkerboard assay using collagen gels, the antibody promoted chemokinetic migration of the cells in a dose-dependent manner from 0.1 to 10 mug/ml. The predominant population of T cells that migrated into collagen gels with impregnated anti-4C8 were CD26(hi). Second, solid-phase-immobilized anti-4C8 induced adhesion of T cells to the substrate, often with polarizations in cell shape and large pseudopods rich in filamentous (F-) actin. Third, soluble anti-4C8 augmented F-actin content preferentially in CD26(hi) T cells when added to T cells at a high dose of 10 mug/ml. Finally, both anti-4C8-induced chemokinetic migration and transendothelial migration were inhibited by pretreatment of T cells with pertussis toxin. These findings suggest that stimulation via the 4C8 antigen increases cell motility of CD26(hi) cells with profound cytoskeletal changes through signaling pathways including G proteins. The 4C8 antigen may be involved in preferential transmigration of CD26(hi) cells adherent to HUVECs.  (+info)

Synapses involving auditory nerve fibers in primate cochlea. (7/2154)

The anatomical mechanisms for processing auditory signals are extremely complex and incompletely understood, despite major advances already made with the use of electron microscopy. A major enigma, for example, is the presence in the mammalian cochlea of a double hair cell receptor system. A renewed attempt to discover evidence of synaptic coupling between the two systems in the primate cochlea, postulated from physiological studies, has failed. However, in the outer spiral bundle the narrow and rigid clefts seen between pairs of presumptive afferent fibers suggest the possibility of dendro-dendritic interaction confined to the outer hair cell system. The clustering of afferent processes within folds of supporting cells subjacent to outer hair cells is in contrast to the lack of such close associations in the inner hair cell region. The difference reinforces the suggestion of functional interaction of some sort between the outer hair cell afferent nerve processes.  (+info)

Agonist-stimulated cytoskeletal reorganization and signal transduction at focal adhesions in vascular smooth muscle cells require c-Src. (8/2154)

Thrombin and angiotensin II (angII) have trophic properties as mediators of vascular remodeling. Focal adhesions and actin cytoskeleton are involved in cell growth, shape, and movement and may be important in vascular remodeling. To characterize mechanisms by which thrombin and angII modulate vessel structure, we studied the effects of these G protein-coupled receptor ligands on focal adhesions in vascular smooth muscle cells (VSMCs). Both thrombin and angII stimulated bundling of actin filaments to form stress fibers, assembly of focal adhesions, and protein tyrosine phosphorylation at focal adhesions, such as p130Cas, paxillin, and tensin. To test whether c-Src plays a critical role in focal adhesion rearrangement, we analyzed cells with altered c-Src activity by retroviral transduction of wild-type (WT) and kinase-inactive (KI) c-Src into rat VSMCs, and by use of VSMCs from WT (src+/+) and Src-deficient (src-/-) mice. Tyrosine phosphorylation of Cas, paxillin, and tensin were markedly decreased in VSMCs expressing KI-Src and in src-/- VSMCs. Expression of KI-Src did not inhibit stress fiber formation by thrombin. Surprisingly, actin bundling was markedly decreased in VSMCs from src-/- mice both basally and after thrombin stimulation, compared with src+/+ mice. We also studied the effect of KI-Src and WT-Src on VSMC spreading. Expression of KI-Src reduced the rate of VSMC spreading on collagen, whereas WT-Src enhanced cell spreading. In conclusion, c-Src plays a critical role in agonist-stimulated cytoskeletal reorganization and signal transduction at focal adhesions in VSMCs. c-Src kinase activity is required for the cytoskeletal turnover that occurs in cell spreading, whereas c-Src appears to regulate actin bundling via a kinase-independent mechanism.  (+info)

Intercellular junctions are specialized areas of contact between two or more adjacent cells in multicellular organisms. They play crucial roles in maintaining tissue structure and function by regulating the movement of ions, molecules, and even larger cellular structures from one cell to another. There are several types of intercellular junctions, including:

1. Tight Junctions (Zonulae Occludentes): These are the most apical structures in epithelial and endothelial cells, forming a virtually impermeable barrier to prevent the paracellular passage of solutes and water between the cells. They create a tight seal by connecting the transmembrane proteins of adjacent cells, such as occludin and claudins.
2. Adherens Junctions: These are located just below the tight junctions and help maintain cell-to-cell adhesion and tissue integrity. Adherens junctions consist of cadherin proteins that form homophilic interactions with cadherins on adjacent cells, as well as intracellular adaptor proteins like catenins, which connect to the actin cytoskeleton.
3. Desmosomes: These are another type of cell-to-cell adhesion structure, primarily found in tissues that experience mechanical stress, such as the skin and heart. Desmosomes consist of cadherin proteins (desmocadherins) that interact with each other and connect to intermediate filaments (keratin in epithelial cells) via plakoglobin and desmoplakin.
4. Gap Junctions: These are specialized channels that directly connect the cytoplasm of adjacent cells, allowing for the exchange of small molecules, ions, and second messengers. Gap junctions consist of connexin proteins that form hexameric structures called connexons in the plasma membrane of each cell. When two connexons align, they create a continuous pore or channel between the cells.

In summary, intercellular junctions are essential for maintaining tissue structure and function by regulating paracellular transport, cell-to-cell adhesion, and intercellular communication.

Tight junctions, also known as zonula occludens, are specialized types of intercellular junctions that occur in epithelial and endothelial cells. They are located near the apical side of the lateral membranes of adjacent cells, where they form a continuous belt-like structure that seals off the space between the cells.

Tight junctions are composed of several proteins, including occludin, claudins, and junctional adhesion molecules (JAMs), which interact to form a network of strands that create a tight barrier. This barrier regulates the paracellular permeability of ions, solutes, and water, preventing their uncontrolled movement across the epithelial or endothelial layer.

Tight junctions also play an important role in maintaining cell polarity by preventing the mixing of apical and basolateral membrane components. Additionally, they are involved in various signaling pathways that regulate cell proliferation, differentiation, and survival.

Desmosomes are specialized intercellular junctions that provide strong adhesion between adjacent epithelial cells and help maintain the structural integrity and stability of tissues. They are composed of several proteins, including desmoplakin, plakoglobin, and cadherins, which form complex structures that anchor intermediate filaments (such as keratin) to the cell membrane. This creates a network of interconnected cells that can withstand mechanical stresses. Desmosomes are particularly abundant in tissues subjected to high levels of tension, such as the skin and heart.

Adherens junctions are specialized types of cell-cell contacts that play a crucial role in maintaining the integrity and stability of tissues. They are composed of transmembrane cadherin proteins, which connect to the actin cytoskeleton inside the cell through intracellular adaptor proteins such as catenins.

The cadherins on opposing cells interact with each other to form adhesive bonds that help to anchor the cells together and regulate various cellular processes, including cell growth, differentiation, and migration. Adherens junctions are essential for many physiological processes, such as embryonic development, wound healing, and tissue homeostasis, and their dysfunction has been implicated in a variety of diseases, including cancer and degenerative disorders.

Gap junctions are specialized intercellular connections that allow for the direct exchange of ions, small molecules, and electrical signals between adjacent cells. They are composed of arrays of channels called connexons, which penetrate the cell membranes of two neighboring cells and create a continuous pathway for the passage of materials from one cytoplasm to the other. Each connexon is formed by the assembly of six proteins called connexins, which are encoded by different genes and vary in their biophysical properties. Gap junctions play crucial roles in many physiological processes, including the coordination of electrical activity in excitable tissues, the regulation of cell growth and differentiation, and the maintenance of tissue homeostasis. Mutations or dysfunctions in gap junction channels have been implicated in various human diseases, such as cardiovascular disorders, neurological disorders, skin disorders, and cancer.

Freeze fracturing is not a medical term itself, but it is a technique used in the field of electron microscopy, which is a type of imaging commonly used in scientific research and medical fields to visualize structures at a very small scale, such as cells and cellular components.

In freeze fracturing, a sample is rapidly frozen to preserve its structure and then fractured or split along a plane of weakness, often along the membrane of a cell. The freshly exposed surface is then shadowed with a thin layer of metal, such as platinum or gold, to create a replica of the surface. This replica can then be examined using an electron microscope to reveal details about the structure and organization of the sample at the molecular level.

Freeze fracturing is particularly useful for studying membrane structures, such as lipid bilayers and protein complexes, because it allows researchers to visualize these structures in their native state, without the need for staining or other chemical treatments that can alter or damage the samples.

Zonula Occludens-1 (ZO-1) protein is a tight junction (TJ) protein, which belongs to the membrane-associated guanylate kinase (MAGUK) family. It plays a crucial role in the formation and maintenance of tight junctions, which are complex structures that form a barrier between neighboring cells in epithelial and endothelial tissues.

Tight junctions are composed of several proteins, including transmembrane proteins and cytoplasmic plaque proteins. ZO-1 is one of the major cytoplasmic plaque proteins that interact with both transmembrane proteins (such as occludin and claudins) and other cytoskeletal proteins to form a network of protein interactions that maintain the integrity of tight junctions.

ZO-1 has multiple domains, including PDZ domains, SH3 domains, and a guanylate kinase-like domain, which allow it to interact with various binding partners. It is involved in regulating paracellular permeability, cell polarity, and signal transduction pathways that control cell proliferation, differentiation, and survival.

Mutations or dysfunction of ZO-1 protein have been implicated in several human diseases, including inflammatory bowel disease, cancer, and neurological disorders.

Junctional Adhesion Molecules (JAMs) are a group of proteins that play crucial roles in cell-cell adhesion, formation and maintenance of tight junctions, and regulation of trafficking of various molecules across the epithelial and endothelial barriers. They belong to the immunoglobulin superfamily and are typically composed of a single transmembrane domain, an extracellular domain with variable numbers of immunoglobulin-like motifs, and a cytoplasmic tail that interacts with intracellular signaling molecules.

JAMs are involved in various cellular processes, such as leukocyte migration, angiogenesis, and maintenance of epithelial polarity. Dysregulation of JAMs has been implicated in several pathological conditions, including inflammatory bowel disease, cancer, and viral infections.

Some examples of Junctional Adhesion Molecules include JAM-A, JAM-B, JAM-C, JAM-4, and coxsackievirus and adenovirus receptor (CAR). These proteins are differentially expressed in various tissues and cells, and they have distinct functions and binding partners.

Desmoplakins are important proteins that play a crucial role in the structural integrity and function of certain types of cell-to-cell junctions called desmosomes. Desmosomes are specialized structures that connect adjacent cells in tissues that undergo significant mechanical stress, such as the skin, heart, and gut.

Desmoplakins are large proteins that are composed of several domains, including a plakin domain, which interacts with other desmosomal components, and a spectrin-like repeat domain, which binds to intermediate filaments. By linking desmosomes to the intermediate filament network, desmoplakins help to provide mechanical strength and stability to tissues.

Mutations in the genes that encode desmoplakins have been associated with several human genetic disorders, including arrhythmogenic right ventricular cardiomyopathy (ARVC), a heart condition characterized by abnormal heart rhythms and structural changes in the heart muscle, and epidermolysis bullosa simplex (EBS), a skin disorder characterized by blistering and fragility of the skin.

Cadherins are a type of cell adhesion molecule that play a crucial role in the development and maintenance of intercellular junctions. They are transmembrane proteins that mediate calcium-dependent homophilic binding between adjacent cells, meaning that they bind to identical cadherin molecules on neighboring cells.

There are several types of cadherins, including classical cadherins, desmosomal cadherins, and protocadherins, each with distinct functions and localization in tissues. Classical cadherins, also known as type I cadherins, are the most well-studied and are essential for the formation of adherens junctions, which help to maintain cell-to-cell contact and tissue architecture.

Desmosomal cadherins, on the other hand, are critical for the formation and maintenance of desmosomes, which are specialized intercellular junctions that provide mechanical strength and stability to tissues. Protocadherins are a diverse family of cadherin-related proteins that have been implicated in various developmental processes, including neuronal connectivity and tissue patterning.

Mutations in cadherin genes have been associated with several human diseases, including cancer, neurological disorders, and heart defects. Therefore, understanding the structure, function, and regulation of cadherins is essential for elucidating their roles in health and disease.

Occludin is a protein that is a component of tight junctions, which are structures that form a barrier between adjacent cells in epithelial and endothelial tissues. Tight junctions help to regulate the movement of molecules between cells and play a crucial role in maintaining the integrity of these tissues.

Occludin is composed of four transmembrane domains, two extracellular loops, and intracellular N- and C-termini. The extracellular loops interact with other tight junction proteins to form the intercellular seal, while the intracellular domains interact with various signaling molecules and cytoskeletal components to regulate the assembly and disassembly of tight junctions.

Mutations in the gene that encodes occludin have been associated with various human diseases, including inflammatory bowel disease, liver cirrhosis, and skin disorders. Additionally, changes in occludin expression and localization have been implicated in the development of cancer and neurological disorders.

Desmoglein 2 is a type of desmoglein protein that is primarily found in the desmosomes of epithelial cells. Desmosomes are specialized structures that help to anchor intermediate filaments to the cell membrane and provide strength and stability to tissues that undergo mechanical stress, such as the skin and heart.

Desmoglein 2 plays a critical role in maintaining cell-cell adhesion by forming intercellular junctions called desmosomal cadherins. These junctions help to hold adjacent cells together and contribute to the integrity of epithelial tissues. Mutations in the gene that encodes Desmoglein 2 have been associated with several skin disorders, including pemphigus vulgaris, a blistering autoimmune disease that affects mucous membranes and the skin. In this condition, antibodies target Desmoglein 2, leading to loss of cell-cell adhesion and formation of blisters.

Electron microscopy (EM) is a type of microscopy that uses a beam of electrons to create an image of the sample being examined, resulting in much higher magnification and resolution than light microscopy. There are several types of electron microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and reflection electron microscopy (REM).

In TEM, a beam of electrons is transmitted through a thin slice of the sample, and the electrons that pass through the sample are focused to form an image. This technique can provide detailed information about the internal structure of cells, viruses, and other biological specimens, as well as the composition and structure of materials at the atomic level.

In SEM, a beam of electrons is scanned across the surface of the sample, and the electrons that are scattered back from the surface are detected to create an image. This technique can provide information about the topography and composition of surfaces, as well as the structure of materials at the microscopic level.

REM is a variation of SEM in which the beam of electrons is reflected off the surface of the sample, rather than scattered back from it. This technique can provide information about the surface chemistry and composition of materials.

Electron microscopy has a wide range of applications in biology, medicine, and materials science, including the study of cellular structure and function, disease diagnosis, and the development of new materials and technologies.

Epithelium is the tissue that covers the outer surface of the body, lines the internal cavities and organs, and forms various glands. It is composed of one or more layers of tightly packed cells that have a uniform shape and size, and rest on a basement membrane. Epithelial tissues are avascular, meaning they do not contain blood vessels, and are supplied with nutrients by diffusion from the underlying connective tissue.

Epithelial cells perform a variety of functions, including protection, secretion, absorption, excretion, and sensation. They can be classified based on their shape and the number of cell layers they contain. The main types of epithelium are:

1. Squamous epithelium: composed of flat, scalelike cells that fit together like tiles on a roof. It forms the lining of blood vessels, air sacs in the lungs, and the outermost layer of the skin.
2. Cuboidal epithelium: composed of cube-shaped cells with equal height and width. It is found in glands, tubules, and ducts.
3. Columnar epithelium: composed of tall, rectangular cells that are taller than they are wide. It lines the respiratory, digestive, and reproductive tracts.
4. Pseudostratified epithelium: appears stratified or layered but is actually made up of a single layer of cells that vary in height. The nuclei of these cells appear at different levels, giving the tissue a stratified appearance. It lines the respiratory and reproductive tracts.
5. Transitional epithelium: composed of several layers of cells that can stretch and change shape to accommodate changes in volume. It is found in the urinary bladder and ureters.

Epithelial tissue provides a barrier between the internal and external environments, protecting the body from physical, chemical, and biological damage. It also plays a crucial role in maintaining homeostasis by regulating the exchange of substances between the body and its environment.

Claudin-1 is a protein that is a member of the claudin family, which are important components of tight junctions in cells. Tight junctions are specialized structures that help to regulate the paracellular permeability of liquids and solutes between cells, and play a crucial role in maintaining cell polarity and tissue integrity. Claudin-1 is primarily expressed in epithelial and endothelial cells, where it helps to form tight junctions and regulate the movement of molecules across these barriers. Mutations in the gene that encodes claudin-1 have been associated with various human diseases, including skin disorders and cancer.

Desmocollins are a type of cadherin, which is a transmembrane protein involved in cell-cell adhesion. Specifically, desmocollins are found in the desmosomes, which are specialized structures that help to mechanically connect adjacent epithelial cells. There are three main isoforms of desmocollin (Desmocollin-1, -2, and -3) that are encoded by different genes. Mutations in the genes encoding desmocollins have been associated with several skin blistering disorders, including certain forms of epidermolysis bullosa.

Gamma-catenin, also known as plakoglobin, is a protein that is involved in cell adhesion and the regulation of gene expression. It is a member of the catenin family, which includes beta-catenin and alpha-catenin. Gamma-catenin is found at adherens junctions, where it interacts with cadherins to help maintain cell-cell adhesion. It also plays a role in the Wnt signaling pathway, where it can bind to TCF/LEF transcription factors and regulate the expression of target genes. Mutations in the gene that encodes gamma-catenin have been associated with several types of cancer, including colon cancer and melanoma.

Epithelial cells are types of cells that cover the outer surfaces of the body, line the inner surfaces of organs and glands, and form the lining of blood vessels and body cavities. They provide a protective barrier against the external environment, regulate the movement of materials between the internal and external environments, and are involved in the sense of touch, temperature, and pain. Epithelial cells can be squamous (flat and thin), cuboidal (square-shaped and of equal height), or columnar (tall and narrow) in shape and are classified based on their location and function.

Plakophilins are a group of proteins that play a crucial role in the structure and function of desmosomes, which are specialized cell-cell junctions found in epithelial and cardiac muscle cells. Desmosomes help to maintain the integrity and stability of tissues by providing strong adhesive connections between adjacent cells.

Plakophilins are members of the armadillo protein family and have several important functions within desmosomes:

1. Scaffolding: Plakophilins act as scaffolding proteins, helping to organize and link various components of the desmosome together. They bind to desmocollin and desmoglein adhesion molecules, as well as to other structural proteins such as plakoglobin and intermediate filaments.
2. Signal transduction: Plakophilins also play a role in signal transduction pathways related to cell growth, differentiation, and survival. They can interact with various signaling molecules, including kinases, phosphatases, and transcription factors, thereby modulating their activity.
3. Regulation of desmosome assembly and disassembly: Plakophilins are involved in the regulation of desmosome formation and breakdown. They can bind to proteins that promote desmosome assembly or disassembly, depending on cellular conditions and requirements.

There are four main isoforms of plakophilin (PKP1-4) in humans, each with distinct expression patterns and functions. Mutations in the genes encoding plakophilins have been associated with various genetic disorders, including arrhythmogenic right ventricular cardiomyopathy (ARVC), ectodermal dysplasia-syndactyly syndrome (EDSS), and skin fragility-woolly hair syndrome (SFWHS).

The neuromuscular junction (NMJ) is the specialized synapse or chemical communication point, where the motor neuron's nerve terminal (presynaptic element) meets the muscle fiber's motor end plate (postsynaptic element). This junction plays a crucial role in controlling muscle contraction and relaxation.

At the NMJ, the neurotransmitter acetylcholine is released from the presynaptic nerve terminal into the synaptic cleft, following an action potential. Acetylcholine then binds to nicotinic acetylcholine receptors on the postsynaptic membrane of the muscle fiber, leading to the generation of an end-plate potential. If sufficient end-plate potentials are generated and summate, they will trigger an action potential in the muscle fiber, ultimately causing muscle contraction.

Dysfunction at the neuromuscular junction can result in various neuromuscular disorders, such as myasthenia gravis, where autoantibodies attack acetylcholine receptors, leading to muscle weakness and fatigue.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Desmogleins are a group of proteins that are part of the desmosomes, which are structures that help to strengthen and maintain the integrity of epithelial tissues. Desmogleins play a crucial role in cell-to-cell adhesion by forming intercellular junctions known as desmoglein adherens junctions. These junctions help to anchor intermediate filaments, such as keratin, to the plasma membrane and provide structural support to epithelial cells.

There are four main types of desmogleins (Dsg1-4), each with distinct expression patterns in different tissues. For example, Dsg1 is primarily expressed in the upper layers of the epidermis, while Dsg3 is found in the lower layers and in mucous membranes. Mutations in desmoglein genes have been associated with several skin disorders, including pemphigus vulgaris and pemphigus foliaceus, which are autoimmune blistering diseases characterized by the loss of cell-to-cell adhesion in the epidermis.

Connexin 43 is a protein that forms gap junctions, which are specialized channels that allow for the direct communication and transport of small molecules between adjacent cells. Connexin 43 is widely expressed in many tissues, including the heart, brain, and various types of epithelial and connective tissues. In the heart, connexin 43 plays a crucial role in electrical conduction and coordination of contraction between cardiac muscle cells. Mutations in the gene that encodes connexin 43 have been associated with several human diseases, including certain types of cardiac arrhythmias and skin disorders.

The endothelium is the thin, delicate tissue that lines the interior surface of blood vessels and lymphatic vessels. It is a single layer of cells called endothelial cells that are in contact with the blood or lymph fluid. The endothelium plays an essential role in maintaining vascular homeostasis by regulating blood flow, coagulation, platelet activation, immune function, and angiogenesis (the formation of new blood vessels). It also acts as a barrier between the vessel wall and the circulating blood or lymph fluid. Dysfunction of the endothelium has been implicated in various cardiovascular diseases, diabetes, inflammation, and cancer.

Cell communication, also known as cell signaling, is the process by which cells exchange and transmit signals between each other and their environment. This complex system allows cells to coordinate their functions and maintain tissue homeostasis. Cell communication can occur through various mechanisms including:

1. Autocrine signaling: When a cell releases a signal that binds to receptors on the same cell, leading to changes in its behavior or function.
2. Paracrine signaling: When a cell releases a signal that binds to receptors on nearby cells, influencing their behavior or function.
3. Endocrine signaling: When a cell releases a hormone into the bloodstream, which then travels to distant target cells and binds to specific receptors, triggering a response.
4. Synaptic signaling: In neurons, communication occurs through the release of neurotransmitters that cross the synapse and bind to receptors on the postsynaptic cell, transmitting electrical or chemical signals.
5. Contact-dependent signaling: When cells physically interact with each other, allowing for the direct exchange of signals and information.

Cell communication is essential for various physiological processes such as growth, development, differentiation, metabolism, immune response, and tissue repair. Dysregulation in cell communication can contribute to diseases, including cancer, diabetes, and neurological disorders.

Cytoskeletal proteins are a type of structural proteins that form the cytoskeleton, which is the internal framework of cells. The cytoskeleton provides shape, support, and structure to the cell, and plays important roles in cell division, intracellular transport, and maintenance of cell shape and integrity.

There are three main types of cytoskeletal proteins: actin filaments, intermediate filaments, and microtubules. Actin filaments are thin, rod-like structures that are involved in muscle contraction, cell motility, and cell division. Intermediate filaments are thicker than actin filaments and provide structural support to the cell. Microtubules are hollow tubes that are involved in intracellular transport, cell division, and maintenance of cell shape.

Cytoskeletal proteins are composed of different subunits that polymerize to form filamentous structures. These proteins can be dynamically assembled and disassembled, allowing cells to change their shape and move. Mutations in cytoskeletal proteins have been linked to various human diseases, including cancer, neurological disorders, and muscular dystrophies.

Cell adhesion refers to the binding of cells to extracellular matrices or to other cells, a process that is fundamental to the development, function, and maintenance of multicellular organisms. Cell adhesion is mediated by various cell surface receptors, such as integrins, cadherins, and immunoglobulin-like cell adhesion molecules (Ig-CAMs), which interact with specific ligands in the extracellular environment. These interactions lead to the formation of specialized junctions, such as tight junctions, adherens junctions, and desmosomes, that help to maintain tissue architecture and regulate various cellular processes, including proliferation, differentiation, migration, and survival. Disruptions in cell adhesion can contribute to a variety of diseases, including cancer, inflammation, and degenerative disorders.

Cell adhesion molecules (CAMs) are a type of protein found on the surface of cells that mediate the attachment or adhesion of cells to either other cells or to the extracellular matrix (ECM), which is the network of proteins and carbohydrates that provides structural and biochemical support to surrounding cells.

CAMs play crucial roles in various biological processes, including tissue development, differentiation, repair, and maintenance of tissue architecture and function. They are also involved in cell signaling, migration, and regulation of the immune response.

There are several types of CAMs, classified based on their structure and function, such as immunoglobulin-like CAMs (IgCAMs), cadherins, integrins, and selectins. Dysregulation of CAMs has been implicated in various diseases, including cancer, inflammation, and neurological disorders.

Connexins are a family of proteins that form the structural units of gap junctions, which are specialized channels that allow for the direct exchange of small molecules and ions between adjacent cells. These channels play crucial roles in maintaining tissue homeostasis, coordinating cellular activities, and enabling communication between cells. In humans, there are 21 different connexin genes that encode for these proteins, with each isoform having unique properties and distributions within the body. Mutations in connexin genes have been linked to a variety of human diseases, including hearing loss, skin disorders, and heart conditions.

Desmosomal cadherins, also known as desmocadherins, are a subfamily of the cadherin superfamily of calcium-dependent adhesion molecules. They are primarily responsible for cell-cell adhesion in tissues that undergo mechanical stress, such as epithelial and cardiac tissue.

Desmosomal cadherins include desmocadherin-1 (Desmoglein-1) and desmocadherin-2 (Desmocollin-2), which are located in the desmosomes of adjacent cells. Desmosomes are specialized intercellular junctions that provide strong adhesion and help maintain tissue integrity during mechanical stress.

Desmosomal cadherins have a unique structure, with an extracellular domain containing multiple cadherin repeats that mediate homophilic interactions between adjacent cells. They also have a cytoplasmic domain that interacts with desmoplakin, a protein that links the desmosomal cadherins to the intermediate filament cytoskeleton.

Mutations in desmosomal cadherins have been associated with several human genetic disorders, including skin blistering diseases and arrhythmogenic right ventricular cardiomyopathy (ARVC), a heart condition that can lead to sudden cardiac death.

Catenins are a type of protein that play a crucial role in cell adhesion and signal transduction. They are named for their ability to link together (or "catenate") proteins called cadherins, which are important for the formation of tight junctions between cells. Catenins help to anchor cadherins to the cytoskeleton, providing structural support and stability to tissues.

There are several different types of catenins, including alpha-catenin, beta-catenin, gamma-catenin (also called plakoglobin), and delta-catenin. Alpha-catenin links cadherins to the actin cytoskeleton, while beta-catenin and gamma-catenin can also interact with transcription factors in the nucleus to regulate gene expression.

Mutations in catenin genes have been associated with various human diseases, including cancer. For example, abnormal activation of the Wnt signaling pathway, which involves beta-catenin, has been implicated in several types of cancer. Additionally, mutations in alpha-E-catenin, a type of alpha-catenin found in epithelial cells, have been linked to colorectal cancer.

Zonula Occludens-2 (ZO-2) protein is a tight junction protein, which belongs to the membrane-associated guanylate kinase homologs (MAGUKs) family. It plays a crucial role in the formation and maintenance of tight junctions, which are complex structures that form a barrier between neighboring cells in epithelial and endothelial tissues.

ZO-2 protein is localized to the cytoplasmic face of the tight junction and interacts with various proteins, including transmembrane proteins such as occludin and claudins, as well as other cytoskeletal proteins. It contains several functional domains that enable it to interact with these proteins, including PDZ (PSD-95/Dlg/ZO-1) domains, SH3 (Src homology 3) domains, and a guanylate kinase-like domain.

ZO-2 protein has been implicated in various cellular processes, including the regulation of tight junction permeability, cell signaling, and gene expression. Mutations in ZO-2 have been associated with several human diseases, including inflammatory bowel disease, cancer, and neurological disorders.

Electric impedance is a measure of opposition to the flow of alternating current (AC) in an electrical circuit or component, caused by both resistance (ohmic) and reactance (capacitive and inductive). It is expressed as a complex number, with the real part representing resistance and the imaginary part representing reactance. The unit of electric impedance is the ohm (Ω).

In the context of medical devices, electric impedance may be used to measure various physiological parameters, such as tissue conductivity or fluid composition. For example, bioelectrical impedance analysis (BIA) uses electrical impedance to estimate body composition, including fat mass and lean muscle mass. Similarly, electrical impedance tomography (EIT) is a medical imaging technique that uses electric impedance to create images of internal organs and tissues.

Cell membrane permeability refers to the ability of various substances, such as molecules and ions, to pass through the cell membrane. The cell membrane, also known as the plasma membrane, is a thin, flexible barrier that surrounds all cells, controlling what enters and leaves the cell. Its primary function is to protect the cell's internal environment and maintain homeostasis.

The permeability of the cell membrane depends on its structure, which consists of a phospholipid bilayer interspersed with proteins. The hydrophilic (water-loving) heads of the phospholipids face outward, while the hydrophobic (water-fearing) tails face inward, creating a barrier that is generally impermeable to large, polar, or charged molecules.

However, specific proteins within the membrane, called channels and transporters, allow certain substances to cross the membrane. Channels are protein structures that span the membrane and provide a pore for ions or small uncharged molecules to pass through. Transporters, on the other hand, are proteins that bind to specific molecules and facilitate their movement across the membrane, often using energy in the form of ATP.

The permeability of the cell membrane can be influenced by various factors, such as temperature, pH, and the presence of certain chemicals or drugs. Changes in permeability can have significant consequences for the cell's function and survival, as they can disrupt ion balances, nutrient uptake, waste removal, and signal transduction.

I believe there might be a misunderstanding in your question. "Dogs" is not a medical term or condition. It is the common name for a domesticated carnivore of the family Canidae, specifically the genus Canis, which includes wolves, foxes, and other extant and extinct species of mammals. Dogs are often kept as pets and companions, and they have been bred in a wide variety of forms and sizes for different purposes, such as hunting, herding, guarding, assisting police and military forces, and providing companionship and emotional support.

If you meant to ask about a specific medical condition or term related to dogs, please provide more context so I can give you an accurate answer.

Actin is a type of protein that forms part of the contractile apparatus in muscle cells, and is also found in various other cell types. It is a globular protein that polymerizes to form long filaments, which are important for many cellular processes such as cell division, cell motility, and the maintenance of cell shape. In muscle cells, actin filaments interact with another type of protein called myosin to enable muscle contraction. Actins can be further divided into different subtypes, including alpha-actin, beta-actin, and gamma-actin, which have distinct functions and expression patterns in the body.

Phosphoproteins are proteins that have been post-translationally modified by the addition of a phosphate group (-PO3H2) onto specific amino acid residues, most commonly serine, threonine, or tyrosine. This process is known as phosphorylation and is mediated by enzymes called kinases. Phosphoproteins play crucial roles in various cellular processes such as signal transduction, cell cycle regulation, metabolism, and gene expression. The addition or removal of a phosphate group can activate or inhibit the function of a protein, thereby serving as a switch to control its activity. Phosphoproteins can be detected and quantified using techniques such as Western blotting, mass spectrometry, and immunofluorescence.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

Capillaries are the smallest blood vessels in the body, with diameters that range from 5 to 10 micrometers. They form a network of tiny tubes that connect the arterioles (small branches of arteries) and venules (small branches of veins), allowing for the exchange of oxygen, carbon dioxide, nutrients, and waste products between the blood and the surrounding tissues.

Capillaries are composed of a single layer of endothelial cells that surround a hollow lumen through which blood flows. The walls of capillaries are extremely thin, allowing for easy diffusion of molecules between the blood and the surrounding tissue. This is essential for maintaining the health and function of all body tissues.

Capillaries can be classified into three types based on their structure and function: continuous, fenestrated, and sinusoidal. Continuous capillaries have a continuous layer of endothelial cells with tight junctions that restrict the passage of large molecules. Fenestrated capillaries have small pores or "fenestrae" in the endothelial cell walls that allow for the passage of larger molecules, such as proteins and lipids. Sinusoidal capillaries are found in organs with high metabolic activity, such as the liver and spleen, and have large, irregular spaces between the endothelial cells that allow for the exchange of even larger molecules.

Overall, capillaries play a critical role in maintaining the health and function of all body tissues by allowing for the exchange of nutrients, oxygen, and waste products between the blood and surrounding tissues.

Alpha-catenin is a protein that plays a crucial role in cell adhesion and the maintenance of the cytoskeleton. It is a component of the cadherin-catenin complex, which is responsible for forming tight junctions between cells, known as adherens junctions. Alpha-catenin binds to beta-catenin, which in turn interacts with cadherins, transmembrane proteins that mediate cell-cell adhesion. This interaction helps to link the actin cytoskeleton to the cadherin-catenin complex, providing strength and stability to adherens junctions. Additionally, alpha-catenin has been implicated in various signaling pathways related to cell growth, differentiation, and migration.

Beta-catenin is a protein that plays a crucial role in gene transcription and cell-cell adhesion. It is a key component of the Wnt signaling pathway, which regulates various processes such as cell proliferation, differentiation, and migration during embryonic development and tissue homeostasis in adults.

In the absence of Wnt signals, beta-catenin forms a complex with other proteins, including adenomatous polyposis coli (APC) and axin, which targets it for degradation by the proteasome. When Wnt ligands bind to their receptors, this complex is disrupted, allowing beta-catenin to accumulate in the cytoplasm and translocate to the nucleus. In the nucleus, beta-catenin interacts with T cell factor/lymphoid enhancer-binding factor (TCF/LEF) transcription factors to activate the transcription of target genes involved in cell fate determination, survival, and proliferation.

Mutations in the genes encoding components of the Wnt signaling pathway, including beta-catenin, have been implicated in various human diseases, such as cancer, developmental disorders, and degenerative conditions.

The cytoskeleton is a complex network of various protein filaments that provides structural support, shape, and stability to the cell. It plays a crucial role in maintaining cellular integrity, intracellular organization, and enabling cell movement. The cytoskeleton is composed of three major types of protein fibers: microfilaments (actin filaments), intermediate filaments, and microtubules. These filaments work together to provide mechanical support, participate in cell division, intracellular transport, and help maintain the cell's architecture. The dynamic nature of the cytoskeleton allows cells to adapt to changing environmental conditions and respond to various stimuli.

Caco-2 cells are a type of human epithelial colorectal adenocarcinoma cell line that is commonly used in scientific research, particularly in the field of drug development and toxicology. These cells are capable of forming a monolayer with tight junctions, which makes them an excellent model for studying intestinal absorption, transport, and metabolism of drugs and other xenobiotic compounds.

Caco-2 cells express many of the transporters and enzymes that are found in the human small intestine, making them a valuable tool for predicting drug absorption and bioavailability in humans. They are also used to study the mechanisms of drug transport across the intestinal epithelium, including passive diffusion and active transport by various transporters.

In addition to their use in drug development, Caco-2 cells are also used to study the toxicological effects of various compounds on human intestinal cells. They can be used to investigate the mechanisms of toxicity, as well as to evaluate the potential for drugs and other compounds to induce intestinal damage or inflammation.

Overall, Caco-2 cells are a widely used and valuable tool in both drug development and toxicology research, providing important insights into the absorption, transport, metabolism, and toxicity of various compounds in the human body.

In the context of medicine and physiology, permeability refers to the ability of a tissue or membrane to allow the passage of fluids, solutes, or gases. It is often used to describe the property of the capillary walls, which control the exchange of substances between the blood and the surrounding tissues.

The permeability of a membrane can be influenced by various factors, including its molecular structure, charge, and the size of the molecules attempting to pass through it. A more permeable membrane allows for easier passage of substances, while a less permeable membrane restricts the movement of substances.

In some cases, changes in permeability can have significant consequences for health. For example, increased permeability of the blood-brain barrier (a specialized type of capillary that regulates the passage of substances into the brain) has been implicated in a number of neurological conditions, including multiple sclerosis, Alzheimer's disease, and traumatic brain injury.

Cell polarity refers to the asymmetric distribution of membrane components, cytoskeleton, and organelles in a cell. This asymmetry is crucial for various cellular functions such as directed transport, cell division, and signal transduction. The plasma membrane of polarized cells exhibits distinct domains with unique protein and lipid compositions that define apical, basal, and lateral surfaces of the cell.

In epithelial cells, for example, the apical surface faces the lumen or external environment, while the basolateral surface interacts with other cells or the extracellular matrix. The establishment and maintenance of cell polarity are regulated by various factors including protein complexes, lipids, and small GTPases. Loss of cell polarity has been implicated in several diseases, including cancer and neurological disorders.

The Fluorescent Antibody Technique (FAT) is a type of immunofluorescence assay used in laboratory medicine and pathology for the detection and localization of specific antigens or antibodies in tissues, cells, or microorganisms. In this technique, a fluorescein-labeled antibody is used to selectively bind to the target antigen or antibody, forming an immune complex. When excited by light of a specific wavelength, the fluorescein label emits light at a longer wavelength, typically visualized as green fluorescence under a fluorescence microscope.

The FAT is widely used in diagnostic microbiology for the identification and characterization of various bacteria, viruses, fungi, and parasites. It has also been applied in the diagnosis of autoimmune diseases and certain cancers by detecting specific antibodies or antigens in patient samples. The main advantage of FAT is its high sensitivity and specificity, allowing for accurate detection and differentiation of various pathogens and disease markers. However, it requires specialized equipment and trained personnel to perform and interpret the results.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

Capillary permeability refers to the ability of substances to pass through the walls of capillaries, which are the smallest blood vessels in the body. These tiny vessels connect the arterioles and venules, allowing for the exchange of nutrients, waste products, and gases between the blood and the surrounding tissues.

The capillary wall is composed of a single layer of endothelial cells that are held together by tight junctions. The permeability of these walls varies depending on the size and charge of the molecules attempting to pass through. Small, uncharged molecules such as water, oxygen, and carbon dioxide can easily diffuse through the capillary wall, while larger or charged molecules such as proteins and large ions have more difficulty passing through.

Increased capillary permeability can occur in response to inflammation, infection, or injury, allowing larger molecules and immune cells to enter the surrounding tissues. This can lead to swelling (edema) and tissue damage if not controlled. Decreased capillary permeability, on the other hand, can lead to impaired nutrient exchange and tissue hypoxia.

Overall, the permeability of capillaries is a critical factor in maintaining the health and function of tissues throughout the body.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Confocal microscopy is a powerful imaging technique used in medical and biological research to obtain high-resolution, contrast-rich images of thick samples. This super-resolution technology provides detailed visualization of cellular structures and processes at various depths within a specimen.

In confocal microscopy, a laser beam focused through a pinhole illuminates a small spot within the sample. The emitted fluorescence or reflected light from this spot is then collected by a detector, passing through a second pinhole that ensures only light from the focal plane reaches the detector. This process eliminates out-of-focus light, resulting in sharp images with improved contrast compared to conventional widefield microscopy.

By scanning the laser beam across the sample in a raster pattern and collecting fluorescence at each point, confocal microscopy generates optical sections of the specimen. These sections can be combined to create three-dimensional reconstructions, allowing researchers to study cellular architecture and interactions within complex tissues.

Confocal microscopy has numerous applications in medical research, including studying protein localization, tracking intracellular dynamics, analyzing cell morphology, and investigating disease mechanisms at the cellular level. Additionally, it is widely used in clinical settings for diagnostic purposes, such as analyzing skin lesions or detecting pathogens in patient samples.

Fluorescence microscopy is a type of microscopy that uses fluorescent dyes or proteins to highlight and visualize specific components within a sample. In this technique, the sample is illuminated with high-energy light, typically ultraviolet (UV) or blue light, which excites the fluorescent molecules causing them to emit lower-energy, longer-wavelength light, usually visible light in the form of various colors. This emitted light is then collected by the microscope and detected to produce an image.

Fluorescence microscopy has several advantages over traditional brightfield microscopy, including the ability to visualize specific structures or molecules within a complex sample, increased sensitivity, and the potential for quantitative analysis. It is widely used in various fields of biology and medicine, such as cell biology, neuroscience, and pathology, to study the structure, function, and interactions of cells and proteins.

There are several types of fluorescence microscopy techniques, including widefield fluorescence microscopy, confocal microscopy, two-photon microscopy, and total internal reflection fluorescence (TIRF) microscopy, each with its own strengths and limitations. These techniques can provide valuable insights into the behavior of cells and proteins in health and disease.

The crystalline lens is a biconvex transparent structure in the eye that helps to refract (bend) light rays and focus them onto the retina. It is located behind the iris and pupil and is suspended by small fibers called zonules that connect it to the ciliary body. The lens can change its shape to accommodate and focus on objects at different distances, a process known as accommodation. With age, the lens may become cloudy or opaque, leading to cataracts.

The endothelium is a thin layer of simple squamous epithelial cells that lines the interior surface of blood vessels, lymphatic vessels, and heart chambers. The vascular endothelium, specifically, refers to the endothelial cells that line the blood vessels. These cells play a crucial role in maintaining vascular homeostasis by regulating vasomotor tone, coagulation, platelet activation, inflammation, and permeability of the vessel wall. They also contribute to the growth and repair of the vascular system and are involved in various pathological processes such as atherosclerosis, hypertension, and diabetes.

Phase-contrast microscopy is a type of optical microscopy that allows visualization of transparent or translucent specimens, such as living cells and their organelles, by increasing the contrast between areas with different refractive indices within the sample. This technique works by converting phase shifts in light passing through the sample into changes in amplitude, which can then be observed as differences in brightness and contrast.

In a phase-contrast microscope, a special condenser and objective are used to create an optical path difference between the direct and diffracted light rays coming from the specimen. The condenser introduces a phase shift for the diffracted light, while the objective contains a phase ring that compensates for this shift in the direct light. This results in the direct light appearing brighter than the diffracted light, creating contrast between areas with different refractive indices within the sample.

Phase-contrast microscopy is particularly useful for observing unstained living cells and their dynamic processes, such as cell division, motility, and secretion, without the need for stains or dyes that might affect their viability or behavior.

Lanthanum is not a medical term itself, but it is a chemical element with the symbol "La" and atomic number 57. It is a soft, ductile, silvery-white metal that belongs to the lanthanide series in the periodic table.

However, in medical contexts, lanthanum may be mentioned as a component of certain medications or medical devices. For example, lanthanum carbonate (trade name Fosrenol) is a medication used to treat hyperphosphatemia (elevated levels of phosphate in the blood) in patients with chronic kidney disease. Lanthanum carbonate works by binding to phosphate in the gastrointestinal tract, preventing its absorption into the bloodstream.

It is important to note that lanthanum compounds are not biologically active and do not have any specific medical effects on their own. Any medical uses of lanthanum are related to its physical or chemical properties, rather than its biological activity.

The intestinal mucosa is the innermost layer of the intestines, which comes into direct contact with digested food and microbes. It is a specialized epithelial tissue that plays crucial roles in nutrient absorption, barrier function, and immune defense. The intestinal mucosa is composed of several cell types, including absorptive enterocytes, mucus-secreting goblet cells, hormone-producing enteroendocrine cells, and immune cells such as lymphocytes and macrophages.

The surface of the intestinal mucosa is covered by a single layer of epithelial cells, which are joined together by tight junctions to form a protective barrier against harmful substances and microorganisms. This barrier also allows for the selective absorption of nutrients into the bloodstream. The intestinal mucosa also contains numerous lymphoid follicles, known as Peyer's patches, which are involved in immune surveillance and defense against pathogens.

In addition to its role in absorption and immunity, the intestinal mucosa is also capable of producing hormones that regulate digestion and metabolism. Dysfunction of the intestinal mucosa can lead to various gastrointestinal disorders, such as inflammatory bowel disease, celiac disease, and food allergies.

Podocytes are specialized cells that make up the visceral epithelial layer of the glomerular basement membrane in the kidney. They have long, interdigitating foot processes that wrap around the capillaries of the glomerulus and play a crucial role in maintaining the filtration barrier of the kidney. The slit diaphragms between the foot processes allow for the passage of small molecules while retaining larger proteins in the bloodstream. Podocytes also contribute to the maintenance and regulation of the glomerular filtration rate, making them essential for normal renal function. Damage or loss of podocytes can lead to proteinuria and kidney disease.

The basement membrane is a thin, specialized layer of extracellular matrix that provides structural support and separates epithelial cells (which line the outer surfaces of organs and blood vessels) from connective tissue. It is composed of two main layers: the basal lamina, which is produced by the epithelial cells, and the reticular lamina, which is produced by the connective tissue. The basement membrane plays important roles in cell adhesion, migration, differentiation, and survival.

The basal lamina is composed mainly of type IV collagen, laminins, nidogens, and proteoglycans, while the reticular lamina contains type III collagen, fibronectin, and other matrix proteins. The basement membrane also contains a variety of growth factors and cytokines that can influence cell behavior.

Defects in the composition or organization of the basement membrane can lead to various diseases, including kidney disease, eye disease, and skin blistering disorders.

Scanning electron microscopy (SEM) is a type of electron microscopy that uses a focused beam of electrons to scan the surface of a sample and produce a high-resolution image. In SEM, a beam of electrons is scanned across the surface of a specimen, and secondary electrons are emitted from the sample due to interactions between the electrons and the atoms in the sample. These secondary electrons are then detected by a detector and used to create an image of the sample's surface topography. SEM can provide detailed images of the surface of a wide range of materials, including metals, polymers, ceramics, and biological samples. It is commonly used in materials science, biology, and electronics for the examination and analysis of surfaces at the micro- and nanoscale.

Rho GTP-binding proteins are a subfamily of the Ras superfamily of small GTPases, which function as molecular switches in various cellular signaling pathways. These proteins play crucial roles in regulating diverse cellular processes such as actin cytoskeleton dynamics, gene expression, cell cycle progression, and cell migration.

Rho GTP-binding proteins cycle between an active GTP-bound state and an inactive GDP-bound state. In the active state, they interact with various downstream effectors to regulate their respective cellular functions. Guanine nucleotide exchange factors (GEFs) activate Rho GTP-binding proteins by promoting the exchange of GDP for GTP, while GTPase-activating proteins (GAPs) inactivate them by enhancing their intrinsic GTP hydrolysis activity.

There are several members of the Rho GTP-binding protein family, including RhoA, RhoB, RhoC, Rac1, Rac2, Rac3, Cdc42, and Rnd proteins, each with distinct functions and downstream effectors. Dysregulation of Rho GTP-binding proteins has been implicated in various human diseases, including cancer, cardiovascular disease, neurological disorders, and inflammatory diseases.

Endothelial cells are the type of cells that line the inner surface of blood vessels, lymphatic vessels, and heart chambers. They play a crucial role in maintaining vascular homeostasis by controlling vasomotor tone, coagulation, platelet activation, and inflammation. Endothelial cells also regulate the transport of molecules between the blood and surrounding tissues, and contribute to the maintenance of the structural integrity of the vasculature. They are flat, elongated cells with a unique morphology that allows them to form a continuous, nonthrombogenic lining inside the vessels. Endothelial cells can be isolated from various tissues and cultured in vitro for research purposes.

The esophagogastric junction (EGJ) is the region of the gastrointestinal tract where the esophagus (the tube that carries food from the mouth to the stomach) meets the stomach. It serves as a physiological sphincter, which helps control the direction of flow and prevent reflux of gastric contents back into the esophagus. The EGJ is also known as the gastroesophageal junction or cardia.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Immunoelectron microscopy (IEM) is a specialized type of electron microscopy that combines the principles of immunochemistry and electron microscopy to detect and localize specific antigens within cells or tissues at the ultrastructural level. This technique allows for the visualization and identification of specific proteins, viruses, or other antigenic structures with a high degree of resolution and specificity.

In IEM, samples are first fixed, embedded, and sectioned to prepare them for electron microscopy. The sections are then treated with specific antibodies that have been labeled with electron-dense markers, such as gold particles or ferritin. These labeled antibodies bind to the target antigens in the sample, allowing for their visualization under an electron microscope.

There are several different methods of IEM, including pre-embedding and post-embedding techniques. Pre-embedding involves labeling the antigens before embedding the sample in resin, while post-embedding involves labeling the antigens after embedding. Post-embedding techniques are generally more commonly used because they allow for better preservation of ultrastructure and higher resolution.

IEM is a valuable tool in many areas of research, including virology, bacteriology, immunology, and cell biology. It can be used to study the structure and function of viruses, bacteria, and other microorganisms, as well as the distribution and localization of specific proteins and antigens within cells and tissues.

Immunohistochemistry (IHC) is a technique used in pathology and laboratory medicine to identify specific proteins or antigens in tissue sections. It combines the principles of immunology and histology to detect the presence and location of these target molecules within cells and tissues. This technique utilizes antibodies that are specific to the protein or antigen of interest, which are then tagged with a detection system such as a chromogen or fluorophore. The stained tissue sections can be examined under a microscope, allowing for the visualization and analysis of the distribution and expression patterns of the target molecule in the context of the tissue architecture. Immunohistochemistry is widely used in diagnostic pathology to help identify various diseases, including cancer, infectious diseases, and immune-mediated disorders.

Keratinocytes are the predominant type of cells found in the epidermis, which is the outermost layer of the skin. These cells are responsible for producing keratin, a tough protein that provides structural support and protection to the skin. Keratinocytes undergo constant turnover, with new cells produced in the basal layer of the epidermis and older cells moving upward and eventually becoming flattened and filled with keratin as they reach the surface of the skin, where they are then shed. They also play a role in the immune response and can release cytokines and other signaling molecules to help protect the body from infection and injury.

The actin cytoskeleton is a complex, dynamic network of filamentous (threadlike) proteins that provides structural support and shape to cells, allows for cell movement and division, and plays a role in intracellular transport. Actin filaments are composed of actin monomers that polymerize to form long, thin fibers. These filaments can be organized into different structures, such as stress fibers, which provide tension and support, or lamellipodia and filopodia, which are involved in cell motility. The actin cytoskeleton is constantly remodeling in response to various intracellular and extracellular signals, allowing for changes in cell shape and behavior.

Cell movement, also known as cell motility, refers to the ability of cells to move independently and change their location within tissue or inside the body. This process is essential for various biological functions, including embryonic development, wound healing, immune responses, and cancer metastasis.

There are several types of cell movement, including:

1. **Crawling or mesenchymal migration:** Cells move by extending and retracting protrusions called pseudopodia or filopodia, which contain actin filaments. This type of movement is common in fibroblasts, immune cells, and cancer cells during tissue invasion and metastasis.
2. **Amoeboid migration:** Cells move by changing their shape and squeezing through tight spaces without forming protrusions. This type of movement is often observed in white blood cells (leukocytes) as they migrate through the body to fight infections.
3. **Pseudopodial extension:** Cells extend pseudopodia, which are temporary cytoplasmic projections containing actin filaments. These protrusions help the cell explore its environment and move forward.
4. **Bacterial flagellar motion:** Bacteria use a whip-like structure called a flagellum to propel themselves through their environment. The rotation of the flagellum is driven by a molecular motor in the bacterial cell membrane.
5. **Ciliary and ependymal movement:** Ciliated cells, such as those lining the respiratory tract and fallopian tubes, have hair-like structures called cilia that beat in coordinated waves to move fluids or mucus across the cell surface.

Cell movement is regulated by a complex interplay of signaling pathways, cytoskeletal rearrangements, and adhesion molecules, which enable cells to respond to environmental cues and navigate through tissues.

Tight junction proteins are specialized proteins that play a crucial role in the formation and maintenance of tight junctions, which are intercellular structures that form a barrier to prevent the passage of molecules between cells. These proteins are found in the apical region of epithelial and endothelial cells and help to create a tight seal between adjacent cells.

Tight junction proteins can be classified into two major groups: transmembrane proteins and cytoplasmic plaque proteins. Transmembrane proteins, such as occludin and claudins, span the cell membrane and interact with each other to form the backbone of the tight junction. Cytoplasmic plaque proteins, such as zonula occludens (ZO) proteins, anchor the transmembrane proteins to the cytoskeleton and help to regulate their function.

Tight junction proteins are essential for maintaining the integrity of epithelial and endothelial barriers in various organs, including the gut, lungs, and blood-brain barrier. Dysfunction of these proteins has been implicated in a variety of diseases, such as inflammatory bowel disease, cancer, and neurological disorders.

CD (cluster of differentiation) antigens are cell-surface proteins that are expressed on leukocytes (white blood cells) and can be used to identify and distinguish different subsets of these cells. They are important markers in the field of immunology and hematology, and are commonly used to diagnose and monitor various diseases, including cancer, autoimmune disorders, and infectious diseases.

CD antigens are designated by numbers, such as CD4, CD8, CD19, etc., which refer to specific proteins found on the surface of different types of leukocytes. For example, CD4 is a protein found on the surface of helper T cells, while CD8 is found on cytotoxic T cells.

CD antigens can be used as targets for immunotherapy, such as monoclonal antibody therapy, in which antibodies are designed to bind to specific CD antigens and trigger an immune response against cancer cells or infected cells. They can also be used as markers to monitor the effectiveness of treatments and to detect minimal residual disease (MRD) after treatment.

It's important to note that not all CD antigens are exclusive to leukocytes, some can be found on other cell types as well, and their expression can vary depending on the activation state or differentiation stage of the cells.

Rac (Ras-related C3 botulinum toxin substrate) GTP-binding proteins are a subfamily of the Rho family of small GTPases, which function as molecular switches that regulate various cellular processes, including actin cytoskeleton organization, cell adhesion, and gene transcription.

Rac GTP-binding proteins cycle between an inactive GDP-bound state and an active GTP-bound state. When Rac is in its active state, it interacts with downstream effectors to regulate various signaling pathways that control cell behavior. Activation of Rac promotes the formation of lamellipodia and membrane ruffles, which are important for cell migration and invasion.

Rac GTP-binding proteins have been implicated in a variety of physiological and pathological processes, including embryonic development, immune function, and cancer. Dysregulation of Rac signaling has been associated with various diseases, such as inflammatory disorders, neurological disorders, and cancer. Therefore, understanding the regulation and function of Rac GTP-binding proteins is crucial for developing therapeutic strategies to target these diseases.

Holliday junction resolvases are a type of enzyme that are involved in the process of genetic recombination. They are named after Robin Holliday, who first proposed the existence of a structure called a Holliday junction during genetic recombination.

A Holliday junction is a four-way DNA structure that forms when two DNA molecules exchange genetic material during recombination. The junction is held together by hydrogen bonds between complementary base pairs, and it can move along the DNA molecules through a process called branch migration.

Holliday junction resolvases are responsible for cleaving the DNA strands at the Holliday junction, resolving the structure into two separate DNA molecules. They do this by introducing nicks in the phosphodiester backbone of the DNA strands on either side of the junction and then joining the broken ends together. This results in the exchange of genetic material between the two original DNA molecules.

There are several different types of Holliday junction resolvases, including the bacterial RuvC and RecU enzymes, as well as the eukaryotic Flap endonuclease 1 (FEN1) and XPF/ERCC1 complexes. These enzymes have different specificities for cleaving the DNA strands at the Holliday junction, but they all play important roles in ensuring that genetic recombination occurs accurately and efficiently.

CD31 (also known as PECAM-1 or Platelet Endothelial Cell Adhesion Molecule-1) is a type of protein that is found on the surface of certain cells in the body, including platelets, endothelial cells (which line the blood vessels), and some immune cells.

CD31 functions as a cell adhesion molecule, meaning it helps cells stick together and interact with each other. It plays important roles in various physiological processes, such as the regulation of leukocyte migration, angiogenesis (the formation of new blood vessels), hemostasis (the process that stops bleeding), and thrombosis (the formation of a blood clot inside a blood vessel).

As an antigen, CD31 is used in immunological techniques to identify and characterize cells expressing this protein. Antigens are substances that can be recognized by the immune system and stimulate an immune response. In the case of CD31, antibodies specific to this protein can be used to detect its presence on the surface of cells, providing valuable information for research and diagnostic purposes.

The Blood-Brain Barrier (BBB) is a highly specialized, selective interface between the central nervous system (CNS) and the circulating blood. It is formed by unique endothelial cells that line the brain's capillaries, along with tight junctions, astrocytic foot processes, and pericytes, which together restrict the passage of substances from the bloodstream into the CNS. This barrier serves to protect the brain from harmful agents and maintain a stable environment for proper neural function. However, it also poses a challenge in delivering therapeutics to the CNS, as most large and hydrophilic molecules cannot cross the BBB.

Signal transduction is the process by which a cell converts an extracellular signal, such as a hormone or neurotransmitter, into an intracellular response. This involves a series of molecular events that transmit the signal from the cell surface to the interior of the cell, ultimately resulting in changes in gene expression, protein activity, or metabolism.

The process typically begins with the binding of the extracellular signal to a receptor located on the cell membrane. This binding event activates the receptor, which then triggers a cascade of intracellular signaling molecules, such as second messengers, protein kinases, and ion channels. These molecules amplify and propagate the signal, ultimately leading to the activation or inhibition of specific cellular responses.

Signal transduction pathways are highly regulated and can be modulated by various factors, including other signaling molecules, post-translational modifications, and feedback mechanisms. Dysregulation of these pathways has been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

Transfection is a term used in molecular biology that refers to the process of deliberately introducing foreign genetic material (DNA, RNA or artificial gene constructs) into cells. This is typically done using chemical or physical methods, such as lipofection or electroporation. Transfection is widely used in research and medical settings for various purposes, including studying gene function, producing proteins, developing gene therapies, and creating genetically modified organisms. It's important to note that transfection is different from transduction, which is the process of introducing genetic material into cells using viruses as vectors.

Transmission electron microscopy (TEM) is a type of microscopy in which an electron beam is transmitted through a ultra-thin specimen, interacting with it as it passes through. An image is formed from the interaction of the electrons with the specimen; the image is then magnified and visualized on a fluorescent screen or recorded on an electronic detector (or photographic film in older models).

TEM can provide high-resolution, high-magnification images that can reveal the internal structure of specimens including cells, viruses, and even molecules. It is widely used in biological and materials science research to investigate the ultrastructure of cells, tissues and materials. In medicine, TEM is used for diagnostic purposes in fields such as virology and bacteriology.

It's important to note that preparing a sample for TEM is a complex process, requiring specialized techniques to create thin (50-100 nm) specimens. These include cutting ultrathin sections of embedded samples using an ultramicrotome, staining with heavy metal salts, and positive staining or negative staining methods.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Electric conductivity, also known as electrical conductance, is a measure of a material's ability to allow the flow of electric current through it. It is usually measured in units of Siemens per meter (S/m) or ohm-meters (Ω-m).

In medical terms, electric conductivity can refer to the body's ability to conduct electrical signals, which is important for various physiological processes such as nerve impulse transmission and muscle contraction. Abnormalities in electrical conductivity can be associated with various medical conditions, including neurological disorders and heart diseases.

For example, in electrocardiography (ECG), the electric conductivity of the heart is measured to assess its electrical activity and identify any abnormalities that may indicate heart disease. Similarly, in electromyography (EMG), the electric conductivity of muscles is measured to diagnose neuromuscular disorders.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Phosphorylation is the process of adding a phosphate group (a molecule consisting of one phosphorus atom and four oxygen atoms) to a protein or other organic molecule, which is usually done by enzymes called kinases. This post-translational modification can change the function, localization, or activity of the target molecule, playing a crucial role in various cellular processes such as signal transduction, metabolism, and regulation of gene expression. Phosphorylation is reversible, and the removal of the phosphate group is facilitated by enzymes called phosphatases.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

A kidney, in medical terms, is one of two bean-shaped organs located in the lower back region of the body. They are essential for maintaining homeostasis within the body by performing several crucial functions such as:

1. Regulation of water and electrolyte balance: Kidneys help regulate the amount of water and various electrolytes like sodium, potassium, and calcium in the bloodstream to maintain a stable internal environment.

2. Excretion of waste products: They filter waste products from the blood, including urea (a byproduct of protein metabolism), creatinine (a breakdown product of muscle tissue), and other harmful substances that result from normal cellular functions or external sources like medications and toxins.

3. Endocrine function: Kidneys produce several hormones with important roles in the body, such as erythropoietin (stimulates red blood cell production), renin (regulates blood pressure), and calcitriol (activated form of vitamin D that helps regulate calcium homeostasis).

4. pH balance regulation: Kidneys maintain the proper acid-base balance in the body by excreting either hydrogen ions or bicarbonate ions, depending on whether the blood is too acidic or too alkaline.

5. Blood pressure control: The kidneys play a significant role in regulating blood pressure through the renin-angiotensin-aldosterone system (RAAS), which constricts blood vessels and promotes sodium and water retention to increase blood volume and, consequently, blood pressure.

Anatomically, each kidney is approximately 10-12 cm long, 5-7 cm wide, and 3 cm thick, with a weight of about 120-170 grams. They are surrounded by a protective layer of fat and connected to the urinary system through the renal pelvis, ureters, bladder, and urethra.

Morphogenesis is a term used in developmental biology and refers to the process by which cells give rise to tissues and organs with specific shapes, structures, and patterns during embryonic development. This process involves complex interactions between genes, cells, and the extracellular environment that result in the coordinated movement and differentiation of cells into specialized functional units.

Morphogenesis is a dynamic and highly regulated process that involves several mechanisms, including cell proliferation, death, migration, adhesion, and differentiation. These processes are controlled by genetic programs and signaling pathways that respond to environmental cues and regulate the behavior of individual cells within a developing tissue or organ.

The study of morphogenesis is important for understanding how complex biological structures form during development and how these processes can go awry in disease states such as cancer, birth defects, and degenerative disorders.

Cytoplasm is the material within a eukaryotic cell (a cell with a true nucleus) that lies between the nuclear membrane and the cell membrane. It is composed of an aqueous solution called cytosol, in which various organelles such as mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles are suspended. Cytoplasm also contains a variety of dissolved nutrients, metabolites, ions, and enzymes that are involved in various cellular processes such as metabolism, signaling, and transport. It is where most of the cell's metabolic activities take place, and it plays a crucial role in maintaining the structure and function of the cell.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

Protein transport, in the context of cellular biology, refers to the process by which proteins are actively moved from one location to another within or between cells. This is a crucial mechanism for maintaining proper cell function and regulation.

Intracellular protein transport involves the movement of proteins within a single cell. Proteins can be transported across membranes (such as the nuclear envelope, endoplasmic reticulum, Golgi apparatus, or plasma membrane) via specialized transport systems like vesicles and transport channels.

Intercellular protein transport refers to the movement of proteins from one cell to another, often facilitated by exocytosis (release of proteins in vesicles) and endocytosis (uptake of extracellular substances via membrane-bound vesicles). This is essential for communication between cells, immune response, and other physiological processes.

It's important to note that any disruption in protein transport can lead to various diseases, including neurological disorders, cancer, and metabolic conditions.

Cell differentiation is the process by which a less specialized cell, or stem cell, becomes a more specialized cell type with specific functions and structures. This process involves changes in gene expression, which are regulated by various intracellular signaling pathways and transcription factors. Differentiation results in the development of distinct cell types that make up tissues and organs in multicellular organisms. It is a crucial aspect of embryonic development, tissue repair, and maintenance of homeostasis in the body.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Immunoblotting, also known as western blotting, is a laboratory technique used in molecular biology and immunogenetics to detect and quantify specific proteins in a complex mixture. This technique combines the electrophoretic separation of proteins by gel electrophoresis with their detection using antibodies that recognize specific epitopes (protein fragments) on the target protein.

The process involves several steps: first, the protein sample is separated based on size through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Next, the separated proteins are transferred onto a nitrocellulose or polyvinylidene fluoride (PVDF) membrane using an electric field. The membrane is then blocked with a blocking agent to prevent non-specific binding of antibodies.

After blocking, the membrane is incubated with a primary antibody that specifically recognizes the target protein. Following this, the membrane is washed to remove unbound primary antibodies and then incubated with a secondary antibody conjugated to an enzyme such as horseradish peroxidase (HRP) or alkaline phosphatase (AP). The enzyme catalyzes a colorimetric or chemiluminescent reaction that allows for the detection of the target protein.

Immunoblotting is widely used in research and clinical settings to study protein expression, post-translational modifications, protein-protein interactions, and disease biomarkers. It provides high specificity and sensitivity, making it a valuable tool for identifying and quantifying proteins in various biological samples.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Trans-activators are proteins that increase the transcriptional activity of a gene or a set of genes. They do this by binding to specific DNA sequences and interacting with the transcription machinery, thereby enhancing the recruitment and assembly of the complexes needed for transcription. In some cases, trans-activators can also modulate the chromatin structure to make the template more accessible to the transcription machinery.

In the context of HIV (Human Immunodeficiency Virus) infection, the term "trans-activator" is often used specifically to refer to the Tat protein. The Tat protein is a viral regulatory protein that plays a critical role in the replication of HIV by activating the transcription of the viral genome. It does this by binding to a specific RNA structure called the Trans-Activation Response Element (TAR) located at the 5' end of all nascent HIV transcripts, and recruiting cellular cofactors that enhance the processivity and efficiency of RNA polymerase II, leading to increased viral gene expression.

Western blotting is a laboratory technique used in molecular biology to detect and quantify specific proteins in a mixture of many different proteins. This technique is commonly used to confirm the expression of a protein of interest, determine its size, and investigate its post-translational modifications. The name "Western" blotting distinguishes this technique from Southern blotting (for DNA) and Northern blotting (for RNA).

The Western blotting procedure involves several steps:

1. Protein extraction: The sample containing the proteins of interest is first extracted, often by breaking open cells or tissues and using a buffer to extract the proteins.
2. Separation of proteins by electrophoresis: The extracted proteins are then separated based on their size by loading them onto a polyacrylamide gel and running an electric current through the gel (a process called sodium dodecyl sulfate-polyacrylamide gel electrophoresis or SDS-PAGE). This separates the proteins according to their molecular weight, with smaller proteins migrating faster than larger ones.
3. Transfer of proteins to a membrane: After separation, the proteins are transferred from the gel onto a nitrocellulose or polyvinylidene fluoride (PVDF) membrane using an electric current in a process called blotting. This creates a replica of the protein pattern on the gel but now immobilized on the membrane for further analysis.
4. Blocking: The membrane is then blocked with a blocking agent, such as non-fat dry milk or bovine serum albumin (BSA), to prevent non-specific binding of antibodies in subsequent steps.
5. Primary antibody incubation: A primary antibody that specifically recognizes the protein of interest is added and allowed to bind to its target protein on the membrane. This step may be performed at room temperature or 4°C overnight, depending on the antibody's properties.
6. Washing: The membrane is washed with a buffer to remove unbound primary antibodies.
7. Secondary antibody incubation: A secondary antibody that recognizes the primary antibody (often coupled to an enzyme or fluorophore) is added and allowed to bind to the primary antibody. This step may involve using a horseradish peroxidase (HRP)-conjugated or alkaline phosphatase (AP)-conjugated secondary antibody, depending on the detection method used later.
8. Washing: The membrane is washed again to remove unbound secondary antibodies.
9. Detection: A detection reagent is added to visualize the protein of interest by detecting the signal generated from the enzyme-conjugated or fluorophore-conjugated secondary antibody. This can be done using chemiluminescent, colorimetric, or fluorescent methods.
10. Analysis: The resulting image is analyzed to determine the presence and quantity of the protein of interest in the sample.

Western blotting is a powerful technique for identifying and quantifying specific proteins within complex mixtures. It can be used to study protein expression, post-translational modifications, protein-protein interactions, and more. However, it requires careful optimization and validation to ensure accurate and reproducible results.

The umbilical veins are blood vessels in the umbilical cord that carry oxygenated and nutrient-rich blood from the mother to the developing fetus during pregnancy. There are typically two umbilical veins, one of which usually degenerates and becomes obliterated, leaving a single functional vein. This remaining vein is known as the larger umbilical vein or the venous duct. It enters the fetal abdomen through the umbilicus and passes through the liver, where it branches off to form the portal sinus. Ultimately, the blood from the umbilical vein mixes with the blood from the inferior vena cava and is pumped to the heart through the right atrium.

It's important to note that after birth, the umbilical veins are no longer needed and undergo involution, becoming the ligamentum teres in the adult.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

Membrane potential is the electrical potential difference across a cell membrane, typically for excitable cells such as nerve and muscle cells. It is the difference in electric charge between the inside and outside of a cell, created by the selective permeability of the cell membrane to different ions. The resting membrane potential of a typical animal cell is around -70 mV, with the interior being negative relative to the exterior. This potential is generated and maintained by the active transport of ions across the membrane, primarily through the action of the sodium-potassium pump. Membrane potentials play a crucial role in many physiological processes, including the transmission of nerve impulses and the contraction of muscle cells.

"Cruciform DNA" is a term used to describe a specific conformation or structure that a double-stranded DNA molecule can adopt. It is so-called because the structure resembles the shape of a cross or crucifix.

This conformation arises when two inverted repeats of DNA sequence are located close to each other on the same DNA molecule, such that they can pair up and form a stable secondary structure. This results in the formation of a hairpin loop at each end of the inverted repeat sequences, with the loops pointing towards each other and the intervening sequences forming two arms that cross in the middle.

Cruciform structures are important in various biological processes, including DNA replication, repair, and recombination. However, they can also pose challenges to these processes, as the crossing of the DNA strands can create topological constraints that must be resolved before replication or transcription can proceed.

It's worth noting that cruciform structures are not stable in solution and are usually only observed under specific conditions, such as when the DNA is supercoiled or when negative supercoiling is introduced through the action of enzymes like topoisomerases.

Recombinant fusion proteins are artificially created biomolecules that combine the functional domains or properties of two or more different proteins into a single protein entity. They are generated through recombinant DNA technology, where the genes encoding the desired protein domains are linked together and expressed as a single, chimeric gene in a host organism, such as bacteria, yeast, or mammalian cells.

The resulting fusion protein retains the functional properties of its individual constituent proteins, allowing for novel applications in research, diagnostics, and therapeutics. For instance, recombinant fusion proteins can be designed to enhance protein stability, solubility, or immunogenicity, making them valuable tools for studying protein-protein interactions, developing targeted therapies, or generating vaccines against infectious diseases or cancer.

Examples of recombinant fusion proteins include:

1. Etaglunatide (ABT-523): A soluble Fc fusion protein that combines the heavy chain fragment crystallizable region (Fc) of an immunoglobulin with the extracellular domain of the human interleukin-6 receptor (IL-6R). This fusion protein functions as a decoy receptor, neutralizing IL-6 and its downstream signaling pathways in rheumatoid arthritis.
2. Etanercept (Enbrel): A soluble TNF receptor p75 Fc fusion protein that binds to tumor necrosis factor-alpha (TNF-α) and inhibits its proinflammatory activity, making it a valuable therapeutic option for treating autoimmune diseases like rheumatoid arthritis, ankylosing spondylitis, and psoriasis.
3. Abatacept (Orencia): A fusion protein consisting of the extracellular domain of cytotoxic T-lymphocyte antigen 4 (CTLA-4) linked to the Fc region of an immunoglobulin, which downregulates T-cell activation and proliferation in autoimmune diseases like rheumatoid arthritis.
4. Belimumab (Benlysta): A monoclonal antibody that targets B-lymphocyte stimulator (BLyS) protein, preventing its interaction with the B-cell surface receptor and inhibiting B-cell activation in systemic lupus erythematosus (SLE).
5. Romiplostim (Nplate): A fusion protein consisting of a thrombopoietin receptor agonist peptide linked to an immunoglobulin Fc region, which stimulates platelet production in patients with chronic immune thrombocytopenia (ITP).
6. Darbepoetin alfa (Aranesp): A hyperglycosylated erythropoiesis-stimulating protein that functions as a longer-acting form of recombinant human erythropoietin, used to treat anemia in patients with chronic kidney disease or cancer.
7. Palivizumab (Synagis): A monoclonal antibody directed against the F protein of respiratory syncytial virus (RSV), which prevents RSV infection and is administered prophylactically to high-risk infants during the RSV season.
8. Ranibizumab (Lucentis): A recombinant humanized monoclonal antibody fragment that binds and inhibits vascular endothelial growth factor A (VEGF-A), used in the treatment of age-related macular degeneration, diabetic retinopathy, and other ocular disorders.
9. Cetuximab (Erbitux): A chimeric monoclonal antibody that binds to epidermal growth factor receptor (EGFR), used in the treatment of colorectal cancer and head and neck squamous cell carcinoma.
10. Adalimumab (Humira): A fully humanized monoclonal antibody that targets tumor necrosis factor-alpha (TNF-α), used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriasis, and Crohn's disease.
11. Bevacizumab (Avastin): A recombinant humanized monoclonal antibody that binds to VEGF-A, used in the treatment of various cancers, including colorectal, lung, breast, and kidney cancer.
12. Trastuzumab (Herceptin): A humanized monoclonal antibody that targets HER2/neu receptor, used in the treatment of breast cancer.
13. Rituximab (Rituxan): A chimeric monoclonal antibody that binds to CD20 antigen on B cells, used in the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis.
14. Palivizumab (Synagis): A humanized monoclonal antibody that binds to the F protein of respiratory syncytial virus, used in the prevention of respiratory syncytial virus infection in high-risk infants.
15. Infliximab (Remicade): A chimeric monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including Crohn's disease, ulcerative colitis, rheumatoid arthritis, and ankylosing spondylitis.
16. Natalizumab (Tysabri): A humanized monoclonal antibody that binds to α4β1 integrin, used in the treatment of multiple sclerosis and Crohn's disease.
17. Adalimumab (Humira): A fully human monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, and ulcerative colitis.
18. Golimumab (Simponi): A fully human monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis.
19. Certolizumab pegol (Cimzia): A PEGylated Fab' fragment of a humanized monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and Crohn's disease.
20. Ustekinumab (Stelara): A fully human monoclonal antibody that targets IL-12 and IL-23, used in the treatment of psoriasis, psoriatic arthritis, and Crohn's disease.
21. Secukinumab (Cosentyx): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis, psoriatic arthritis, and ankylosing spondylitis.
22. Ixekizumab (Taltz): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis and psoriatic arthritis.
23. Brodalumab (Siliq): A fully human monoclonal antibody that targets IL-17 receptor A, used in the treatment of psoriasis.
24. Sarilumab (Kevzara): A fully human monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis.
25. Tocilizumab (Actemra): A humanized monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis, polyarticular juvenile idiopathic arthritis, giant cell arteritis, and chimeric antigen receptor T-cell-induced cytokine release syndrome.
26. Siltuximab (Sylvant): A chimeric monoclonal antibody that targets IL-6, used in the treatment of multicentric Castleman disease.
27. Satralizumab (Enspryng): A humanized monoclonal antibody that targets IL-6 receptor alpha, used in the treatment of neuromyelitis optica spectrum disorder.
28. Sirukumab (Plivensia): A human monoclonal antibody that targets IL-6, used in the treatment

Tyrosine is an non-essential amino acid, which means that it can be synthesized by the human body from another amino acid called phenylalanine. Its name is derived from the Greek word "tyros," which means cheese, as it was first isolated from casein, a protein found in cheese.

Tyrosine plays a crucial role in the production of several important substances in the body, including neurotransmitters such as dopamine, norepinephrine, and epinephrine, which are involved in various physiological processes, including mood regulation, stress response, and cognitive functions. It also serves as a precursor to melanin, the pigment responsible for skin, hair, and eye color.

In addition, tyrosine is involved in the structure of proteins and is essential for normal growth and development. Some individuals may require tyrosine supplementation if they have a genetic disorder that affects tyrosine metabolism or if they are phenylketonurics (PKU), who cannot metabolize phenylalanine, which can lead to elevated tyrosine levels in the blood. However, it is important to consult with a healthcare professional before starting any supplementation regimen.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

A "knockout" mouse is a genetically engineered mouse in which one or more genes have been deleted or "knocked out" using molecular biology techniques. This allows researchers to study the function of specific genes and their role in various biological processes, as well as potential associations with human diseases. The mice are generated by introducing targeted DNA modifications into embryonic stem cells, which are then used to create a live animal. Knockout mice have been widely used in biomedical research to investigate gene function, disease mechanisms, and potential therapeutic targets.

Monoclonal antibodies are a type of antibody that are identical because they are produced by a single clone of cells. They are laboratory-produced molecules that act like human antibodies in the immune system. They can be designed to attach to specific proteins found on the surface of cancer cells, making them useful for targeting and treating cancer. Monoclonal antibodies can also be used as a therapy for other diseases, such as autoimmune disorders and inflammatory conditions.

Monoclonal antibodies are produced by fusing a single type of immune cell, called a B cell, with a tumor cell to create a hybrid cell, or hybridoma. This hybrid cell is then able to replicate indefinitely, producing a large number of identical copies of the original antibody. These antibodies can be further modified and engineered to enhance their ability to bind to specific targets, increase their stability, and improve their effectiveness as therapeutic agents.

Monoclonal antibodies have several mechanisms of action in cancer therapy. They can directly kill cancer cells by binding to them and triggering an immune response. They can also block the signals that promote cancer growth and survival. Additionally, monoclonal antibodies can be used to deliver drugs or radiation directly to cancer cells, increasing the effectiveness of these treatments while minimizing their side effects on healthy tissues.

Monoclonal antibodies have become an important tool in modern medicine, with several approved for use in cancer therapy and other diseases. They are continuing to be studied and developed as a promising approach to treating a wide range of medical conditions.

Fibroblasts are specialized cells that play a critical role in the body's immune response and wound healing process. They are responsible for producing and maintaining the extracellular matrix (ECM), which is the non-cellular component present within all tissues and organs, providing structural support and biochemical signals for surrounding cells.

Fibroblasts produce various ECM proteins such as collagens, elastin, fibronectin, and laminins, forming a complex network of fibers that give tissues their strength and flexibility. They also help in the regulation of tissue homeostasis by controlling the turnover of ECM components through the process of remodeling.

In response to injury or infection, fibroblasts become activated and start to proliferate rapidly, migrating towards the site of damage. Here, they participate in the inflammatory response, releasing cytokines and chemokines that attract immune cells to the area. Additionally, they deposit new ECM components to help repair the damaged tissue and restore its functionality.

Dysregulation of fibroblast activity has been implicated in several pathological conditions, including fibrosis (excessive scarring), cancer (where they can contribute to tumor growth and progression), and autoimmune diseases (such as rheumatoid arthritis).

'Gene expression regulation' refers to the processes that control whether, when, and where a particular gene is expressed, meaning the production of a specific protein or functional RNA encoded by that gene. This complex mechanism can be influenced by various factors such as transcription factors, chromatin remodeling, DNA methylation, non-coding RNAs, and post-transcriptional modifications, among others. Proper regulation of gene expression is crucial for normal cellular function, development, and maintaining homeostasis in living organisms. Dysregulation of gene expression can lead to various diseases, including cancer and genetic disorders.

... is a process by which intercellular junctions mediate signals that allow normal cells to inhibit the ... In: Kandous, M. (Eds.) Intercellular communication and Cancer. pp. 297-342. Heidelberg: Springer-Verlag. (Cell communication, ...
As an MGH pathology resident, he co-authored research papers on intercellular junctions, cancer cell, and red cell membranes. ... Weinstein, Ronald S.; Merk, Frederick B.; Alroy, Joseph (1976). The Structure and Function of Intercellular Junctions in Cancer ... McNutt, N. Scott; Weinstein, Ronald S. (1969-08-08). "Carcinoma of the Cervix: Deficiency of Nexus Intercellular Junctions". ... Scott McNutt, N.; Weinstein, Ronald S. (1973). "Membrane ultrastructure at mammalian intercellular junctions". Progress in ...
Are gap junctions required for intercellular coupling?". Experientia. 46 (10): 1002-5. doi:10.1007/BF01940654. PMID 2226711. ... Gap junctions have been demonstrated in rare circumstances as one coupling mechanism between ICC and smooth muscle cells. ... Electron microscopic and dye coupling studies to date have confirmed gap junctions as the major coupling mechanisms between ... Hanani, Menachem; Farrugia, Gianrico; Komuro, Terumasa (2004). Intercellular Coupling of Interstitial Cells of Cajal in the ...
Takai Y, Nakanishi H (Jan 2003). "Nectin and afadin: novel organizers of intercellular junctions". Journal of Cell Science. 116 ... Tight junction protein 1, and USP9X. GRCh38: Ensembl release 89: ENSG00000130396 - Ensembl, May 2017 GRCm38: Ensembl release 89 ... A novel actin filament-binding protein with one PDZ domain localized at cadherin-based cell-to-cell adherens junction". The ... and vinculin-binding protein localized at cell-cell and cell-matrix adherens junctions". The Journal of Cell Biology. 144 (5): ...
Fan J, Ray P, Lu Y, Kaur G, Schwarz J, Wan L (24 October 2018). "Cell chirality regulates intercellular junctions and ...
Intercellular junctions Gametogenesis Spectrin Cyclin Telfer, W. H. 1975. Development and physiology of the oocyte-nurse cell ... 2011). Germ Cell Intercellular Bridges. Cold Spring Harb Perspect Biol 3:a005850 doi: 10.1101/cshperspect.a005850 de Cuevas, M ... Intercellular bridges also connect developing germ cells in mammals, contributing to cell cycle synchrony and gamete quality ... Future studies are required to elucidate all of the functions that arise from cell-cell communication through intercellular ...
Desmosomes are intercellular junctions that tightly link adjacent cells. Desmoplakin is an obligate component of functional ... a pivotal role for plakoglobin in the recruitment of desmoplakin to intercellular junctions". J. Cell Sci. 111 (20): 3045-57. ... "VE-cadherin and desmoplakin are assembled into dermal microvascular endothelial intercellular junctions: ... desmoplakin from cell-cell interfaces disrupts anchorage of intermediate filament bundles and alters intercellular junction ...
Gruijters, WT; Kistler, J; Bullivant, S (October 1987). "Formation, distribution and dissociation of intercellular junctions in ... Gruijters, WT (July 1989). "A non-connexon protein (MIP) is involved in eye lens gap-junction formation". Journal of Cell ...
The lens fiber cytoplasms are linked together via gap junctions, intercellular bridges and interdigitations of the cells that ... Gruijters, WT; Kistler, J; Bullivant, S (October 1987). "Formation, distribution and dissociation of intercellular junctions in ... Gruijters, WT (July 1989). "A non-connexon protein (MIP) is involved in eye lens gap-junction formation". Journal of Cell ... molecules less than 100 daltons in size among cells via gap junctions, and calcium using transporters/regulators (TRPV channels ...
The molecular structure of gap junctions makes them sensitive and responsive to intercellular currents. This sensitivity allows ... As gap junctions have a major role in regulating the homeostasis of the liver, an abnormal expression of gap junctions can be a ... Gap junctions permit the passive diffusion of materials-such as ions-across the cytoplasm of one cell to another; this junction ... Kjenseth, Ane; Fykerud, Tone; Rivedal, Edgar; Leithe, Edward (2010-03-04). "Regulation of gap junction intercellular ...
... a pivotal role for plakoglobin in the recruitment of desmoplakin to intercellular junctions". Journal of Cell Science. 111 (20 ... a protein common to different kinds of intercellular adhering junctions". Cell. 46 (7): 1063-73. doi:10.1016/0092-8674(86)90706 ... a protein common to different kinds of intercellular adhering junctions". Cell. 46 (7): 1063-73. doi:10.1016/0092-8674(86)90706 ... "VE-cadherin and desmoplakin are assembled into dermal microvascular endothelial intercellular junctions: ...
"Immunolocalization of MP70 in lens fiber 16-17-nm intercellular junctions". The Journal of Cell Biology. 104 (3): 565-572. doi: ...
Intercellular bridges are larger than gap junction ICCs so are able to allow the movement of not only small signaling molecules ... Gap junctions can form intercellular links, effectively a tiny direct regulated "pipe" called a connexon pair between the ... Another form of transfer of pieces of membrane around junctions is called trans-endocytosis. Some large intercellular vesicles ... Gruijters, W (2003). "Are gap junction membrane plaques implicated in intercellular vesicle transfer?". Cell Biology ...
At gap junctions, the intercellular space is between 2 and 4 nm and hemichannels in the membrane of each cell are aligned with ... Gap junction modulation Gap junction protein Innexin Vinnexin Intercalated disc Ion channel Junctional complex Tight junction ... "gap junction" and "gap junction plaque" non-interchangeable as the area of the gap junction plaque may contain proteins other ... "gap junction" and "gap junction plaque" non-interchangeable. To summarize, in early literature the term "gap junction" referred ...
"Tight junctions (zonula occludens) are composed of transmembrane proteins that make contact across the intercellular space and ... Blaskewicz CD, Pudney J, Anderson DJ (July 2011). "Structure and function of intercellular junctions in human cervical and ... The three types of structural adhesions between epithelial cells are: tight junctions, adherens junctions, and desmosomes. " ... Adherens junctions (zonula adherens) connect bundles of actin filaments from cell to cell to form a continuous adhesion belt, ...
ISBN 978-1-4939-3099-9. Blaskewicz CD, Pudney J, Anderson DJ (July 2011). "Structure and function of intercellular junctions in ...
3FTx binding interferes with cholinergic intercellular signaling particularly at neuromuscular junctions and causes paralysis. ... Most members of the family are neurotoxins that act on cholinergic intercellular signaling; the alpha-neurotoxin family ... the subunit composition of tissue-specific nAChRs and the detailed pharmacological understanding of the neuromuscular junction ...
Its normal cellular function is in the establishment of intercellular adherens junctions between epithelial cells. The external ... It is a transmembrane protein that is involved in forming junctions between neighboring cells. It is also the molecule that ...
This gene encodes a protein located on a cytoplasmic membrane surface of intercellular tight junctions. The encoded protein may ... Gap junction protein, alpha 1, KIRREL, MLLT4, Occludin, TJP3, and Tight junction protein 2. Tight junction ENSG00000104067 ... "The tight junction protein ZO-1 is homologous to the Drosophila discs-large tumor suppressor protein of septate junctions". ... Zonula occludens-1 ZO-1, also known as Tight junction protein-1 is a 220-kD peripheral membrane protein that is encoded by the ...
Intercellular gap junctions in vertebrates, including humans, are formed by the connexin family of proteins. Structurally, ... Panchin Y, Kelmanson I, Matz M, Lukyanov K, Usman N, Lukyanov S (June 2000). "A ubiquitous family of putative gap junction ... While innexins are responsible for forming gap junctions in invertebrates, the pannexins have been shown to predominantly exist ... Shestopalov VI, Panchin Y (February 2008). "Pannexins and gap junction protein diversity". Cellular and Molecular Life Sciences ...
Regulation depends on the intercellular tight junctions which have the most influence on paracellular transport. Disruption of ... Most people do not experience adverse symptoms, but the opening of intercellular tight junctions (increased intestinal ... a modulator of intercellular tight junctions. This process takes place in all individuals who ingest gluten. For the majority, ... It is regulated by cellular junctions that are localized in the laminal membranes of the cells. This is the main route of ...
Gap Junction‐Mediated Intercellular Signalling in Health and Disease. Novartis Foundation Symposia. Vol. 219. pp. 60-72, ... For the last 20 years before Warner began her research on gap junctions, embryologists had been working hard to prove that gap ... After confirming the successful blocking of the gap junctions in the 8-cell-embryos, Warner continued to grow the embryos and ... After injecting the embryos with a specific antibody, which was said to have blocked the channels of gap junctions, Warner ...
... a critical scaffold for PKC alpha that regulates intercellular junction assembly". The Journal of Cell Biology. 181 (4): 605-13 ... and mediates crosstalk between intercellular junctions and membrane excitability. Mutations in PKP2 have been associated with, ... "A novel kind of tumor type-characteristic junction: plakophilin-2 as a major protein of adherens junctions in cardiac myxomata ... Plakophilin-2 over time has shown to be more than components of cell-cell junctions; rather the plakophilins are emerging as ...
Gap Junction‐Mediated Intercellular Signalling in Health and Disease. Novartis Foundation Symposia. Vol. 219. pp. 44-54, ... An entirely different family of proteins, the innexins, form gap junctions in invertebrates. Each gap junction is composed of ... Recent studies have shown the existence of communication between adherens junctions and gap junctions, suggesting a higher ... and two hemichannels then combine to form a gap junction. The crystal structure of the gap junction channel formed by human ...
Each gap junction intercellular channel is formed by the conjunction of 2 connexons. See GJB2 for additional background ... Gap junction delta-2 protein (GJD2) also known as connexin-36 (Cx36) or gap junction alpha-9 protein (GJA9) is a protein that ... 2007). "Gap junction coding genes and schizophrenia: a genetic association study". J. Hum. Genet. 52 (6): 498-501. doi:10.1007/ ... Overview of all the structural information available in the PDB for UniProt: Q9UKL4 (Gap junction delta-2 protein) at the PDBe- ...
It is a peptide analog that has been shown to increase gap junction intercellular conductance in cardiac muscle cells. Gap ... Mantz J, Cordier J, Giaume C (1993). Effects of general anesthetics on inter-cellular communications mediated by gap junctions ... increases gap junction intercellular communication in cardiac myocytes and HeLa cells expressing connexin 43. British Journal ... Each gap junction is composed of a series of connexons close to each other. Each connexon is made up of 6 functional units ( ...
1998). "Identification of a novel cadherin (vascular endothelial cadherin-2) located at intercellular junctions in endothelial ...
Rosselló, RA; Kohn, DH (2009). "Gap junction intercellular communication: A review of a potential platform to modulate ...
... malignant epithelial cells lose their apical-basal polarity due to disruption in tight intercellular junctions and loss of ... In this case, there is significant rearrangement of the whole actin-myosin cytoskeleton and loss of E-cadherin intercellular ... migration is characterized by the migration of whole cell groups interconnected by cadherins and intercellular gap junctions. A ... This results in the disruption of strong cadherin junctions and activation of polar cell migration and proteolysis of ...
Pappenheimer JR, Reiss KZ (1987). "Contribution of solvent drag through intercellular junctions to absorption of nutrients by ... Some claudins form tight junction-associated pores that allow paracellular ion transport. The tight junctions have a net ... Tight junctions in the intestinal epithelium are also known to be size-selective, such that large molecules (with molecular ... Anderson JM, Van Itallie CM (August 2009). "Physiology and function of the tight junction". Cold Spring Harbor Perspectives in ...
Intercellular junctions and tubulobulbar complexes between sertoli cells in primary culture and in vivo Sriram, Aarati Abstract ... Massive intercellular junctions form at the base of the epithelium where Sertoli cells are connected to each other, and at the ... Massive intercellular junctions form at the base of the epithelium where Sertoli cells are connected to each other, and at the ... Intercellular junctions and tubulobulbar complexes between sertoli cells in primary culture and in vivo ...
Contact normalization is a process by which intercellular junctions mediate signals that allow normal cells to inhibit the ... In: Kandous, M. (Eds.) Intercellular communication and Cancer. pp. 297-342. Heidelberg: Springer-Verlag. (Cell communication, ...
Intercellular Junctions / pathology* * Intestinal Mucosa / immunology* * Intestinal Mucosa / pathology* Grants and funding * ... The protein networks connecting epithelial cells form 3 adhesive complexes: desmosomes, adherens junctions, and tight junctions ... through the formation of complex protein-protein networks that mechanically link adjacent cells and seal the intercellular ...
Intercellular junctions are present (see the image below). [89] Meningiomas Pathology. Note the interdigitating cytoplasmic ... The intercellular border is typically fuzzy and poorly defined (see the second image below). This feature reflects the ... Arishima H, Sato K, Kubota T. Immunohistochemical and ultrastructural study of gap junction proteins connexin26 and 43 in human ...
Intercellular Junctions [A11.284.149.165.420]. *Synapses [A11.284.149.165.420.780]. *Synaptic Membranes [A11.284.149.165. ...
Astrocyte signaling is primarily mediated by the propagation of intercellular calcium waves (ICW) in the sense that paracrine ... Specifically, we were able to accurately simulate experimentally measured in vitro intercellular calcium wave dynamics by ... Astrocyte signaling is primarily mediated by the propagation of intercellular calcium waves in the sense that paracrine ... Intercellular calcium signaling via gap junctions in glioma cells J. Cell Biol. 118, 195-201. ...
Single-molecular researches on positive mechano-feedback at intercellular adherens junctions. Koichiro Maki (Kyoto Univ.) ...
Endothelial cells have tight junctions between them  Contain intercellular clefts: these allow the limited passage of fluid ...
Intercellular junctions are present (see the image below). [89] Meningiomas Pathology. Note the interdigitating cytoplasmic ... The intercellular border is typically fuzzy and poorly defined (see the second image below). This feature reflects the ... Arishima H, Sato K, Kubota T. Immunohistochemical and ultrastructural study of gap junction proteins connexin26 and 43 in human ...
Resveratrol induces chemosensitization to 5-fluorouracil through up-regulation of intercellular junctions, epithelial-to- ...
The imbalance in intestinal microbiota alters the tight intercellular junctions (TJ) that allow access to pathogens and toxins ... Our gut lining is made up of a barrier of tight junctions, like little doors that open and close to control what gets into our ... Sometimes these tight junctions can become weak or loose, allowing potential pathogens to sneak across the intestinal wall. ... There are some studies suggesting L-glutamine modulates the expression of tight junction proteins. ...
Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states ... Gap junction beta-2 protein. A [auth B],. B [auth A]. 226. Homo sapiens. Mutation(s): 3 Gene Names: GJB2. Membrane Entity: Yes ... An electrostatic mechanism for Ca(2+)-mediated regulation of gap junction channels.. Bennett, B.C., Purdy, M.D., Baker, K.A., ... To explore the mechanism by which Ca(2+) blocks intercellular communication during tissue injury, we determined the X-ray ...
... serves to recruit Par3 to intercellular junctions. For decades, loss of apico-basal polarity has been considered a prerequisite ... Sex-specific control of intercellular crosstalk in the skin * Cell polarity defects and hypotonic stress in epithelial ... Sex-specific control of intercellular crosstalk in the skin * Cell polarity defects and hypotonic stress in epithelial ...
1987) Contribution of solvent drag through intercellular junctions to absorption of nutrients by the small intestine of the rat ... The absorption of OLE can be markedly improved by solvent flux through paracellular junctions, an effect that is facilitated by ... A significant factor stimulating the water flux through the opening of paracellular junctions is the postprandial presence of ...
Oedema resulted in destruction of the intercellular junctions leading to partial or complete loss of cellular adhesion. Areas ... Wide intercellular spaces between the superficial epithelial cells were still apparent (Figure 5). ... The intercellular spaces had started to be repaired with normal architecture (Figure 6). ... causing widening of the intercellular spaces in the deep layers of the CT, and dense, coarse collagen fibres and bundles ...
Nongenomic glucocorticoid receptor action regulates gap junction intercellular communication and neural progenitor cell ...
The intercellular spaces have tight junctions that resist paracellular transport. 26 Lipophilic drugs can di use through the ... The retinal vasculature is lined with endothelial cells bound by tight-junctions to prevent blood borne drugs and pathogens ... The RPE, similarly to the conjunctiva, consists of cell layers bounded by tight junctions. The paracellular transport route is ... It cannot cross the epithelium transcellularly (because of lipid membrane) or paracellularly (because of tight junctions), and ...
sildenafil 100mg intercellular junctions. of new networks of blood vessels.Not infrequently, the reasons of a precociously-. ...
The apical-most epithelial intercellular junction, referred to as the tight junction (TJ), regulates paracellular solute flux ... The last step of cell division, abscission, occurs at an about 1 μm wide intercellular bridge that connects the post-mitotic ... Constitutive activation of Rho proteins by CNF-1 influences tight junction structure and epithelial barrier function.. J Cell ... In contrast to the TJ, the characteristic ring structure of proteins in adherens junctions (AJs) was largely preserved despite ...
The subperineurial glial cells build a diffusion barrier by forming intercellular pleated septate junctions that prevent ...
... possibly by its inclusion in intercellular junctions [68] in the interior of the tumor mass. At this time, the lack of L1 ... Cell adhesion molecule L1 disrupts E-cadherin-containing adheren junctions and increases scattering and motility of MCF7 breast ...
... the inhibition of junction mediated intercellular communication, has not been previously reported. ...
... called intercellular tight junctions, which also have small pores that pass through them. These pores and tight junctions are ... occurred within 2 days of infection and coincided with IL-22-dependent upregulation of the epithelial tight junction protein ...
They may also be involved in the regulation of tight and gap junctions, and in the control of intercellular spacing. Cadherins ... Adherens junctions are specialized forms of cadherin-based adhesive contacts important for tissue organization in developing ... Adherens junctions are likely to serve specific, specialized functions beyond the basic adhesive process. These functions ... Cell-cell adhesion in zonula adherens and desmosomal junctions is mediated by cadherins, and recent crystal structures of the ...
This review describes the functions and mechanisms of the chaperone-assisted regulation of intercellular junctions. The major ... adherens junctions, and a junction-associated cytoskeleton. The establishment of this junction-cytoskeletal module relies on ... Only a small part of this network has been linked, however, to the regulation of intercellular adhesions, and the systematic ... The integrity and permeability of epithelial and endothelial barriers depend on the formation of tight junctions, ...
Intercellular Junctions. Cells can also communicate with each other by direct contact, referred to as intercellular junctions. ... d) Gap junctions act as channels between animal cells.. A tight junction is a watertight seal between two adjacent animal cells ... Gap junctions in animal cells are like plasmodesmata in plant cells in that they are channels between adjacent cells that allow ... Tight junctions are typically found in the epithelial tissue that lines internal organs and cavities, and composes most of the ...
... form asymmetric complexes that bridge apical intercellular junctions. While these can assemble in either orientation, ... Asymmetric homotypic interactions of the atypical cadherin Flamingo mediate intercellular polarity signaling CELL Chen, W., ... The polarity of these structures is preceded by asymmetric localization of PCP signaling proteins at the apical junctions of ... Here, we provide evidence that Fmi functions instructively to mediate Fz-Vang intercellular signal relay, recruiting Fz and ...
  • Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states such as cardiac arrhythmias, cancer and trauma. (rcsb.org)
  • The protein networks connecting epithelial cells form 3 adhesive complexes: desmosomes, adherens junctions, and tight junctions. (nih.gov)
  • Cadherins are a group of transmembrane proteins that serve as the major adhesion molecules located within adherens junctions. (embl.de)
  • Molecular and functional analysis of cadherin-based adherens junctions. (embl.de)
  • Adherens junctions are specialized forms of cadherin-based adhesive contacts important for tissue organization in developing and adult organisms. (embl.de)
  • Adherens junctions are likely to serve specific, specialized functions beyond the basic adhesive process. (embl.de)
  • Tight junction proteins (TJPs) belong to a family of membrane-associated guanylate kinase (MAGUK) homologs that are involved in the organization of epithelial and endothelial intercellular junctions. (genetex.com)
  • The inter-endothelial tight junctions that consist of tight junction proteins are critical regulators of BBB dysfunctions and hyperpermeability. (bvsalud.org)
  • Herein, we have described the protocol for immunoblot analysis of ZO-1 as an indicator of tight junction integrity in brain microvascular endothelial cells. (bvsalud.org)
  • PAR-1 activation strengthens endothelial tight junctions, increases endothelial survival, and dampens the inflammatory response. (cdc.gov)
  • Cadherins are evolutionary related to the desmogleins which are component of intercellular desmosome junctions involved in the interaction of plaque proteins. (embl.de)
  • Most commonly, the mutations affect the component of the disk known as the desmosome (the adhesive intercellular junction that tethers intermediate filaments to cell membranes). (msdmanuals.com)
  • During epithelial cell-cell contact formation, the TJ protein Junctional Adhesion Molecule-A (JAM-A) serves to recruit Par3 to intercellular junctions. (uni-saarland.de)
  • Increased permeability occurred within 2 days of infection and coincided with IL-22-dependent upregulation of the epithelial tight junction protein claudin-2. (inverse.com)
  • The epithelial permeability was evaluated by transepithelial electrical resistance (TEER) assay, and inflammation- and tight junction (TJ)-related protein expression were analyzed by Western blotting. (bvsalud.org)
  • A growing body of evidence indicates that apical TBCs internalize tissue specific adhesion junctions at the apex of the epithelium and are involved in sperm release. (ubc.ca)
  • The major tight junction-associated proteins of the BBB are occludin, claudins, and junctional adhesion molecules that are intracellularly linked to the adaptor protein zonula occludens-1 (ZO-1). (bvsalud.org)
  • The epithelium maintains its selective barrier function through the formation of complex protein-protein networks that mechanically link adjacent cells and seal the intercellular space. (nih.gov)
  • Tubulobulbar complexes (TBCs) are actin-rich structures that form at intercellular junctions in the seminiferous epithelium of the mammalian testis. (ubc.ca)
  • To explore the mechanism by which Ca(2+) blocks intercellular communication during tissue injury, we determined the X-ray crystal structures of the human Cx26 gap junction channel with and without bound Ca(2+). (rcsb.org)
  • Quantitative measurement of tight junction-associated proteins provides valuable insight into barrier integrity and mechanisms that regulate microvascular hyperpermeability. (bvsalud.org)
  • Intercellular junctions and tubulobulbar complexes. (ubc.ca)
  • Intercellular communication and Cancer. (wikipedia.org)
  • This cellular response to arsenic (7440382), mercury (7439976), and lead (7439921), the inhibition of junction mediated intercellular communication, has not been previously reported. (cdc.gov)
  • Massive intercellular junctions form at the base of the epithelium where Sertoli cells are connected to each other, and at the apex where Sertoli cells are connected to mature spermatids. (ubc.ca)
  • In the seminiferous epithelium, if basal TBCs are responsible for internalizing junctions, then interfering with TBC structure or formation should lead to delayed translocation of spermatocytes and increased mass of basal intercellular junctions. (ubc.ca)
  • Three major types of intercellular junctions exist in vertebrates: tight junctions, adherens junctions, and gap junctions [ 11 ]. (hindawi.com)
  • Adherens junctions are formed by cadherins linked to the cytoskeleton by catenin family proteins, and vascular endothelial- (VE-) cadherin is an endothelial specific adherens junction protein [ 13 ]. (hindawi.com)
  • 3. Regulation of the assembly and adhesion activity of E-cadherin by nectin and afadin for the formation of adherens junctions in Madin-Darby canine kidney cells. (nih.gov)
  • 7. ADIP, a novel Afadin- and alpha-actinin-binding protein localized at cell-cell adherens junctions. (nih.gov)
  • 10. Role of nectin in formation of E-cadherin-based adherens junctions in keratinocytes: analysis with the N-cadherin dominant negative mutant. (nih.gov)
  • 12. Nectin/PRR: an immunoglobulin-like cell adhesion molecule recruited to cadherin-based adherens junctions through interaction with Afadin, a PDZ domain-containing protein. (nih.gov)
  • 18. Involvement of heterophilic trans-interaction of Necl-5/Tage4/PVR/CD155 with nectin-3 in formation of nectin- and cadherin-based adherens junctions. (nih.gov)
  • Cadherins are a group of transmembrane proteins that serve as the major adhesion molecules located within adherens junctions. (embl.de)
  • Molecular and functional analysis of cadherin-based adherens junctions. (embl.de)
  • Adherens junctions are specialized forms of cadherin-based adhesive contacts important for tissue organization in developing and adult organisms. (embl.de)
  • Adherens junctions are likely to serve specific, specialized functions beyond the basic adhesive process. (embl.de)
  • Platelet endothelial cell adhesion molecule-1 (PECAM-1) is a 130-kDa member of the immunoglobulin gene superfamily (IgSF) that is present on the surface of circulating platelets and leukocytes, and highly expressed at the junctions of confluent endothelial cell monolayers. (nih.gov)
  • PECAM-1-mediated homophilic interactions, known to be mediated by its 2 amino-terminal immunoglobulin homology domains, are essential for concentrating PECAM-1 at endothelial cell intercellular junctions, where it functions to facilitate diapedesis, maintain vascular integrity, and transmit survival signals into the cell. (nih.gov)
  • Caco-2 cells labeled for tight junction molecule cingulin (green), actin (red), vinculin (pink) and DNA (blue). (weizmann.ac.il)
  • Connexins compose the gap junction channels [ 14 ], and connexin 40 was found highly expressed in endothelial cells [ 15 , 16 ]. (hindawi.com)
  • These structures form junctions that attach cells to one another. (medlineplus.gov)
  • 5. Nectin-dependent localization of ZO-1 at puncta adhaerentia junctions between the mossy fiber terminals and the dendrites of the pyramidal cells in the CA3 area of adult mouse hippocampus. (nih.gov)
  • 9. Requirement of the actin cytoskeleton for the association of nectins with other cell adhesion molecules at adherens and tight junctions in MDCK cells. (nih.gov)
  • 11. Nectin-dependent localization of synaptic scaffolding molecule (S-SCAM) at the puncta adherentia junctions formed between the mossy fibre terminals and the dendrites of pyramidal cells in the CA3 area of the mouse hippocampus. (nih.gov)
  • 17. Involvement of the interaction of afadin with ZO-1 in the formation of tight junctions in Madin-Darby canine kidney cells. (nih.gov)
  • CD146 is expressed at cell-cell junctions in all endothelial cells, and has also been observed in other normal and malignant cell types. (thermofisher.com)
  • The total number of dye positive adjacent cells were used as an indication of gap junction intercellular communication. (cdc.gov)
  • Gap junctions are membrane channels formed by an array of connexins which links adjacent cells realizing an electro- metabolic synapse. (biomedcentral.com)
  • The passage of ions and small molecular weight molecules through gap junction channels results in metabolic and electrical coupling of cells thus allowing rapid intercellular communication and synchronization of cell activities. (biomedcentral.com)
  • EMT enables the carcinoma cells to overcome physical barrier imposed by intercellular junctions 7 . (cancertreatmentjournal.com)
  • The decreased transendothelial electrical resistance (TEER), increased permeability, and disruption of cellular junctions were observed in HUVECs after gamma irradiation accompanied by the lower levels of junction-related proteins such as ZO-1, occludin, vascular endothelial- (VE-) cadherin, and connexin 40. (hindawi.com)
  • HPCs were distributed three-dimensionally inside this MSC network and formed ß-catenin- and N-cadherin-based intercellular junctions to the surrounding MSCs. (kit.edu)
  • He did postdoctoral research on membrane structure and intercellular junctions with Pedro Pinto da Silva at the National Cancer Institute, and on cell structure and motility with Thomas Reese at the National Institute of Neurological Disorders and Stroke. (nih.gov)
  • Most such junctions are too small to be resolved by light microscopy, but they can be visualized by conventional or freeze-fracture electron microscopy, both of which show that the interacting CELL MEMBRANE and often the underlying CYTOPLASM and the intervening EXTRACELLULAR SPACE are highly specialized in these regions. (bvsalud.org)
  • The effect of asphalt fume condensate fractions on gap junctional intercellular communication in a human epidermal keratinocyte cell line was investigated. (cdc.gov)
  • We investigated the transcription and protein expression of connexin-43 and the gap-junctional intercellular communication (GJIC) in 5 primary lung fibroblast lines derived from normal subjects (NF) and from 3 histologically proven IPF patients (FF). (biomedcentral.com)
  • Inhibition of intercellular communication in human keratinocytes by fractionated asphalt fume condensates. (cdc.gov)
  • The endothelial integrity is closely associated with the barrier functions of intercellular junctions. (hindawi.com)
  • Tight junctions are essential for epithelial and endothelial barrier formation. (mdpi.com)
  • These included an increase in the prominence of intercellular junctions and the formation of folds and microvilli. (cdc.gov)
  • The behavior of a phosphorylation-deficient DP mutant that associates more tightly with IF is mimicked by PKP2 and PKC alpha knockdown and PKC pharmacological inhibition, all of which impair junction assembly. (nih.gov)
  • All the fractions demonstrated a concentration dependent inhibition of dye coupling, indicating an inhibition in gap junction intercellular communication. (cdc.gov)
  • The authors conclude that fractionated asphalt fume condensates may have tumor promoting activity by inducing an inhibition of gap junction intercellular communication. (cdc.gov)
  • Krystofiak ES, Heymann JB, Kachar B. Carbon replicas reveal double stranded structure of tight junctions in phase-contrast electron microscopy . (nih.gov)
  • Occludin and claudin-5 are the fundamental transmembrane proteins in the formation of tight junctions and connect to the cytoskeleton through the ZO family [ 12 ]. (hindawi.com)
  • They may also be involved in the regulation of tight and gap junctions, and in the control of intercellular spacing. (embl.de)
  • Zhao J, Krystofiak ES, Ballesteros A, Cui R, Van Itallie CM, Anderson JM, Fenollar-Ferrer C, Kachar B. Multiple claudin-claudin cis interfaces are required for tight junction strand formation and inherent flexibility . (nih.gov)
  • Consequently, tight junctions and their components have been linked to multiple inherited, acute, and chronic diseases such as cancer, viral infections, and inflammatory and degenerative conditions. (mdpi.com)
  • The purpose of this Special Issue on the structure and function of tight junctions is to emphasize and discuss recent findings on how tight junctions assemble and function in different cell types, and their role in tissue development and morphogenetic processes. (mdpi.com)
  • In order to demonstrate that dye spreading was taking place through gap junctions, we used carbenoxolone as a pharmacological gap-junction blocker. (biomedcentral.com)
  • 8. Different behavior of l-afadin and neurabin-II during the formation and destruction of cell-cell adherens junction. (nih.gov)
  • There are increasing evidences indicating the altered intercellular junction function induced by gamma radiation exposure [ 11 , 12 , 17 ]. (hindawi.com)
  • We sought to evaluate the role of connexin-43, the most abundant gap-junction subunit in the human lung, in the pathogenesis of this condition. (biomedcentral.com)