Integrin beta3
Integrin beta4
Also known as CD104 antigen, this protein is distinguished from other beta integrins by its relatively long cytoplasmic domain (approximately 1000 amino acids vs. approximately 50). Five alternatively spliced isoforms have been described.
Integrin beta Chains
Integrin beta chains combine with integrin alpha chains to form heterodimeric cell surface receptors. Integrins have traditionally been classified into functional groups based on the identity of one of three beta chains present in the heterodimer. The beta chain is necessary and sufficient for integrin-dependent signaling. Its short cytoplasmic tail contains sequences critical for inside-out signaling.
Antigens, CD29
Integrin beta-1 chains which are expressed as heterodimers that are noncovalently associated with specific alpha-chains of the CD49 family (CD49a-f). CD29 is expressed on resting and activated leukocytes and is a marker for all of the very late activation antigens on cells. (from: Barclay et al., The Leukocyte Antigen FactsBook, 1993, p164)
Integrins
A family of transmembrane glycoproteins (MEMBRANE GLYCOPROTEINS) consisting of noncovalent heterodimers. They interact with a wide variety of ligands including EXTRACELLULAR MATRIX PROTEINS; COMPLEMENT, and other cells, while their intracellular domains interact with the CYTOSKELETON. The integrins consist of at least three identified families: the cytoadhesin receptors(RECEPTORS, CYTOADHESIN), the leukocyte adhesion receptors (RECEPTORS, LEUKOCYTE ADHESION), and the VERY LATE ANTIGEN RECEPTORS. Each family contains a common beta-subunit (INTEGRIN BETA CHAINS) combined with one or more distinct alpha-subunits (INTEGRIN ALPHA CHAINS). These receptors participate in cell-matrix and cell-cell adhesion in many physiologically important processes, including embryological development; HEMOSTASIS; THROMBOSIS; WOUND HEALING; immune and nonimmune defense mechanisms; and oncogenic transformation.
Integrin alphaVbeta3
An integrin that binds to a variety of plasma and extracellular matrix proteins containing the conserved RGD amino acid sequence and modulates cell adhesion. Integrin alphavbeta3 is highly expressed in OSTEOCLASTS where it may play role in BONE RESORPTION. It is also abundant in vascular smooth muscle and endothelial cells, and in some tumor cells, where it is involved in angiogenesis and cell migration. Although often referred to as the vitronectin receptor there is more than one receptor for vitronectin (RECEPTORS, VITRONECTIN).
Integrin alpha5beta1
An integrin found in FIBROBLASTS; PLATELETS; MONOCYTES, and LYMPHOCYTES. Integrin alpha5beta1 is the classical receptor for FIBRONECTIN, but it also functions as a receptor for LAMININ and several other EXTRACELLULAR MATRIX PROTEINS.
Integrin alpha6beta4
This intrgrin is a key component of HEMIDESMOSOMES and is required for their formation and maintenance in epithelial cells. Integrin alpha6beta4 is also found on thymocytes, fibroblasts, and Schwann cells, where it functions as a laminin receptor (RECEPTORS, LAMININ) and is involved in wound healing, cell migration, and tumor invasiveness.
Integrin alpha5
This integrin alpha subunit combines with INTEGRIN BETA1 to form a receptor (INTEGRIN ALPHA5BETA1) that binds FIBRONECTIN and LAMININ. It undergoes posttranslational cleavage into a heavy and a light chain that are connected by disulfide bonds.
Integrin alpha6
An integrin alpha subunit that primarily associates with INTEGRIN BETA1 or INTEGRIN BETA4 to form laminin-binding heterodimers. Integrin alpha6 has two alternatively spliced isoforms: integrin alpha6A and integrin alpha6B, which differ in their cytoplasmic domains and are regulated in a tissue-specific and developmental stage-specific manner.
Integrin alpha Chains
The alpha subunits of integrin heterodimers (INTEGRINS), which mediate ligand specificity. There are approximately 18 different alpha chains, exhibiting great sequence diversity; several chains are also spliced into alternative isoforms. They possess a long extracellular portion (1200 amino acids) containing a MIDAS (metal ion-dependent adhesion site) motif, and seven 60-amino acid tandem repeats, the last 4 of which form EF HAND MOTIFS. The intracellular portion is short with the exception of INTEGRIN ALPHA4.
Integrin alphaV
An alpha integrin with a molecular weight of 160-kDa that is found in a variety of cell types. It undergoes posttranslational cleavage into a heavy and a light chain that are connected by disulfide bonds. Integrin alphaV can combine with several different beta subunits to form heterodimers that generally bind to RGD sequence-containing extracellular matrix proteins.
Integrin alpha3beta1
Cell surface receptor for LAMININ, epiligrin, FIBRONECTINS, entactin, and COLLAGEN. Integrin alpha3beta1 is the major integrin present in EPITHELIAL CELLS, where it plays a role in the assembly of BASEMENT MEMBRANE as well as in cell migration, and may regulate the functions of other integrins. Two alternatively spliced isoforms of the alpha subunit (INTEGRIN ALPHA3), are differentially expressed in different cell types.
Integrin alpha2
An integrin alpha subunit that primarily combines with INTEGRIN BETA1 to form the INTEGRIN ALPHA2BETA1 heterodimer. It contains a domain which has homology to collagen-binding domains found in von Willebrand factor.
Integrin alpha2beta1
An integrin found on fibroblasts, platelets, endothelial and epithelial cells, and lymphocytes where it functions as a receptor for COLLAGEN and LAMININ. Although originally referred to as the collagen receptor, it is one of several receptors for collagen. Ligand binding to integrin alpha2beta1 triggers a cascade of intracellular signaling, including activation of p38 MAP kinase.
Integrin alpha4
Integrin alpha6beta1
A cell surface receptor mediating cell adhesion to the EXTRACELLULAR MATRIX and to other cells via binding to LAMININ. It is involved in cell migration, embryonic development, leukocyte activation and tumor cell invasiveness. Integrin alpha6beta1 is the major laminin receptor on PLATELETS; LEUKOCYTES; and many EPITHELIAL CELLS, and ligand binding may activate a number of signal transduction pathways. Alternative splicing of the cytoplasmic domain of the alpha6 subunit (INTEGRIN ALPHA6) results in the formation of A and B isoforms of the heterodimer, which are expressed in a tissue-specific manner.
Talin
A 235-kDa cytoplasmic protein that is also found in platelets. It has been localized to regions of cell-substrate adhesion. It binds to INTEGRINS; VINCULIN; and ACTINS and appears to participate in generating a transmembrane connection between the extracellular matrix and the cytoskeleton.
Integrin alpha3
An integrin alpha subunit that occurs as alternatively spliced isoforms. The isoforms are differentially expressed in specific cell types and at specific developmental stages. Integrin alpha3 combines with INTEGRIN BETA1 to form INTEGRIN ALPHA3BETA1 which is a heterodimer found primarily in epithelial cells.
Integrin alpha1
An integrin alpha subunit that binds COLLAGEN and LAMININ though its I domain. It combines with INTEGRIN BETA1 to form the heterodimer INTEGRIN ALPHA1BETA1.
Integrin alpha1beta1
Integrin alpha1beta1 functions as a receptor for LAMININ and COLLAGEN. It is widely expressed during development, but in the adult is the predominant laminin receptor (RECEPTORS, LAMININ) in mature SMOOTH MUSCLE CELLS, where it is important for maintenance of the differentiated phenotype of these cells. Integrin alpha1beta1 is also found in LYMPHOCYTES and microvascular endothelial cells, and may play a role in angiogenesis. In SCHWANN CELLS and neural crest cells, it is involved in cell migration. Integrin alpha1beta1 is also known as VLA-1 and CD49a-CD29.
Receptors, Vitronectin
Receptors such as INTEGRIN ALPHAVBETA3 that bind VITRONECTIN with high affinity and play a role in cell migration. They also bind FIBRINOGEN; VON WILLEBRAND FACTOR; osteopontin; and THROMBOSPONDINS.
Fibronectins
Glycoproteins found on the surfaces of cells, particularly in fibrillar structures. The proteins are lost or reduced when these cells undergo viral or chemical transformation. They are highly susceptible to proteolysis and are substrates for activated blood coagulation factor VIII. The forms present in plasma are called cold-insoluble globulins.
Cell Movement
The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.
Hemidesmosomes
An anchoring junction of the cell to a non-cellular substrate, similar in morphology to halves of DESMOSOMES. They are composed of specialized areas of the plasma membrane where INTERMEDIATE FILAMENTS bind on the cytoplasmic face to the transmembrane linkers, INTEGRINS, via intracellular attachment proteins, while the extracellular domain of the integrins binds to EXTRACELLULAR MATRIX PROTEINS.
Antigens, CD18
Interleukin-1beta
An interleukin-1 subtype that is synthesized as an inactive membrane-bound pro-protein. Proteolytic processing of the precursor form by CASPASE 1 results in release of the active form of interleukin-1beta from the membrane.
Laminin
Large, noncollagenous glycoprotein with antigenic properties. It is localized in the basement membrane lamina lucida and functions to bind epithelial cells to the basement membrane. Evidence suggests that the protein plays a role in tumor invasion.
Signal Transduction
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.
Molecular Sequence Data
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.
Platelet Glycoprotein GPIIb-IIIa Complex
Platelet membrane glycoprotein complex important for platelet adhesion and aggregation. It is an integrin complex containing INTEGRIN ALPHAIIB and INTEGRIN BETA3 which recognizes the arginine-glycine-aspartic acid (RGD) sequence present on several adhesive proteins. As such, it is a receptor for FIBRINOGEN; VON WILLEBRAND FACTOR; FIBRONECTIN; VITRONECTIN; and THROMBOSPONDINS. A deficiency of GPIIb-IIIa results in GLANZMANN THROMBASTHENIA.
Cells, Cultured
Amino Acid Sequence
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.
Extracellular Matrix
A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere.
Antigens, CD
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.
beta 2-Microglobulin
An 11-kDa protein associated with the outer membrane of many cells including lymphocytes. It is the small subunit of the MHC class I molecule. Association with beta 2-microglobulin is generally required for the transport of class I heavy chains from the endoplasmic reticulum to the cell surface. Beta 2-microglobulin is present in small amounts in serum, csf, and urine of normal people, and to a much greater degree in the urine and plasma of patients with tubular proteinemia, renal failure, or kidney transplants.
Vitronectin
A blood plasma glycoprotein that mediates cell adhesion and interacts with proteins of the complement, coagulation, and fibrinolytic cascade. (From Segen, Dictionary of Modern Medicine, 1992)
Receptors, Fibronectin
Specific cell surface receptors which bind to FIBRONECTINS. Studies have shown that these receptors function in certain types of adhesive contact as well as playing a major role in matrix assembly. These receptors include the traditional fibronectin receptor, also called INTEGRIN ALPHA5BETA1 and several other integrins.
Focal Adhesion Protein-Tyrosine Kinases
A family of non-receptor, PROLINE-rich protein-tyrosine kinases.
Platelet Membrane Glycoproteins
Cytoplasm
Cell Adhesion Molecules
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.
Protein Binding
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.
Focal Adhesion Kinase 1
A non-receptor protein tyrosine kinase that is localized to FOCAL ADHESIONS and is a central component of integrin-mediated SIGNAL TRANSDUCTION PATHWAYS. Focal adhesion kinase 1 interacts with PAXILLIN and undergoes PHOSPHORYLATION in response to adhesion of cell surface integrins to the EXTRACELLULAR MATRIX. Phosphorylated p125FAK protein binds to a variety of SH2 DOMAIN and SH3 DOMAIN containing proteins and helps regulate CELL ADHESION and CELL MIGRATION.
CHO Cells
CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.
Filamins
A family of crosslinking filament proteins encoded by distinct FLN genes. Filamins are involved in cell adhesion, spreading, and migration, acting as scaffolds for over 90 binding partners including channels, receptors, intracellular signaling molecules and transcription factors. Due to the range of molecular interactions, mutations in FLN genes result in anomalies with moderate to lethal consequences.
Phosphorylation
Cricetinae
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
Focal Adhesions
An anchoring junction of the cell to a non-cellular substrate. It is composed of a specialized area of the plasma membrane where bundles of the ACTIN CYTOSKELETON terminate and attach to the transmembrane linkers, INTEGRINS, which in turn attach through their extracellular domains to EXTRACELLULAR MATRIX PROTEINS.
Transfection
Plectin
A cytoskeletal linker protein with a molecular weight of greater than 500 kDa. It binds INTERMEDIATE FILAMENTS; MICROTUBULES; and ACTIN CYTOSKELETON and plays a central role in the organization and stability of the CYTOSKELETON. Plectin is phosphorylated by CALMODULIN KINASE; PROTEIN KINASE A; and PROTEIN KINASE C.
Cell Line, Tumor
A cell line derived from cultured tumor cells.
Receptors, Adrenergic, beta
Transforming Growth Factor beta
A factor synthesized in a wide variety of tissues. It acts synergistically with TGF-alpha in inducing phenotypic transformation and can also act as a negative autocrine growth factor. TGF-beta has a potential role in embryonal development, cellular differentiation, hormone secretion, and immune function. TGF-beta is found mostly as homodimer forms of separate gene products TGF-beta1, TGF-beta2 or TGF-beta3. Heterodimers composed of TGF-beta1 and 2 (TGF-beta1.2) or of TGF-beta2 and 3 (TGF-beta2.3) have been isolated. The TGF-beta proteins are synthesized as precursor proteins.
Ligands
A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)
Receptors, Collagen
Collagen receptors are cell surface receptors that modulate signal transduction between cells and the EXTRACELLULAR MATRIX. They are found in many cell types and are involved in the maintenance and regulation of cell shape and behavior, including PLATELET ACTIVATION and aggregation, through many different signaling pathways and differences in their affinities for collagen isoforms. Collagen receptors include discoidin domain receptors, INTEGRINS, and glycoprotein VI.
Protein Structure, Tertiary
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Fibrinogen
Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides A and B, the proteolytic action of other enzymes yields different fibrinogen degradation products.
Receptors, Laminin
Glycoprotein molecules on the surface of cells that react with or bind to laminin whose function allows the binding of epithelial cells to the basement membrane. The molecular weight of this high-affinity receptor is 67 kD.
Binding Sites
Thrombasthenia
A congenital bleeding disorder with prolonged bleeding time, absence of aggregation of platelets in response to most agents, especially ADP, and impaired or absent clot retraction. Platelet membranes are deficient in or have a defect in the glycoprotein IIb-IIIa complex (PLATELET GLYCOPROTEIN GPIIB-IIIA COMPLEX).
Collagen
A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).
Flow Cytometry
Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.
Cytoskeleton
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
Base Sequence
RNA, Messenger
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Integrin alphaXbeta2
Clot Retraction
Retraction of a clot resulting from contraction of PLATELET pseudopods attached to FIBRIN strands. The retraction is dependent on the contractile protein thrombosthenin. Clot retraction is used as a measure of platelet function.
RNA, Small Interfering
Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.
Tumor Cells, Cultured
Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.
Paxillin
Paxillin is a signal transducing adaptor protein that localizes to FOCAL ADHESIONS via its four LIM domains. It undergoes PHOSPHORYLATION in response to integrin-mediated CELL ADHESION, and interacts with a variety of proteins including VINCULIN; FOCAL ADHESION KINASE; PROTO-ONCOGENE PROTEIN PP60(C-SRC); and PROTO-ONCOGENE PROTEIN C-CRK.
Precipitin Tests
Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.
Platelet Membrane Glycoprotein IIb
Platelet membrane glycoprotein IIb is an integrin alpha subunit that heterodimerizes with INTEGRIN BETA3 to form PLATELET GLYCOPROTEIN GPIIB-IIIA COMPLEX. It is synthesized as a single polypeptide chain which is then postranslationally cleaved and processed into two disulfide-linked subunits of approximately 18 and 110 kDa in size.
Lymphocyte Function-Associated Antigen-1
An integrin heterodimer widely expressed on cells of hematopoietic origin. CD11A ANTIGEN comprises the alpha chain and the CD18 antigen (ANTIGENS, CD18) the beta chain. Lymphocyte function-associated antigen-1 is a major receptor of T-CELLS; B-CELLS; and GRANULOCYTES. It mediates the leukocyte adhesion reactions underlying cytolytic conjugate formation, helper T-cell interactions, and antibody-dependent killing by NATURAL KILLER CELLS and granulocytes. Intracellular adhesion molecule-1 has been defined as a ligand for lymphocyte function-associated antigen-1.
Blotting, Western
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.
src-Family Kinases
A PROTEIN-TYROSINE KINASE family that was originally identified by homology to the Rous sarcoma virus ONCOGENE PROTEIN PP60(V-SRC). They interact with a variety of cell-surface receptors and participate in intracellular signal transduction pathways. Oncogenic forms of src-family kinases can occur through altered regulation or expression of the endogenous protein and by virally encoded src (v-src) genes.
Mice, Knockout
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.
Fluorescent Antibody Technique
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.
Blood Platelets
Vinculin
A cytoskeletal protein associated with cell-cell and cell-matrix interactions. The amino acid sequence of human vinculin has been determined. The protein consists of 1066 amino acid residues and its gene has been assigned to chromosome 10.
Recombinant Fusion Proteins
rac1 GTP-Binding Protein
A rac GTP-binding protein involved in regulating actin filaments at the plasma membrane. It controls the development of filopodia and lamellipodia in cells and thereby influences cellular motility and adhesion. It is also involved in activation of NADPH OXIDASE. This enzyme was formerly listed as EC 3.6.1.47.
Cell Proliferation
All of the processes involved in increasing CELL NUMBER including CELL DIVISION.
Cell Differentiation
Down-Regulation
A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.
Mutation
Antibodies
Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).
Contractile Proteins
Proteins which participate in contractile processes. They include MUSCLE PROTEINS as well as those found in other cells and tissues. In the latter, these proteins participate in localized contractile events in the cytoplasm, in motile activity, and in cell aggregation phenomena.
Epithelial Cells
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.
Mice, Inbred C57BL
Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.
Reverse Transcriptase Polymerase Chain Reaction
Macromolecular Substances
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
Macrophage-1 Antigen
Immunohistochemistry
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Gene Expression Regulation
Extracellular Matrix Proteins
Macromolecular organic compounds that contain carbon, hydrogen, oxygen, nitrogen, and usually, sulfur. These macromolecules (proteins) form an intricate meshwork in which cells are embedded to construct tissues. Variations in the relative types of macromolecules and their organization determine the type of extracellular matrix, each adapted to the functional requirements of the tissue. The two main classes of macromolecules that form the extracellular matrix are: glycosaminoglycans, usually linked to proteins (proteoglycans), and fibrous proteins (e.g., COLLAGEN; ELASTIN; FIBRONECTINS; and LAMININ).
Gene Expression
Fibroblasts
Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.
Sequence Homology, Amino Acid
Cytoskeletal Proteins
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.
Up-Regulation
A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.
Protein Conformation
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Enzyme Activation
Cell Membrane
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Epidermolysis Bullosa, Junctional
Form of epidermolysis bullosa having onset at birth or during the neonatal period and transmitted through autosomal recessive inheritance. It is characterized by generalized blister formation, extensive denudation, and separation and cleavage of the basal cell plasma membranes from the basement membrane.
Protein-Tyrosine Kinases
Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.
Peptide Fragments
Actins
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.
Protein Subunits
Endothelial Cells
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.
RNA Interference
A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.
Keratinocytes
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.
Microscopy, Fluorescence
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.
beta 2-Glycoprotein I
A 44-kDa highly glycosylated plasma protein that binds phospholipids including CARDIOLIPIN; APOLIPOPROTEIN E RECEPTOR; membrane phospholipids, and other anionic phospholipid-containing moieties. It plays a role in coagulation and apoptotic processes. Formerly known as apolipoprotein H, it is an autoantigen in patients with ANTIPHOSPHOLIPID ANTIBODIES.
Models, Biological
Cricetulus
Platelet Adhesiveness
The process whereby PLATELETS adhere to something other than platelets, e.g., COLLAGEN; BASEMENT MEMBRANE; MICROFIBRILS; or other "foreign" surfaces.
Membrane Proteins
Endothelium, Vascular
Amino Acid Motifs
Integrin alpha4beta1
Integrin alpha4beta1 is a FIBRONECTIN and VCAM-1 receptor present on LYMPHOCYTES; MONOCYTES; EOSINOPHILS; NK CELLS and thymocytes. It is involved in both cell-cell and cell- EXTRACELLULAR MATRIX adhesion and plays a role in INFLAMMATION, hematopoietic cell homing and immune function, and has been implicated in skeletal MYOGENESIS; NEURAL CREST migration and proliferation, lymphocyte maturation and morphogenesis of the PLACENTA and HEART.
Models, Molecular
Cloning, Molecular
Tyrosine
DNA Primers
Phenotype
DNA, Complementary
Receptors, Adrenergic, beta-2
A subclass of beta-adrenergic receptors (RECEPTORS, ADRENERGIC, BETA). The adrenergic beta-2 receptors are more sensitive to EPINEPHRINE than to NOREPINEPHRINE and have a high affinity for the agonist TERBUTALINE. They are widespread, with clinically important roles in SKELETAL MUSCLE; LIVER; and vascular, bronchial, gastrointestinal, and genitourinary SMOOTH MUSCLE.
Collagen Type I
Immunoprecipitation
The aggregation of soluble ANTIGENS with ANTIBODIES, alone or with antibody binding factors such as ANTI-ANTIBODIES or STAPHYLOCOCCAL PROTEIN A, into complexes large enough to fall out of solution.
Mutagenesis, Site-Directed
Neoplasm Metastasis
Immunoblotting
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.
Dose-Response Relationship, Drug
Antigens, CD151
Tetraspanin proteins found associated with LAMININ-binding INTEGRINS. The CD151 antigens may play a role in the regulation of CELL MOTILITY.
Platelet Aggregation
The attachment of PLATELETS to one another. This clumping together can be induced by a number of agents (e.g., THROMBIN; COLLAGEN) and is part of the mechanism leading to the formation of a THROMBUS.
Neoplasm Micrometastasis
Interleukin-1
A soluble factor produced by MONOCYTES; MACROPHAGES, and other cells which activates T-lymphocytes and potentiates their response to mitogens or antigens. Interleukin-1 is a general term refers to either of the two distinct proteins, INTERLEUKIN-1ALPHA and INTERLEUKIN-1BETA. The biological effects of IL-1 include the ability to replace macrophage requirements for T-cell activation.
Platelet Activation
COS Cells
CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)
Osteopontin
A negatively-charged extracellular matrix protein that plays a role in the regulation of BONE metabolism and a variety of other biological functions. Cell signaling by osteopontin may occur through a cell adhesion sequence that recognizes INTEGRIN ALPHA-V BETA-3.
Intercellular Adhesion Molecule-1
Cell Division
The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.
Receptors, Very Late Antigen
Members of the integrin family appearing late after T-cell activation. They are a family of proteins initially identified at the surface of stimulated T-cells, but now identified on a variety of cell types. At least six VLA antigens have been identified as heterodimeric adhesion receptors consisting of a single common beta-subunit and different alpha-subunits.
Subcommissural Organ
Myofibroblasts
Spindle-shaped cells with characteristic CONTRACTILE PROTEINS and structures that contribute to the WOUND HEALING process. They occur in GRANULATION TISSUE and also in pathological processes such as FIBROSIS.
Safrole
Cell Survival
Desmosomes
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)
Crk-Associated Substrate Protein
Crk-associated substrate was originally identified as a highly phosphorylated 130 kDa protein that associates with ONCOGENE PROTEIN CRK and ONCOGENE PROTEIN SRC. It is a signal transducing adaptor protein that undergoes tyrosine PHOSPHORYLATION in signaling pathways that regulate CELL MIGRATION and CELL PROLIFERATION.
Basement Membrane
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.
Mice, Transgenic
Protein Isoforms
Microfilament Proteins
Carrier Proteins
Apoptosis
One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.
Microscopy, Confocal
Calpain
Cysteine proteinase found in many tissues. Hydrolyzes a variety of endogenous proteins including NEUROPEPTIDES; CYTOSKELETAL PROTEINS; proteins from SMOOTH MUSCLE; CARDIAC MUSCLE; liver; platelets; and erythrocytes. Two subclasses having high and low calcium sensitivity are known. Removes Z-discs and M-lines from myofibrils. Activates phosphorylase kinase and cyclic nucleotide-independent protein kinase. This enzyme was formerly listed as EC 3.4.22.4.
Peptides
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Gene Expression Regulation, Neoplastic
Polymerase Chain Reaction
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
Receptors, Adrenergic, beta-1
A subclass of beta-adrenergic receptors (RECEPTORS, ADRENERGIC, BETA). The adrenergic beta-1 receptors are equally sensitive to EPINEPHRINE and NOREPINEPHRINE and bind the agonist DOBUTAMINE and the antagonist METOPROLOL with high affinity. They are found in the HEART, juxtaglomerular cells, and in the central and peripheral nervous systems.
Extracellular Signal-Regulated MAP Kinases
A mitogen-activated protein kinase subfamily that is widely expressed and plays a role in regulation of MEIOSIS; MITOSIS; and post mitotic functions in differentiated cells. The extracellular signal regulated MAP kinases are regulated by a broad variety of CELL SURFACE RECEPTORS and can be activated by certain CARCINOGENS.
Glycogen Synthase Kinase 3
A glycogen synthase kinase that was originally described as a key enzyme involved in glycogen metabolism. It regulates a diverse array of functions such as CELL DIVISION, microtubule function and APOPTOSIS.
Epithelium
One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.
Skin
Receptors, Cytoadhesin
A group of INTEGRINS that includes the platelet outer membrane glycoprotein GPIIb-IIIa (PLATELET GLYCOPROTEIN GPIIB-IIIA COMPLEX) and the vitronectin receptor (RECEPTORS, VITRONECTIN). They play a major role in cell adhesion and serve as receptors for fibronectin, von Willebrand factor, and vitronectin.
Amino Acid Substitution
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
Proto-Oncogene Proteins c-akt
A protein-serine-threonine kinase that is activated by PHOSPHORYLATION in response to GROWTH FACTORS or INSULIN. It plays a major role in cell metabolism, growth, and survival as a core component of SIGNAL TRANSDUCTION. Three isoforms have been described in mammalian cells.
Structure-Activity Relationship
Phosphatidylinositol 3-Kinases
Phosphotransferases that catalyzes the conversion of 1-phosphatidylinositol to 1-phosphatidylinositol 3-phosphate. Many members of this enzyme class are involved in RECEPTOR MEDIATED SIGNAL TRANSDUCTION and regulation of vesicular transport with the cell. Phosphatidylinositol 3-Kinases have been classified both according to their substrate specificity and their mode of action within the cell.
Vascular Cell Adhesion Molecule-1
Cytokine-induced cell adhesion molecule present on activated endothelial cells, tissue macrophages, dendritic cells, bone marrow fibroblasts, myoblasts, and myotubes. It is important for the recruitment of leukocytes to sites of inflammation. (From Pigott & Power, The Adhesion Molecule FactsBook, 1993, p154)
Sequence Alignment
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Phosphoproteins
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.
Mice, Nude
Anoikis
APOPTOSIS triggered by loss of contact with the EXTRACELLULAR MATRIX.
Epitopes
Sites on an antigen that interact with specific antibodies.
Antigens, Surface
Receptors, Cell Surface
Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.
Blotting, Northern
Protein-Serine-Threonine Kinases
A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.
Cadherins
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.
Electrophoresis, Polyacrylamide Gel
Proline
A non-essential amino acid that is synthesized from GLUTAMIC ACID. It is an essential component of COLLAGEN and is important for proper functioning of joints and tendons.
Grooming
Estrogen Receptor beta
Phosphotyrosine
An amino acid that occurs in endogenous proteins. Tyrosine phosphorylation and dephosphorylation plays a role in cellular signal transduction and possibly in cell growth control and carcinogenesis.
Chemotaxis
3T3 Cells
Cell lines whose original growing procedure consisted being transferred (T) every 3 days and plated at 300,000 cells per plate (J Cell Biol 17:299-313, 1963). Lines have been developed using several different strains of mice. Tissues are usually fibroblasts derived from mouse embryos but other types and sources have been developed as well. The 3T3 lines are valuable in vitro host systems for oncogenic virus transformation studies, since 3T3 cells possess a high sensitivity to CONTACT INHIBITION.
Transforming Growth Factor beta1
A subtype of transforming growth factor beta that is synthesized by a wide variety of cells. It is synthesized as a precursor molecule that is cleaved to form mature TGF-beta 1 and TGF-beta1 latency-associated peptide. The association of the cleavage products results in the formation a latent protein which must be activated to bind its receptor. Defects in the gene that encodes TGF-beta1 are the cause of CAMURATI-ENGELMANN SYNDROME.