A member of the annexin family that is a substrate for a tyrosine kinase, ONCOGENE PROTEIN PP60(V-SRC). Annexin A2 occurs as a 36-KDa monomer and in a 90-KDa complex containing two subunits of annexin A2 and two subunits of S100 FAMILY PROTEIN P11. The monomeric form of annexin A2 was formerly referred to as calpactin I heavy chain.
Protein of the annexin family exhibiting lipid interaction and steroid-inducibility.
A protein of the annexin family isolated from human PLACENTA and other tissues. It inhibits cytosolic PHOSPHOLIPASE A2, and displays anticoagulant activity.
Protein of the annexin family with a probable role in exocytotic and endocytotic membrane events.
Protein of the annexin family originally isolated from the electric organ of the electric ray Torpedo marmorata. It has been found in a wide range of mammalian tissue where it is localized to the apical membrane of polarized EPITHELIAL CELLS.
An annexin family member that plays a role in MEMBRANE FUSION and signaling via VOLTAGE-DEPENDENT CALCIUM CHANNELS.
A protein of the annexin family that catalyzes the conversion of 1-D-inositol 1,2-cyclic phosphate and water to 1-D-myo-inositol 1-phosphate.
Family of calcium- and phospholipid-binding proteins which are structurally related and exhibit immunological cross-reactivity. Each member contains four homologous 70-kDa repeats. The annexins are differentially distributed in vertebrate tissues (and lower eukaryotes) and appear to be involved in MEMBRANE FUSION and SIGNAL TRANSDUCTION.
A family of highly acidic calcium-binding proteins found in large concentration in the brain and believed to be glial in origin. They are also found in other organs in the body. They have in common the EF-hand motif (EF HAND MOTIFS) found on a number of calcium binding proteins. The name of this family derives from the property of being soluble in a 100% saturated ammonium sulfate solution.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a serine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and serine and 2 moles of fatty acids.
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.
Quaternary ammonium analog of ethidium; an intercalating dye with a specific affinity to certain forms of DNA and, used as diiodide, to separate them in density gradients; also forms fluorescent complexes with cholinesterase which it inhibits.
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.
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
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.
A cell line derived from cultured tumor cells.
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.
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.
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.
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 vesicles generated by the shedding of CELL MEMBRANE blebs.
A family of G-protein-coupled receptors that was originally identified by its ability to bind N-formyl peptides such as N-FORMYLMETHIONINE LEUCYL-PHENYLALANINE. Since N-formyl peptides are found in MITOCHONDRIA and BACTERIA, this class of receptors is believed to play a role in mediating cellular responses to cellular damage and bacterial invasion. However, non-formylated peptide ligands have also been found for this receptor class.
Proteins prepared by recombinant DNA technology.
A short pro-domain caspase that plays an effector role in APOPTOSIS. It is activated by INITIATOR CASPASES such as CASPASE 9. Isoforms of this protein exist due to multiple alternative splicing of its MESSENGER RNA.
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.
Organic compounds that contain technetium as an integral part of the molecule. These compounds are often used as radionuclide imaging agents.
The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.
Established cell cultures that have the potential to propagate indefinitely.
A family of intracellular CYSTEINE ENDOPEPTIDASES that play a role in regulating INFLAMMATION and APOPTOSIS. They specifically cleave peptides at a CYSTEINE amino acid that follows an ASPARTIC ACID residue. Caspases are activated by proteolytic cleavage of a precursor form to yield large and small subunits that form the enzyme. Since the cleavage site within precursors matches the specificity of caspases, sequential activation of precursors by activated caspases can occur.
Fluorescent probe capable of being conjugated to tissue and proteins. It is used as a label in fluorescent antibody staining procedures as well as protein- and amino acid-binding techniques.
An in situ method for detecting areas of DNA which are nicked during APOPTOSIS. Terminal deoxynucleotidyl transferase is used to add labeled dUTP, in a template-independent manner, to the 3 prime OH ends of either single- or double-stranded DNA. The terminal deoxynucleotidyl transferase nick end labeling, or TUNEL, assay labels apoptosis on a single-cell level, making it more sensitive than agarose gel electrophoresis for analysis of DNA FRAGMENTATION.
A product of the lysis of plasminogen (profibrinolysin) by PLASMINOGEN activators. It is composed of two polypeptide chains, light (B) and heavy (A), with a molecular weight of 75,000. It is the major proteolytic enzyme involved in blood clot retraction or the lysis of fibrin and quickly inactivated by antiplasmins.
The parts of a macromolecule that directly participate in its specific combination with another molecule.

The Npc1 mutation causes an altered expression of caveolin-1, annexin II and protein kinases and phosphorylation of caveolin-1 and annexin II in murine livers. (1/431)

We have previously demonstrated (1) an increased expression of caveolin-1 in murine heterozygous and homozygous Niemann-Pick type C (NPC) livers, and (2) an increased concentration of unesterified cholesterol in a detergent insoluble caveolae-enriched fraction from homozygous livers. To define further the relationship between caveolin-1 function and the cholesterol trafficking defect in NPC, we examined the expression and distribution of additional caveolar and signal transduction proteins. The expression of annexin II was significantly increased in homozygous liver homogenates and the Triton X-100 insoluble floating fraction (TIFF). Phosphoamino acid analysis of caveolin-1 and annexin II from the homozygous TIFF demonstrated an increase in serine and tyrosine phosphorylation, respectively. To determine the basis for increased phosphorylation of these proteins, the expression and distribution of several protein kinases was examined. The expression of PKCalpha, PKCzeta and pp60-src (protein kinases) were significantly increased in both heterozygous and homozygous liver homogenates, while PKCdelta was increased only in homozygous livers. Of the protein kinases analyzed, only CK IIalpha was significantly enriched in the heterozygous TIFF. Finally, the concentration of diacylglycerol in the homozygous TIFF was significantly increased and this elevation may modulate PKC distribution and function. These results provide additional evidence for involvement of a caveolin-1 containing cellular fraction in the pathophysiology of NPC and also suggest that the Npc1 gene product may directly or indirectly, regulate the expression and distribution of signaling molecules.  (+info)

Tissue plasminogen activator and its receptor in the human amnion, chorion, and decidua at preterm and term. (2/431)

The plasminogen activator system consists of two proteins: tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA), which act upon their specific receptors to generate plasmin from plasminogen located on the cell surface. Plasmin then acts directly and indirectly to degrade the components of the extracellular matrix (ECM). This process is likely to be important in the normal turnover of the ECM of fetal membranes and in its premature weakening in preterm premature rupture of the fetal membranes. Quantitative Northern analysis and in situ hybridization have shown that the decidua expresses mRNA for tPA. However, the immunolocalized tPA protein was most strongly associated with the amnion and chorion, as was its receptor annexin II, suggesting that the amnion and chorion are the targets for decidual tPA. At term, decidual tPA expression was unaffected by labor, and the tPA receptor was elevated both before and after labor. At preterm, the converse was found: decidual tPA expression was significantly (p < 0. 05) up-regulated by labor, but the tPA receptor was not. The results suggest that the generation of plasmin at term would be controlled by an increased concentration of the tPA receptor in the amnion and chorion, whereas at preterm a pathological increase in plasmin would be generated by an overexpression of tPA, initiated by labor.  (+info)

Annexin II and bleeding in acute promyelocytic leukemia. (3/431)

BACKGROUND: Acute promyelocytic leukemia (APL) is associated with a hemorrhagic disorder of unknown cause that responds to treatment with all-trans-retinoic acid. METHODS: We studied a newly described receptor for fibrinolytic proteins, annexin II, in cells from patients with APL or other leukemias. We examined initial rates of in vitro generation of plasmin by tissue plasminogen activator (t-PA) in the presence of APL cells that did or did not have the characteristic translocation of APL, t(15;17). We also determined the effect of all-trans-retinoic acid on the expression of annexin II and the generation of cell-surface plasmin. RESULTS: The expression of annexin II, as detected by a fluorescein-tagged antibody, was greater on leukemic cells from patients with APL than on other types of leukemic cells (mean fluorescence intensity, 6.9 and 2.9, respectively; P<0.01). The t(15;17)-positive APL cells stimulated the generation of cell-surface, t-PA-dependent plasmin twice as efficiently as the t(15;17)-negative cells. This increase in plasmin was blocked by an anti-annexin II antibody and was induced by transfection of t(15;17)-negative cells with annexin II complementary DNA. The t(15;17)-positive APL cells contained abundant messenger RNA for annexin II, which disappeared through a transcriptional mechanism after treatment with all-trans-retinoic acid. CONCLUSIONS: Abnormally high levels of expression of annexin II on APL cells increase the production of plasmin, a fibrinolytic protein. Overexpression of annexin II may be a mechanism for the hemorrhagic complications of APL.  (+info)

Localization and quantitation of cardiac annexins II, V, and VI in hypertensive guinea pigs. (4/431)

Annexins are characterized by Ca2+-dependent binding to phospholipids. Annexin II mainly participates in cell-cell adhesion and signal transduction, whereas annexins V and VI also seem to regulate intracellular calcium cycling. Their abundance and localization were determined in left ventricle (LV) and right ventricle (RV) from hypertensive guinea pigs, during the transition from compensatory hypertrophy to heart failure. Immunoblot analysis of annexins II, V, and VI revealed an increased accumulation (2.6-, 1.45-, and 2.3-fold, respectively) in LV from hypertensive guinea pigs and no modification in RV. Immunofluorescent labeling of annexins II, V, and VI; of Na+-K+-ATPase; and of sarcomeric alpha-actinin showed that in control LV and RV, 1) annexin II is present in nonmuscle cells; 2) annexins V and VI are mainly observed in the sarcolemma and intercalated disks of myocytes; 3) annexins II, V, and VI strongly label endothelial cells and adventitia of coronary arteries; and 4) annexin VI is present in the media. At the onset of heart failure, the most striking changes are the increased protein accumulation in LV and the very strong labeling of annexins II, V, and VI in interstitial tissue, suggesting a role in fibrosis development and cardiac remodeling.  (+info)

The biological effects induced in mice by p36, a proteinaceous factor of virulence produced by African swine fever virus, are mediated by interleukin-4 and also to a lesser extent by interleukin-10. (5/431)

We have previously presented indirect evidence that both specific immunosuppression and lymphocyte mitogenicity induced in mice by p36, a proteinaceous factor of virulence produced by porcine monocytes infected by African swine fever virus, were consistent with a Th2-driven response. Here we show: (1) Interleukin-4 (IL-4) and interleukin-10 (IL-10) mRNA expression in the spleen and thymus of C57BL/6 mice were displayed early after p36 inoculation. The expression of thymic IL-10 mRNA occurred, however, later than that of IL-4 mRNA. (2) Increased serum levels of these two cytokines were also soon detected after the protein inoculation. (3) Both immunosuppressive and mitogenic effects of p36 were absent in IL-4 gene-targeted mice and partially abrogated in mice depleted of IL-4 by neutralizing monoclonal antibodies. (4) IL-10 depletion abrogated the immunosuppressive but not the p36 lymphocyte mitogenic biological effects. (5) The increase in the serum concentrations of both IL-4 and IL-10 were lower in thymectomized than in non-thymectomized mice. (6) The expression of interferon-gamma (IFN-gamma) mRNA was weakly or not at all induced in p36-treated mice. Taken together, these results are in agreement with the promotion of a Th2 immune response induced by p36.  (+info)

Dexamethasone alters arachidonate release from human epithelial cells by induction of p11 protein synthesis and inhibition of phospholipase A2 activity. (6/431)

The effect of the glucocorticosteroid, dexamethasone, on arachidonic acid (AA) release and on protein levels of p11 and cytosolic phospholipase A2 (cPLA2) was studied in two epithelial cell lines, HeLa cells and BEAS-2B cells. Dexamethasone treatment of HeLa cells and BEAS-2B cells increased cellular p11 protein and mRNA levels in a time- and dose-dependent manner. It had little effect on levels of cPLA2 protein. In order to determine if increased p11 protein expression resulted in increased interaction between p11 and cPLA2, anti-cPLA2 antibodies were used to immunoprecipitate p11.cPLA2 complexes and Western blots of the immunoprecipitate were used to detect p11. In cells treated with dexamethasone, more p11 was detected in the anti-cPLA2 immunoprecipitate compared with control cells. Dexamethasone treatment of HeLa cells prelabeled with [3H]AA decreased the release of [3H]AA under basal conditions and after stimulation with the calcium ionophore A23187 (10(-6) M). In order to determine if altering the p11 protein levels in HeLa cells independent of glucocorticosteroid treatment could also produce an effect on [3H]AA release, cells were stably transfected with plasmids expressing either p11 antisense mRNA or p11 mRNA. Cloned HeLa cells expressing p11 antisense mRNA exhibited less cellular p11 protein compared with control cells and greater [3H]AA release compared with cells transfected with a control vector. Cloned HeLa cells stably transfected with a p11 expression vector exhibited increased p11 cellular protein and diminished [3H]AA release under basal conditions and in response to A23187. Therefore, dexamethasone alteration of epithelial cell AA release may be due in part to induction of p11 protein expression.  (+info)

Annexin II increases osteoclast formation by stimulating the proliferation of osteoclast precursors in human marrow cultures. (7/431)

Annexin II (AXII), a calcium-dependent phospholipid-binding protein, has been recently found to be an osteoclast (OCL) stimulatory factor that is also secreted by OCLs. In vitro studies showed that AXII induced OCL formation and bone resorption. However, the mechanism of action by which AXII acts as a soluble extracellular protein to induce OCL formation is unknown. In this paper, we demonstrate that AXII gene expression is upregulated by 1,25-dihydroxyvitamin D3 [1, 25-(OH)2D3] and that addition of AXII significantly increased OCL-like multinucleated cell formation. Time-course studies suggested that AXII acted on the proliferative stage of OCL precursors and that AXII increased thymidine incorporation in OCL precursors. Moreover, AXII enhanced the growth of CFU-GM, the earliest identifiable OCL precursor, when bone marrow cultures were treated with low concentrations of GM-CSF. This capacity of AXII to induce OCL precursor proliferation was due to induction of GM-CSF expression, because the addition of neutralizing antibodies to GM-CSF blocked the stimulatory effect of AXII on OCL formation. RT-PCR analysis using RNA from highly purified subpopulations of marrow cells demonstrated that T cells, especially CD4(+) T cells, produced GM-CSF in response to AXII. Furthermore, FACS(R) analysis of T-cell subpopulations treated with fluorescein-labeled AXII suggested that the CD4(+), but not CD8(+), subpopulation of T cells express an AXII receptor. Taken together, these data suggest that AXII stimulates OCL formation by activating T cells through a putative receptor to secrete GM-CSF. GM-CSF then expands the OCL precursor pool to enhance OCL formation.  (+info)

Interference with annexin II has no effect on entry of human cytomegalovirus into fibroblast cells. (8/431)

Annexin II has been identified as a human cytomegalovirus (HCMV)-binding protein, shown to be a component of purified virions and proposed as a cellular receptor for the virus. In addition, annexin II is capable of associating with the major HCMV envelope glycoprotein, gB (gpUL55). As one approach to examine the role of annexin II in virus entry, a high-titre polyclonal annexin II-specific antibody was produced and its effects in virus entry and cell-to-cell spread assays were tested. This anti-annexin II serum recognized virion and cell surface annexin II and annexin II-derived peptides. Recombinant annexin II, with characteristic calcium- and phospholipid-binding activities, was also examined. Pretreatment of cells, virions or both with polyclonal anti-annexin II serum, affinity-purified anti-annexin II antibodies or recombinant annexin II protein prior to infection was inconsequential to the entry of HCMV into fibroblasts. HCMV was also able to dose-dependently penetrate annexin II-deficient 293 cells. Furthermore, the spread of HCMV from cell to cell was not inhibited in the presence of polyclonal anti-annexin II antibodies or exogenous annexin II protein. These experiments do not support a direct role of annexin II in virus entry or spread. Alternative roles for the gB-annexin II interaction are proposed.  (+info)

Annexin A2 is a protein found in various types of cells, including those that line the inside of blood vessels. It is a member of the annexin family of proteins, which are characterized by their ability to bind to calcium ions and membranes. Annexin A2 is involved in several cellular processes, including the regulation of ion channels, the modulation of enzyme activity, and the promotion of cell adhesion and migration. It also plays a role in the coagulation of blood, and has been implicated in the development and progression of various diseases, including cancer and cardiovascular disease.

Annexin A1 is a protein that belongs to the annexin family, which are calcium-dependent phospholipid-binding proteins. This protein is found in various tissues, including the human body, and has multiple functions, such as anti-inflammatory, anti-proliferative, and pro-resolving activities. It plays a crucial role in regulating cellular processes like apoptosis (programmed cell death), membrane organization, and signal transduction.

Annexin A1 is also known to interact with other proteins and receptors, such as the formyl peptide receptor 2 (FPR2), which contributes to its immunomodulatory functions. In addition, it has been implicated in several pathophysiological conditions, including cancer, inflammation, and autoimmune diseases.

Modulating Annexin A1 levels or activity may provide therapeutic benefits for various medical conditions; however, further research is required to fully understand its potential as a drug target.

Annexin A5 is a protein that belongs to the annexin family, which are calcium-dependent phospholipid-binding proteins. Annexin A5 has high affinity for phosphatidylserine, a type of phospholipid that is usually located on the inner leaflet of the plasma membrane in healthy cells. However, when cells undergo apoptosis (programmed cell death), phosphatidylserine is exposed on the outer leaflet of the plasma membrane.

Annexin A5 can bind to exposed phosphatidylserine on the surface of apoptotic cells and is commonly used as a marker for detecting apoptosis in various experimental settings, including flow cytometry, immunohistochemistry, and imaging techniques. Annexin A5-based assays are widely used in research and clinical settings to study the mechanisms of apoptosis and to develop diagnostic tools for various diseases, such as cancer, neurodegenerative disorders, and cardiovascular diseases.

Annexin A6 is a protein that belongs to the annexin family, which are calcium-dependent phospholipid-binding proteins. Annexin A6 is involved in various cellular processes such as exocytosis, endocytosis, and membrane trafficking. It has been shown to play a role in regulating ion channels, modulating the actin cytoskeleton, and interacting with other proteins to form multimolecular complexes. Annexin A6 is expressed in various tissues, including the heart, lung, kidney, and pancreas. Mutations in the ANXA6 gene have been associated with certain diseases, such as kidney stones and cataracts.

Annexin A4 is a type of protein that belongs to the annexin family, which are characterized by their ability to bind to calcium ions and membranes. Specifically, Annexin A4 is known to play roles in various cellular processes such as exocytosis, endocytosis, and regulation of ion channels. It has also been implicated in the development and progression of certain diseases, including cancer and neurological disorders.

In the medical field, the study of Annexin A4 is important for understanding its functions and potential therapeutic applications. For example, research has suggested that targeting Annexin A4 may be a useful strategy for developing new treatments for cancer or other diseases. However, more studies are needed to fully elucidate the role of this protein in various biological processes and disease states.

Annexin A7 is a type of protein that belongs to the annexin family, which are characterized by their ability to bind to cell membranes in a calcium-dependent manner. Specifically, Annexin A7 (also known as Syntaxin-binding protein 1 or SBP1) is involved in various cellular processes such as exocytosis, endocytosis, and signal transduction. It has been shown to interact with other proteins, including syntaxins, which are important for vesicle trafficking and fusion. Additionally, Annexin A7 may have a role in regulating apoptosis (programmed cell death) and has been implicated in several diseases, including cancer and neurodegenerative disorders. However, more research is needed to fully understand the functions and regulatory mechanisms of this protein.

Annexin A3 is a type of protein that belongs to the annexin family, which are characterized by their ability to bind to calcium ions and membranes. Specifically, annexin A3 is involved in various cellular processes such as exocytosis, endocytosis, and signal transduction. It has been found to play a role in the regulation of blood clotting, inflammation, and cancer metastasis. Annexin A3 can be found on the surface of various cells, including platelets, neutrophils, and tumor cells. In addition, annexin A3 has been identified as a potential biomarker for certain types of cancer, such as ovarian and prostate cancer.

Annexins are a family of calcium-dependent phospholipid-binding proteins that are found in various organisms, including humans. They are involved in several cellular processes, such as membrane organization, signal transduction, and regulation of ion channels. Some annexins also have roles in inflammation, blood coagulation, and apoptosis (programmed cell death).

Annexins have a conserved structure, consisting of a core domain that binds to calcium ions and a variable number of domains that bind to phospholipids. This allows annexins to interact with membranes in a calcium-dependent manner, which is important for their functions.

There are several different annexin proteins, each with its own specific functions and expression patterns. For example, annexin A1 is involved in the regulation of inflammation and has been studied as a potential target for anti-inflammatory therapies. Annexin A2 is involved in the regulation of coagulation and has been studied as a potential target for anticoagulant therapies. Other annexins have roles in cell division, differentiation, and survival.

Overall, annexins are important regulators of various cellular processes and have potential as targets for therapeutic intervention in a variety of diseases.

S100 proteins are a family of calcium-binding proteins that are involved in the regulation of various cellular processes, including cell growth and differentiation, intracellular signaling, and inflammation. They are found in high concentrations in certain types of cells, such as nerve cells (neurons), glial cells (supporting cells in the nervous system), and skin cells (keratinocytes).

The S100 protein family consists of more than 20 members, which are divided into several subfamilies based on their structural similarities. Some of the well-known members of this family include S100A1, S100B, S100 calcium-binding protein A8 (S100A8), and S100 calcium-binding protein A9 (S100A9).

Abnormal expression or regulation of S100 proteins has been implicated in various pathological conditions, such as neurodegenerative diseases, cancer, and inflammatory disorders. For example, increased levels of S100B have been found in the brains of patients with Alzheimer's disease, while overexpression of S100A8 and S100A9 has been associated with the development and progression of certain types of cancer.

Therefore, understanding the functions and regulation of S100 proteins is important for developing new diagnostic and therapeutic strategies for various diseases.

Phosphatidylserines are a type of phospholipids that are essential components of the cell membrane, particularly in the brain. They play a crucial role in maintaining the fluidity and permeability of the cell membrane, and are involved in various cellular processes such as signal transduction, protein anchorage, and apoptosis (programmed cell death). Phosphatidylserines contain a polar head group made up of serine amino acids and two non-polar fatty acid tails. They are abundant in the inner layer of the cell membrane but can be externalized to the outer layer during apoptosis, where they serve as signals for recognition and removal of dying cells by the immune system. Phosphatidylserines have been studied for their potential benefits in various medical conditions, including cognitive decline, Alzheimer's disease, and depression.

Apoptosis is a programmed and controlled cell death process that occurs in multicellular organisms. It is a natural process that helps maintain tissue homeostasis by eliminating damaged, infected, or unwanted cells. During apoptosis, the cell undergoes a series of morphological changes, including cell shrinkage, chromatin condensation, and fragmentation into membrane-bound vesicles called apoptotic bodies. These bodies are then recognized and engulfed by neighboring cells or phagocytic cells, preventing an inflammatory response. Apoptosis is regulated by a complex network of intracellular signaling pathways that involve proteins such as caspases, Bcl-2 family members, and inhibitors of apoptosis (IAPs).

Propidium is not a medical condition or diagnosis, but rather it is a fluorescent dye that is used in medical and scientific research. It is often used in procedures such as flow cytometry and microscopy to stain and label cells or nucleic acids (DNA or RNA). Propidium iodide is the most commonly used form of propidium, which binds to DNA by intercalating between the bases.

Once stained with propidium iodide, cells with damaged membranes will take up the dye and can be detected and analyzed based on their fluorescence intensity. This makes it possible to identify and quantify dead or damaged cells in a population, as well as to analyze DNA content and cell cycle status.

Overall, propidium is an important tool in medical research and diagnostics, providing valuable information about cell health, viability, and genetic material.

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.

Phospholipids are a major class of lipids that consist of a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails. The head is composed of a phosphate group, which is often bound to an organic molecule such as choline, ethanolamine, serine or inositol. The tails are made up of two fatty acid chains.

Phospholipids are a key component of cell membranes and play a crucial role in maintaining the structural integrity and function of the cell. They form a lipid bilayer, with the hydrophilic heads facing outwards and the hydrophobic tails facing inwards, creating a barrier that separates the interior of the cell from the outside environment.

Phospholipids are also involved in various cellular processes such as signal transduction, intracellular trafficking, and protein function regulation. Additionally, they serve as emulsifiers in the digestive system, helping to break down fats in the diet.

Calcium-binding proteins (CaBPs) are a diverse group of proteins that have the ability to bind calcium ions (Ca^2+^) with high affinity and specificity. They play crucial roles in various cellular processes, including signal transduction, muscle contraction, neurotransmitter release, and protection against oxidative stress.

The binding of calcium ions to these proteins induces conformational changes that can either activate or inhibit their functions. Some well-known CaBPs include calmodulin, troponin C, S100 proteins, and parvalbumins. These proteins are essential for maintaining calcium homeostasis within cells and for mediating the effects of calcium as a second messenger in various cellular signaling pathways.

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.

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.

A cell line that is derived from tumor cells and has been adapted to grow in culture. These cell lines are often used in research to study the characteristics of cancer cells, including their growth patterns, genetic changes, and responses to various treatments. They can be established from many different types of tumors, such as carcinomas, sarcomas, and leukemias. Once established, these cell lines can be grown and maintained indefinitely in the laboratory, allowing researchers to conduct experiments and studies that would not be feasible using primary tumor cells. It is important to note that tumor cell lines may not always accurately represent the behavior of the original tumor, as they can undergo genetic changes during their time in culture.

"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.

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.

Flow cytometry is a medical and research technique used to measure physical and chemical characteristics of cells or particles, one cell at a time, as they flow in a fluid stream through a beam of light. The properties measured include:

* Cell size (light scatter)
* Cell internal complexity (granularity, also light scatter)
* Presence or absence of specific proteins or other molecules on the cell surface or inside the cell (using fluorescent antibodies or other fluorescent probes)

The technique is widely used in cell counting, cell sorting, protein engineering, biomarker discovery and monitoring disease progression, particularly in hematology, immunology, and cancer research.

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.

Cell-derived microparticles (CDMs), also known as microvesicles or microparticles, are small membrane-bound particles that are released from the cell surface upon activation or apoptosis of various cell types, including platelets, leukocytes, endothelial cells, and red blood cells. CDMs range in size from 0.1 to 1.0 micrometers in diameter and contain a variety of bioactive molecules, such as lipids, proteins, and nucleic acids, which can be transferred to neighboring or distant cells, thereby modulating their function.

CDMs have been implicated in various physiological and pathological processes, including coagulation, inflammation, immune response, angiogenesis, and cancer progression. They have also emerged as potential biomarkers for various diseases, such as cardiovascular disease, sepsis, and cancer, due to their distinct molecular signature and abundance in body fluids, such as blood, urine, and cerebrospinal fluid.

The mechanisms of CDM formation and release are complex and involve several cellular processes, including cytoskeletal rearrangement, membrane budding, and vesicle shedding. The molecular composition of CDMs reflects their cellular origin and activation state, and can be analyzed by various techniques, such as flow cytometry, proteomics, and transcriptomics, to gain insights into their biological functions and clinical relevance.

Formyl peptide receptors (FPRs) are a type of G protein-coupled receptors that play a crucial role in the innate immune system. They are expressed on various cells including neutrophils, monocytes, and macrophages. FPRs recognize and respond to formylated peptides derived from bacteria, mitochondria, and host proteins during cell damage or stress. Activation of FPRs triggers a variety of cellular responses, such as chemotaxis, phagocytosis, and release of inflammatory mediators, which help to eliminate invading pathogens and promote tissue repair. There are three subtypes of human FPRs (FPR1, FPR2, and FPR3) that have distinct ligand specificities and functions in the immune response.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

Caspase-3 is a type of protease enzyme that plays a central role in the execution-phase of cell apoptosis, or programmed cell death. It's also known as CPP32 (CPP for ced-3 protease precursor) or apopain. Caspase-3 is produced as an inactive protein that is activated when cleaved by other caspases during the early stages of apoptosis. Once activated, it cleaves a variety of cellular proteins, including structural proteins, enzymes, and signal transduction proteins, leading to the characteristic morphological and biochemical changes associated with apoptotic cell death. Caspase-3 is often referred to as the "death protease" because of its crucial role in executing the cell death program.

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.

Organotechnetium compounds are chemical substances that contain carbon-technetium bonds, where technetium is an element with the symbol Tc and atomic number 43. These types of compounds are primarily used in medical imaging as radioactive tracers due to the ability of technetium-99m to emit gamma rays. The organotechnetium compounds help in localizing specific organs, tissues, or functions within the body, making them useful for diagnostic purposes in nuclear medicine.

It is important to note that most organotechnetium compounds are synthesized from technetium-99m, which is generated from the decay of molybdenum-99. The use of these compounds requires proper handling and administration by trained medical professionals due to their radioactive nature.

Cell survival refers to the ability of a cell to continue living and functioning normally, despite being exposed to potentially harmful conditions or treatments. This can include exposure to toxins, radiation, chemotherapeutic drugs, or other stressors that can damage cells or interfere with their normal processes.

In scientific research, measures of cell survival are often used to evaluate the effectiveness of various therapies or treatments. For example, researchers may expose cells to a particular drug or treatment and then measure the percentage of cells that survive to assess its potential therapeutic value. Similarly, in toxicology studies, measures of cell survival can help to determine the safety of various chemicals or substances.

It's important to note that cell survival is not the same as cell proliferation, which refers to the ability of cells to divide and multiply. While some treatments may promote cell survival, they may also inhibit cell proliferation, making them useful for treating diseases such as cancer. Conversely, other treatments may be designed to specifically target and kill cancer cells, even if it means sacrificing some healthy cells in the process.

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.

Caspases are a family of protease enzymes that play essential roles in programmed cell death, also known as apoptosis. These enzymes are produced as inactive precursors and are activated when cells receive signals to undergo apoptosis. Once activated, caspases cleave specific protein substrates, leading to the characteristic morphological changes and DNA fragmentation associated with apoptotic cell death. Caspases also play roles in other cellular processes, including inflammation and differentiation. There are two types of caspases: initiator caspases (caspase-2, -8, -9, and -10) and effector caspases (caspase-3, -6, and -7). Initiator caspases are activated in response to various apoptotic signals and then activate the effector caspases, which carry out the proteolytic cleavage of cellular proteins. Dysregulation of caspase activity has been implicated in a variety of diseases, including neurodegenerative disorders, ischemic injury, and cancer.

Fluorescein-5-isothiocyanate (FITC) is not a medical term per se, but a chemical compound commonly used in biomedical research and clinical diagnostics. Therefore, I will provide a general definition of this term:

Fluorescein-5-isothiocyanate (FITC) is a fluorescent dye with an absorption maximum at approximately 492-495 nm and an emission maximum at around 518-525 nm. It is widely used as a labeling reagent for various biological molecules, such as antibodies, proteins, and nucleic acids, to study their structure, function, and interactions in techniques like flow cytometry, immunofluorescence microscopy, and western blotting. The isothiocyanate group (-N=C=S) in the FITC molecule reacts with primary amines (-NH2) present in biological molecules to form a stable thiourea bond, enabling specific labeling of target molecules for detection and analysis.

In situ nick-end labeling (ISEL, also known as TUNEL) is a technique used in pathology and molecular biology to detect DNA fragmentation, which is a characteristic of apoptotic cells (cells undergoing programmed cell death). The method involves labeling the 3'-hydroxyl termini of double or single stranded DNA breaks in situ (within tissue sections or individual cells) using modified nucleotides that are coupled to a detectable marker, such as a fluorophore or an enzyme. This technique allows for the direct visualization and quantification of apoptotic cells within complex tissues or cell populations.

Fibrinolysin is defined as a proteolytic enzyme that dissolves or breaks down fibrin, a protein involved in the clotting of blood. This enzyme is produced by certain cells, such as endothelial cells that line the interior surface of blood vessels, and is an important component of the body's natural mechanism for preventing excessive blood clotting and maintaining blood flow.

Fibrinolysin works by cleaving specific bonds in the fibrin molecule, converting it into soluble degradation products that can be safely removed from the body. This process is known as fibrinolysis, and it helps to maintain the balance between clotting and bleeding in the body.

In medical contexts, fibrinolysin may be used as a therapeutic agent to dissolve blood clots that have formed in the blood vessels, such as those that can occur in deep vein thrombosis or pulmonary embolism. It is often administered in combination with other medications that help to enhance its activity and specificity for fibrin.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

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