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.Protein Tyrosine Phosphatases: An enzyme group that specifically dephosphorylates phosphotyrosyl residues in selected proteins. Together with PROTEIN-TYROSINE KINASE, it regulates tyrosine phosphorylation and dephosphorylation in cellular signal transduction and may play a role in cell growth control and carcinogenesis.Tyrosine: A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.src Homology Domains: Regions of AMINO ACID SEQUENCE similarity in the SRC-FAMILY TYROSINE KINASES that fold into specific functional tertiary structures. The SH1 domain is a CATALYTIC DOMAIN. SH2 and SH3 domains are protein interaction domains. SH2 usually binds PHOSPHOTYROSINE-containing proteins and SH3 interacts with CYTOSKELETAL PROTEINS.Protein-Tyrosine Kinases: Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.Vanadates: Oxyvanadium ions in various states of oxidation. They act primarily as ion transport inhibitors due to their inhibition of Na(+)-, K(+)-, and Ca(+)-ATPase transport systems. They also have insulin-like action, positive inotropic action on cardiac ventricular muscle, and other metabolic effects.PhosphopeptidesPhosphoproteinsShc Signaling Adaptor Proteins: A family of signaling adaptor proteins that contain SRC HOMOLOGY DOMAINS. Many members of this family are involved in transmitting signals from CELL SURFACE RECEPTORS to MITOGEN-ACTIVATED PROTEIN KINASES.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.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.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.Adaptor Proteins, Signal Transducing: A broad category of carrier proteins that play a role in SIGNAL TRANSDUCTION. They generally contain several modular domains, each of which having its own binding activity, and act by forming complexes with other intracellular-signaling molecules. Signal-transducing adaptor proteins lack enzyme activity, however their activity can be modulated by other signal-transducing enzymesProtein Tyrosine Phosphatase, Non-Receptor Type 6: A Src-homology domain-containing protein tyrosine phosphatase found in the CYTOSOL of hematopoietic cells. It plays a role in signal transduction by dephosphorylating signaling proteins that are activated or inactivated by PROTEIN-TYROSINE KINASES.Protein Tyrosine Phosphatase, Non-Receptor Type 11: A subtype of non-receptor protein tyrosine phosphatases that contain two SRC HOMOLOGY DOMAINS. Mutations in the gene for protein tyrosine phosphatase, non-receptor type 11 are associated with NOONAN SYNDROME.Oncogene Protein pp60(v-src): A tyrosine-specific protein kinase encoded by the v-src oncogene of ROUS SARCOMA VIRUS. The transforming activity of pp60(v-src) depends on both the lack of a critical carboxy-terminal tyrosine phosphorylation site at position 527, and the attachment of pp60(v-src) to the plasma membrane which is accomplished by myristylation of its N-terminal glycine.GRB2 Adaptor Protein: A signal transducing adaptor protein that links extracellular signals to the MAP KINASE SIGNALING SYSTEM. Grb2 associates with activated EPIDERMAL GROWTH FACTOR RECEPTOR and PLATELET-DERIVED GROWTH FACTOR RECEPTORS via its SH2 DOMAIN. It also binds to and translocates the SON OF SEVENLESS PROTEINS through its SH3 DOMAINS to activate PROTO-ONCOGENE PROTEIN P21(RAS).Cell Line: Established cell cultures that have the potential to propagate indefinitely.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Proto-Oncogene Proteins pp60(c-src): Membrane-associated tyrosine-specific kinases encoded by the c-src genes. They have an important role in cellular growth control. Truncation of carboxy-terminal residues in pp60(c-src) leads to PP60(V-SRC) which has the ability to transform cells. This kinase pp60 c-src should not be confused with csk, also known as c-src kinase.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.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.Receptor, Insulin: A cell surface receptor for INSULIN. It comprises a tetramer of two alpha and two beta subunits which are derived from cleavage of a single precursor protein. The receptor contains an intrinsic TYROSINE KINASE domain that is located within the beta subunit. Activation of the receptor by INSULIN results in numerous metabolic changes including increased uptake of GLUCOSE into the liver, muscle, and ADIPOSE TISSUE.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Phosphoserine: The phosphoric acid ester of serine.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.SH2 Domain-Containing Protein Tyrosine Phosphatases: A subcategory of protein tyrosine phosphatases that contain SH2 type SRC HOMOLOGY DOMAINS. Many of the proteins in this class are recruited to specific cellular targets such as a cell surface receptor complexes via their SH2 domain.Intracellular Signaling Peptides and Proteins: Proteins and peptides that are involved in SIGNAL TRANSDUCTION within the cell. Included here are peptides and proteins that regulate the activity of TRANSCRIPTION FACTORS and cellular processes in response to signals from CELL SURFACE RECEPTORS. Intracellular signaling peptide and proteins may be part of an enzymatic signaling cascade or act through binding to and modifying the action of other signaling factors.Protein Tyrosine Phosphatase, Non-Receptor Type 1: A subtype of non-receptor protein tyrosine phosphatases that includes two distinctive targeting motifs; an N-terminal motif specific for the INSULIN RECEPTOR, and a C-terminal motif specific for the SH3 domain containing proteins. This subtype includes a hydrophobic domain which localizes it to the ENDOPLASMIC RETICULUM.Adaptor Proteins, Vesicular Transport: A class of proteins involved in the transport of molecules via TRANSPORT VESICLES. They perform functions such as binding to the cell membrane, capturing cargo molecules and promoting the assembly of CLATHRIN. The majority of adaptor proteins exist as multi-subunit complexes, however monomeric varieties have also been found.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.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Receptor, Epidermal Growth Factor: A cell surface receptor involved in regulation of cell growth and differentiation. It is specific for EPIDERMAL GROWTH FACTOR and EGF-related peptides including TRANSFORMING GROWTH FACTOR ALPHA; AMPHIREGULIN; and HEPARIN-BINDING EGF-LIKE GROWTH FACTOR. The binding of ligand to the receptor causes activation of its intrinsic tyrosine kinase activity and rapid internalization of the receptor-ligand complex into the cell.Receptors, Platelet-Derived Growth Factor: Specific receptors on cell membranes that react with PLATELET-DERIVED GROWTH FACTOR, its analogs, or antagonists. The alpha PDGF receptor (RECEPTOR, PLATELET-DERIVED GROWTH FACTOR ALPHA) and the beta PDGF receptor (RECEPTOR, PLATELET-DERIVED GROWTH FACTOR BETA) are the two principle types of PDGF receptors. Activation of the protein-tyrosine kinase activity of the receptors occurs by ligand-induced dimerization or heterodimerization of PDGF receptor types.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.Molecular Weight: The sum of the weight of all the atoms in a molecule.Proto-Oncogene Proteins: Products of proto-oncogenes. Normally they do not have oncogenic or transforming properties, but are involved in the regulation or differentiation of cell growth. They often have protein kinase activity.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Phosphoprotein Phosphatases: A group of enzymes removing the SERINE- or THREONINE-bound phosphate groups from a wide range of phosphoproteins, including a number of enzymes which have been phosphorylated under the action of a kinase. (Enzyme Nomenclature, 1992)Kinetics: The rate dynamics in chemical or physical systems.Focal Adhesion Protein-Tyrosine Kinases: A family of non-receptor, PROLINE-rich protein-tyrosine kinases.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.Receptor Protein-Tyrosine Kinases: A class of cellular receptors that have an intrinsic PROTEIN-TYROSINE KINASE activity.Insulin Receptor Substrate Proteins: A structurally-related group of signaling proteins that are phosphorylated by the INSULIN RECEPTOR PROTEIN-TYROSINE KINASE. The proteins share in common an N-terminal PHOSPHOLIPID-binding domain, a phosphotyrosine-binding domain that interacts with the phosphorylated INSULIN RECEPTOR, and a C-terminal TYROSINE-rich domain. Upon tyrosine phosphorylation insulin receptor substrate proteins interact with specific SH2 DOMAIN-containing proteins that are involved in insulin receptor signaling.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.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.Protein Kinases: A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.Genes, src: Retrovirus-associated DNA sequences (src) originally isolated from the Rous sarcoma virus (RSV). The proto-oncogene src (c-src) codes for a protein that is a member of the tyrosine kinase family and was the first proto-oncogene identified in the human genome. The human c-src gene is located at 20q12-13 on the long arm of chromosome 20.Epidermal Growth Factor: A 6-kDa polypeptide growth factor initially discovered in mouse submaxillary glands. Human epidermal growth factor was originally isolated from urine based on its ability to inhibit gastric secretion and called urogastrone. Epidermal growth factor exerts a wide variety of biological effects including the promotion of proliferation and differentiation of mesenchymal and EPITHELIAL CELLS. It is synthesized as a transmembrane protein which can be cleaved to release a soluble active form.Recombinant Proteins: Proteins prepared by recombinant DNA technology.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.Phosphothreonine: The phosphoric acid ester of threonine. Used as an identifier in the analysis of peptides, proteins, and enzymes.Phospholipase C gamma: A phosphoinositide phospholipase C subtype that is primarily regulated by PROTEIN-TYROSINE KINASES. It is structurally related to PHOSPHOLIPASE C DELTA with the addition of SRC HOMOLOGY DOMAINS and pleckstrin homology domains located between two halves of the CATALYTIC DOMAIN.Platelet-Derived Growth Factor: Mitogenic peptide growth hormone carried in the alpha-granules of platelets. It is released when platelets adhere to traumatized tissues. Connective tissue cells near the traumatized region respond by initiating the process of replication.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.Proto-Oncogene Proteins c-fyn: Src-family kinases that associate with T-CELL ANTIGEN RECEPTOR and phosphorylate a wide variety of intracellular signaling molecules.Cells, Cultured: 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.Proto-Oncogene Proteins c-cbl: Proto-oncogene proteins that negatively regulate RECEPTOR PROTEIN-TYROSINE KINASE signaling. It is a UBIQUITIN-PROTEIN LIGASE and the cellular homologue of ONCOGENE PROTEIN V-CBL.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.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Receptor, EphA8: An eph family receptor found exclusively in BRAIN. EphA8 receptors may play a role in the axonal guidance of a subset of tectal commissural NEURONS.Vanadium: A metallic element with the atomic symbol V, atomic number 23, and atomic weight 50.94. It is used in the manufacture of vanadium steel. Prolonged exposure can lead to chronic intoxication caused by absorption usually via the lungs.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Peptide Mapping: Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.Lymphocyte Specific Protein Tyrosine Kinase p56(lck): This enzyme is a lymphoid-specific src family tyrosine kinase that is critical for T-cell development and activation. Lck is associated with the cytoplasmic domains of CD4, CD8 and the beta-chain of the IL-2 receptor, and is thought to be involved in the earliest steps of TCR-mediated T-cell activation.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Oncogene Protein v-crk: A signal transducing adaptor protein that is encoded by the crk ONCOGENE from TYPE C AVIAN RETROVIRUSES. It contains SRC HOMOLOGY DOMAINS and is closely related to its cellular homolog, PROTO-ONCOGENE PROTEIN C-CRK.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.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.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).)Protein Tyrosine Phosphatases, Non-Receptor: A subcategory of protein tyrosine phosphatases that occur in the CYTOPLASM. Many of the proteins in this category play a role in intracellular signal transduction.Sarcoma Viruses, Feline: Species of GAMMARETROVIRUS isolated from fibrosarcoma in cats. The viruses are actually recombinant feline leukemia viruses (FeLV) where part of the genome has been replaced by cellular oncogenes. It is unique to individuals and not transmitted naturally to other cats. FeSVs are replication defective and require FeLV to reproduce.NitrophenolsGlutathione Transferase: A transferase that catalyzes the addition of aliphatic, aromatic, or heterocyclic FREE RADICALS as well as EPOXIDES and arene oxides to GLUTATHIONE. Addition takes place at the SULFUR. It also catalyzes the reduction of polyol nitrate by glutathione to polyol and nitrite.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.Avian Sarcoma Viruses: Group of alpharetroviruses (ALPHARETROVIRUS) producing sarcomata and other tumors in chickens and other fowl and also in pigeons, ducks, and RATS.Phosphorus Radioisotopes: Unstable isotopes of phosphorus that decay or disintegrate emitting radiation. P atoms with atomic weights 28-34 except 31 are radioactive phosphorus isotopes.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Type C Phospholipases: A subclass of phospholipases that hydrolyze the phosphoester bond found in the third position of GLYCEROPHOSPHOLIPIDS. Although the singular term phospholipase C specifically refers to an enzyme that catalyzes the hydrolysis of PHOSPHATIDYLCHOLINE (EC, it is commonly used in the literature to refer to broad variety of enzymes that specifically catalyze the hydrolysis of PHOSPHATIDYLINOSITOLS.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Amino Acid Motifs: Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.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.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Proto-Oncogene Proteins c-abl: Non-receptor tyrosine kinases encoded by the C-ABL GENES. They are distributed in both the cytoplasm and the nucleus. c-Abl plays a role in normal HEMATOPOIESIS especially of the myeloid lineage. Oncogenic transformation of c-abl arises when specific N-terminal amino acids are deleted, releasing the kinase from negative regulation.Retroviridae Proteins, Oncogenic: Retroviral proteins that have the ability to transform cells. They can induce sarcomas, leukemias, lymphomas, and mammary carcinomas. Not all retroviral proteins are oncogenic.Cell Transformation, Viral: An inheritable change in cells manifested by changes in cell division and growth and alterations in cell surface properties. It is induced by infection with a transforming virus.Protein Tyrosine Phosphatase, Non-Receptor Type 12: A subtype of non-receptor protein tyrosine phosphatases that is characterized by the presence of a N-terminal catalytic domain and a large C-terminal domain that is enriched in PROLINE, GLUTAMIC ACID, SERINE, and THREONINE residues (PEST sequences). The phosphatase subtype is ubiquitously expressed and implicated in the regulation of a variety of biological processes such as CELL MOVEMENT; CYTOKINESIS; focal adhesion disassembly; and LYMPHOCYTE ACTIVATION.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.Receptor, trkA: A protein-tyrosine kinase receptor that is specific for NERVE GROWTH FACTOR; NEUROTROPHIN 3; neurotrophin 4, neurotrophin 5. It plays a crucial role in pain sensation and thermoregulation in humans. Gene mutations that cause loss of receptor function are associated with CONGENITAL INSENSITIVITY TO PAIN WITH ANHIDROSIS, while gene rearrangements that activate the protein-tyrosine kinase function are associated with tumorigenesis.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.Genistein: An isoflavonoid derived from soy products. It inhibits PROTEIN-TYROSINE KINASE and topoisomerase-II (DNA TOPOISOMERASES, TYPE II); activity and is used as an antineoplastic and antitumor agent. Experimentally, it has been shown to induce G2 PHASE arrest in human and murine cell lines and inhibits PROTEIN-TYROSINE KINASE.Son of Sevenless Proteins: A class of RAS GUANINE NUCLEOTIDE EXCHANGE FACTORS that are genetically related to the Son of Sevenless gene from DROSOPHILA. Sevenless refers to genetic mutations in DROSOPHILA that cause loss of the R7 photoreceptor which is required to see UV light.Anion Exchange Protein 1, Erythrocyte: A major integral transmembrane protein of the ERYTHROCYTE MEMBRANE. It is the anion exchanger responsible for electroneutral transporting in CHLORIDE IONS in exchange of BICARBONATE IONS allowing CO2 uptake and transport from tissues to lungs by the red blood cells. Genetic mutations that result in a loss of the protein function have been associated with type 4 HEREDITARY SPHEROCYTOSIS.Cell Adhesion: Adherence of cells to surfaces or to other cells.Cell Transformation, Neoplastic: Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.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.Sperm Capacitation: The structural and functional changes by which SPERMATOZOA become capable of oocyte FERTILIZATION. It normally requires exposing the sperm to the female genital tract for a period of time to bring about increased SPERM MOTILITY and the ACROSOME REACTION before fertilization in the FALLOPIAN TUBES can take place.Insulin: A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.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.Protein Tyrosine Phosphatase, Non-Receptor Type 13: A subtype of non-receptor protein tyrosine phosphatases that is characterized by the presence of an amino-terminal FERM domain, an intervening region containing five different PDZ domains, and a carboxyl-terminal phosphatase domain. In addition to playing a role as a regulator of the FAS RECEPTOR activity this subtype interacts via its PDZ and FERM domains with a variety of INTRACELLULAR SIGNALING PROTEINS and CYTOSKELETAL PROTEINS.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.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)Oncogene Protein v-cbl: An oncoprotein from the Cas NS-1 murine retrovirus that induces pre- B-CELL LYMPHOMA and MYELOID LEUKEMIAS. v-cbl protein is a tyrosine-phosphorylated, truncated form of its cellular homologue, PROTO-ONCOGENE PROTEIN C-CBL.Arsenicals: Inorganic or organic compounds that contain arsenic.Antigens, CD45: High-molecular weight glycoproteins uniquely expressed on the surface of LEUKOCYTES and their hemopoietic progenitors. They contain a cytoplasmic protein tyrosine phosphatase activity which plays a role in intracellular signaling from the CELL SURFACE RECEPTORS. The CD45 antigens occur as multiple isoforms that result from alternative mRNA splicing and differential usage of three exons.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Oncogene Proteins v-abl: Transforming proteins encoded by the abl oncogenes. Oncogenic transformation of c-abl to v-abl occurs by insertional activation that results in deletions of specific N-terminal amino acids.ras GTPase-Activating Proteins: PROTEINS that specifically activate the GTP-phosphohydrolase activity of RAS PROTEINS.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Organophosphorus Compounds: Organic compounds that contain phosphorus as an integral part of the molecule. Included under this heading is broad array of synthetic compounds that are used as PESTICIDES and DRUGS.Acid Phosphatase: An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC Techniques: Techniques for removal by adsorption and subsequent elution of a specific antibody or antigen using an immunosorbent containing the homologous antigen or antibody.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Receptor, EphA3: An eph family receptor that is found primarily in adult BRAIN and variety of tissues in the developing embryo tissues. During embryonic development high levels of EphA3 receptor expression is seen in the nervous system and coincides with neuronal cell migration, suggesting a role for this protein in axonal pathfinding.Antibodies, Phospho-Specific: Antibodies directed against immunogen-coupled phosphorylated PEPTIDES corresponding to amino acids surrounding the PHOSPHORYLATION site. They are used to study proteins involved in SIGNAL TRANSDUCTION pathways. (From Methods Mol Biol 2000; 99:177-89)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.Calcium-Calmodulin-Dependent Protein Kinases: A CALMODULIN-dependent enzyme that catalyzes the phosphorylation of proteins. This enzyme is also sometimes dependent on CALCIUM. A wide range of proteins can act as acceptor, including VIMENTIN; SYNAPSINS; GLYCOGEN SYNTHASE; MYOSIN LIGHT CHAINS; and the MICROTUBULE-ASSOCIATED PROTEINS. (From Enzyme Nomenclature, 1992, p277)GTPase-Activating Proteins: Proteins that activate the GTPase of specific GTP-BINDING PROTEINS.Oncogene Proteins v-raf: A family of transforming proteins isolated from retroviruses such as MOUSE SARCOMA VIRUSES. They are viral-derived members of the raf-kinase family of serine-theonine kinases.Phosphoric Monoester Hydrolases: A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate. EC 3.1.3.Lactams, Macrocyclic: LACTAMS forming compounds with a ring size of approximately 1-3 dozen atoms.Tungsten Compounds: Inorganic compounds that contain tungsten as an integral part of the molecule.Nerve Tissue ProteinsZAP-70 Protein-Tyrosine Kinase: A protein tyrosine kinase that is required for T-CELL development and T-CELL ANTIGEN RECEPTOR function.Yersinia: A genus of gram-negative, facultatively anaerobic rod- to coccobacillus-shaped bacteria that occurs in a broad spectrum of habitats.Benzoquinones: Benzene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Mitogen-Activated Protein Kinases: A superfamily of PROTEIN-SERINE-THREONINE KINASES that are activated by diverse stimuli via protein kinase cascades. They are the final components of the cascades, activated by phosphorylation by MITOGEN-ACTIVATED PROTEIN KINASE KINASES, which in turn are activated by mitogen-activated protein kinase kinase kinases (MAP KINASE KINASE KINASES).DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Oligopeptides: Peptides composed of between two and twelve amino acids.Oncogene Proteins: Proteins coded by oncogenes. They include proteins resulting from the fusion of an oncogene and another gene (ONCOGENE PROTEINS, FUSION).Cell Line, Transformed: Eukaryotic cell line obtained in a quiescent or stationary phase which undergoes conversion to a state of unregulated growth in culture, resembling an in vitro tumor. It occurs spontaneously or through interaction with viruses, oncogenes, radiation, or drugs/chemicals.Quinones: Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.Proto-Oncogene Proteins c-crk: Signal transducing adaptor proteins that contain SRC HOMOLOGY DOMAINS and play a role in CYTOSKELETON reorganization. c-crk protein is closely related to ONCOGENE PROTEIN V-CRK and includes several alternatively spliced isoforms.Proto-Oncogene Proteins c-bcr: Proto-oncogene protein bcr is a serine-threonine kinase that functions as a negative regulator of CELL PROLIFERATION and NEOPLASTIC CELL TRANSFORMATION. It is commonly fused with cellular abl protein to form BCR-ABL FUSION PROTEINS in PHILADELPHIA CHROMOSOME positive LEUKEMIA patients.Phosphotransferases (Alcohol Group Acceptor): A group of enzymes that transfers a phosphate group onto an alcohol group acceptor. EC 2.7.1.Mitogen-Activated Protein Kinase 1: A proline-directed serine/threonine protein kinase which mediates signal transduction from the cell surface to the nucleus. Activation of the enzyme by phosphorylation leads to its translocation into the nucleus where it acts upon specific transcription factors. p40 MAPK and p41 MAPK are isoforms.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.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Jurkat Cells: A CELL LINE derived from human T-CELL LEUKEMIA and used to determine the mechanism of differential susceptibility to anti-cancer drugs and radiation.Protein Tyrosine Phosphatase, Non-Receptor Type 3: A subtype of non-receptor protein tyrosine phosphatases that is characterized by the presence of an amino-terminal FERM domain, an intervening region containing one or more PDZ domains, and a carboxyl-terminal phosphatase domain. Expression of this phosphatase subtype has been observed in BONE MARROW; fetal LIVER; LYMPH NODES; and T LYMPHOCYTES.STAT3 Transcription Factor: A signal transducer and activator of transcription that mediates cellular responses to INTERLEUKIN-6 family members. STAT3 is constitutively activated in a variety of TUMORS and is a major downstream transducer for the CYTOKINE RECEPTOR GP130.Tetradecanoylphorbol Acetate: A phorbol ester found in CROTON OIL with very effective tumor promoting activity. It stimulates the synthesis of both DNA and RNA.Chick Embryo: The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.Phosphotransferases: A rather large group of enzymes comprising not only those transferring phosphate but also diphosphate, nucleotidyl residues, and others. These have also been subdivided according to the acceptor group. (From Enzyme Nomenclature, 1992) EC 2.7.Cytoplasm: The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)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.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.Enzyme Precursors: Physiologically inactive substances that can be converted to active enzymes.Calcium: 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.Proto-Oncogene Proteins c-yes: Members of the src-family tyrosine kinases that are activated during the transition from G2 PHASE to M PHASE of the CELL CYCLE. It is highly homologous to PROTO-ONCOGENE PROTEIN PP60(C-SRC).Organophosphates: Carbon-containing phosphoric acid derivatives. Included under this heading are compounds that have CARBON atoms bound to one or more OXYGEN atoms of the P(=O)(O)3 structure. Note that several specific classes of endogenous phosphorus-containing compounds such as NUCLEOTIDES; PHOSPHOLIPIDS; and PHOSPHOPROTEINS are listed elsewhere.Tyrphostins: A family of synthetic protein tyrosine kinase inhibitors. They selectively inhibit receptor autophosphorylation and are used to study receptor function.Point Mutation: A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.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.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Ephrin-A5: A GLYCOINOSITOL PHOSPHOLIPID MEMBRANE ANCHOR containing ephrin found in developing tectum. It has been shown to mediate the bundling of cortical axons and repel the axonal growth of retinal ganglia axons. It is found in a variety of adult tissues of BRAIN; HEART; and KIDNEY.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.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).Receptor-Like Protein Tyrosine Phosphatases, Class 4: A subclass of receptor-like protein tryosine phosphatases that contain short highly glycosylated extracellular domains and two active cytosolic protein tyrosine phosphatase domains.Receptors, Antigen, T-Cell: Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (ANTIGENS, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains.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).Retroviridae Proteins: Proteins from the family Retroviridae. The most frequently encountered member of this family is the Rous sarcoma virus protein.Protein Processing, Post-Translational: Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.Receptor Aggregation: Chemically stimulated aggregation of cell surface receptors, which potentiates the action of the effector cell.Isoflavones: 3-Phenylchromones. Isomeric form of FLAVONOIDS in which the benzene group is attached to the 3 position of the benzopyran ring instead of the 2 position.Fusion Proteins, bcr-abl: Translation products of a fusion gene derived from CHROMOSOMAL TRANSLOCATION of C-ABL GENES to the genetic locus of the breakpoint cluster region gene on chromosome 22. Several different variants of the bcr-abl fusion proteins occur depending upon the precise location of the chromosomal breakpoint. These variants can be associated with distinct subtypes of leukemias such as PRECURSOR CELL LYMPHOBLASTIC LEUKEMIA-LYMPHOMA; LEUKEMIA, MYELOGENOUS, CHRONIC, BCR-ABL POSITIVE; and NEUTROPHILIC LEUKEMIA, CHRONIC.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.Oncogene Proteins v-erbB: Transforming proteins encoded by erbB oncogenes from the avian erythroblastosis virus. The protein is a truncated form of the EGF receptor (RECEPTOR, EPIDERMAL GROWTH FACTOR) whose kinase domain is constitutively activated by deletion of the ligand-binding domain.Diamide: A sulfhydryl reagent which oxidizes sulfhydryl groups to the disulfide form. It is a radiation-sensitizing agent of anoxic bacterial and mammalian cells.Serine: A non-essential amino acid occurring in natural form as the L-isomer. It is synthesized from GLYCINE or THREONINE. It is involved in the biosynthesis of PURINES; PYRIMIDINES; and other amino acids.Two-Hybrid System Techniques: Screening techniques first developed in yeast to identify genes encoding interacting proteins. Variations are used to evaluate interplay between proteins and other molecules. Two-hybrid techniques refer to analysis for protein-protein interactions, one-hybrid for DNA-protein interactions, three-hybrid interactions for RNA-protein interactions or ligand-based interactions. Reverse n-hybrid techniques refer to analysis for mutations or other small molecules that dissociate known interactions.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Pyrones: Keto-pyrans.Octoxynol: Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Octoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide.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.Proto-Oncogene Proteins c-ret: Receptor protein-tyrosine kinases involved in the signaling of GLIAL CELL-LINE DERIVED NEUROTROPHIC FACTOR ligands. They contain an extracellular cadherin domain and form a receptor complexes with GDNF RECEPTORS. Mutations in ret protein are responsible for HIRSCHSPRUNG DISEASE and MULTIPLE ENDOCRINE NEOPLASIA TYPE 2.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.Proteomics: The systematic study of the complete complement of proteins (PROTEOME) of organisms.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.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.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.PC12 Cells: A CELL LINE derived from a PHEOCHROMOCYTOMA of the rat ADRENAL MEDULLA. PC12 cells stop dividing and undergo terminal differentiation when treated with NERVE GROWTH FACTOR, making the line a useful model system for NERVE CELL differentiation.Protein Kinase C: An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.Trypsin: A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC Transcription Factor: A signal transducer and activator of transcription that mediates cellular responses to a variety of CYTOKINES. Stat5 activation is associated with transcription of CELL CYCLE regulators such as CYCLIN KINASE INHIBITOR P21 and anti-apoptotic genes such as BCL-2 GENES. Stat5 is constitutively activated in many patients with acute MYELOID LEUKEMIA.Phosphates: Inorganic salts of phosphoric acid.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.Chromatography, Affinity: A chromatographic technique that utilizes the ability of biological molecules to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Amyloid beta-Protein Precursor: A single-pass type I membrane protein. It is cleaved by AMYLOID PRECURSOR PROTEIN SECRETASES to produce peptides of varying amino acid lengths. A 39-42 amino acid peptide, AMYLOID BETA-PEPTIDES is a principal component of the extracellular amyloid in SENILE PLAQUES.Subcellular Fractions: Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Caseins: A mixture of related phosphoproteins occurring in milk and cheese. The group is characterized as one of the most nutritive milk proteins, containing all of the common amino acids and rich in the essential ones.Janus Kinase 2: A Janus kinase subtype that is involved in signaling from GROWTH HORMONE RECEPTORS; PROLACTIN RECEPTORS; and a variety of CYTOKINE RECEPTORS such as ERYTHROPOIETIN RECEPTORS and INTERLEUKIN RECEPTORS. Dysregulation of Janus kinase 2 due to GENETIC TRANSLOCATIONS have been associated with a variety of MYELOPROLIFERATIVE DISORDERS.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.

Role of alphavbeta3 integrin in the activation of vascular endothelial growth factor receptor-2. (1/3233)

Interaction between integrin alphavbeta3 and extracellular matrix is crucial for endothelial cells sprouting from capillaries and for angiogenesis. Furthermore, integrin-mediated outside-in signals co-operate with growth factor receptors to promote cell proliferation and motility. To determine a potential regulation of angiogenic inducer receptors by the integrin system, we investigated the interaction between alphavbeta3 integrin and tyrosine kinase vascular endothelial growth factor receptor-2 (VEGFR-2) in human endothelial cells. We report that tyrosine-phosphorylated VEGFR-2 co-immunoprecipitated with beta3 integrin subunit, but not with beta1 or beta5, from cells stimulated with VEGF-A165. VEGFR-2 phosphorylation and mitogenicity induced by VEGF-A165 were enhanced in cells plated on the alphavbeta3 ligand, vitronectin, compared with cells plated on the alpha5beta1 ligand, fibronectin or the alpha2beta1 ligand, collagen. BV4 anti-beta3 integrin mAb, which does not interfere with endothelial cell adhesion to vitronectin, reduced (i) the tyrosine phosphorylation of VEGFR-2; (ii) the activation of downstream transductor phosphoinositide 3-OH kinase; and (iii) biological effects triggered by VEGF-A165. These results indicate a new role for alphavbeta3 integrin in the activation of an in vitro angiogenic program in endothelial cells. Besides being the most important survival system for nascent vessels by regulating cell adhesion to matrix, alphavbeta3 integrin participates in the full activation of VEGFR-2 triggered by VEGF-A, which is an important angiogenic inducer in tumors, inflammation and tissue regeneration.  (+info)

Involvement of tyrosine phosphorylation in HMG-CoA reductase inhibitor-induced cell death in L6 myoblasts. (2/3233)

Our previous studies have shown that the HMG-CoA reductase (HCR) inhibitor (HCRI), simvastatin, causes myopathy in rabbits and kills L6 myoblasts. The present study was designed to elucidate the molecular mechanism of HCRI-induced cell death. We have demonstrated that simvastatin induces the tyrosine phosphorylation of several cellular proteins within 10 min. These phosphorylations were followed by apoptosis, as evidenced by the occurrence of internucleosomal DNA fragmentation and by morphological changes detected with Nomarski optics. Simvastatin-induced cell death was prevented by tyrosine kinase inhibitors. The MTT assay revealed that the addition of mevalonic acid into the culture medium partially inhibited simvastatin-induced cell death. Thus, these results suggested that protein tyrosine phosphorylation might play an important role in the intracellular signal transduction pathway mediating the HCRI-induced death of myoblasts.  (+info)

Phosphotyrosine binding domains of Shc and insulin receptor substrate 1 recognize the NPXpY motif in a thermodynamically distinct manner. (3/3233)

Phosphotyrosine binding (PTB) domains of the adaptor protein Shc and insulin receptor substrate (IRS-1) interact with a distinct set of activated and tyrosine-phosphorylated cytokine and growth factor receptors and play important roles in mediating mitogenic signal transduction. By using the technique of isothermal titration calorimetry, we have studied the thermodynamics of binding of the Shc and IRS-1 PTB domains to tyrosine-phosphorylated NPXY-containing peptides derived from known receptor binding sites. The results showed that relative contributions of enthalpy and entropy to the free energy of binding are dependent on specific phosphopeptides. Binding of the Shc PTB domain to tyrosine-phosphorylated peptides from TrkA, epidermal growth factor, ErbB3, and insulin receptors is achieved via an overall entropy-driven reaction. On the other hand, recognition of the phosphopeptides of insulin and interleukin-4 receptors by the IRS-1 PTB domain is predominantly an enthalpy-driven process. Mutagenesis and amino acid substitution experiments showed that in addition to the tyrosine-phosphorylated NPXY motif, the PTB domains of Shc and IRS-1 prefer a large hydrophobic residue at pY-5 and a small hydrophobic residue at pY-1, respectively (where pY is phosphotyrosine). These results agree with the calculated solvent accessibility of these two key peptide residues in the PTB domain/peptide structures and support the notion that the PTB domains of Shc and IRS-1 employ functionally distinct mechanisms to recognize tyrosine-phosphorylated receptors.  (+info)

In situ detection of activated Bruton's tyrosine kinase in the Ig signaling complex by phosphopeptide-specific monoclonal antibodies. (4/3233)

Bruton's tyrosine kinase (Btk) is a critical transducer of signals originating from the B cell antigen receptor (BCR). Dosage, sequential phosphorylation, and protein interactions are interdependent mechanisms influencing Btk function. Phosphopeptide-specific mAbs recognizing two distinct phosphotyrosine modifications were used to quantify Btk activation by immunofluorescent techniques during B cell stimulation. In a population of cultured B cells stimulated by BCR crosslinking and analyzed by flow cytometry, transient phosphorylation of the regulatory Btk tyrosine residues (551Y and 223Y) was detected. The kinetics of phosphorylation of the residues were temporally distinct. Tyrosine 551, a transactivating substrate site for Src-family kinases, was maximally phosphorylated within approximately 30 seconds of stimulation as monitored by flow cytometry. Tyrosine 223, an autophosphorylation site within the SH3 domain, was maximally phosphorylated at approximately 5 minutes. Btk returned to a low tyrosine phosphorylation level within 30 minutes, despite persistent elevation of global tyrosine phosphorylation. Colocalization of activated Btk molecules with the crosslinked BCR signaling complex was observed to coincide with the period of maximal Btk tyrosine phosphorylation when stimulated B cells were analyzed with confocal microscopy. The results of these in situ temporal and spatial analyses imply that Btk signaling occurs in the region of the Ig receptor signaling complex, suggesting a similar location for downstream targets of its activity.  (+info)

Increased insulin sensitivity and obesity resistance in mice lacking the protein tyrosine phosphatase-1B gene. (5/3233)

Protein tyrosine phosphatase-1B (PTP-1B) has been implicated in the negative regulation of insulin signaling. Disruption of the mouse homolog of the gene encoding PTP-1B yielded healthy mice that, in the fed state, had blood glucose concentrations that were slightly lower and concentrations of circulating insulin that were one-half those of their PTP-1B+/+ littermates. The enhanced insulin sensitivity of the PTP-1B-/- mice was also evident in glucose and insulin tolerance tests. The PTP-1B-/- mice showed increased phosphorylation of the insulin receptor in liver and muscle tissue after insulin injection in comparison to PTP-1B+/+ mice. On a high-fat diet, the PTP-1B-/- and PTP-1B+/- mice were resistant to weight gain and remained insulin sensitive, whereas the PTP-1B+/+ mice rapidly gained weight and became insulin resistant. These results demonstrate that PTP-1B has a major role in modulating both insulin sensitivity and fuel metabolism, thereby establishing it as a potential therapeutic target in the treatment of type 2 diabetes and obesity.  (+info)

Interferon-alpha activates multiple STAT proteins and upregulates proliferation-associated IL-2Ralpha, c-myc, and pim-1 genes in human T cells. (6/3233)

Interferon-alpha (IFN-alpha) is a pleiotropic cytokine that has antiviral, antiproliferative, and immunoregulatory functions. There is increasing evidence that IFN-alpha has an important role in T-cell biology. We have analyzed the expression of IL-2Ralpha, c-myc, and pim-1 genes in anti-CD3-activated human T lymphocytes. The induction of these genes is associated with interleukin-2 (IL-2)-induced T-cell proliferation. Treatment of T lymphocytes with IFN-alpha, IL-2, IL-12, and IL-15 upregulated IL-2Ralpha, c-myc, and pim-1 gene expression. IFN-alpha also sensitized T cells to IL-2-induced proliferation, further suggesting that IFN-alpha may be involved in the regulation of T-cell mitogenesis. When we analyzed the nature of STAT proteins capable of binding to IL-2Ralpha, pim-1, and IRF-1 GAS elements after cytokine stimulation, we observed IFN-alpha-induced binding of STAT1, STAT3, and STAT4, but not STAT5 to all of these elements. Yet, IFN-alpha was able to activate binding of STAT5 to the high-affinity IFP53 GAS site. IFN-alpha enhanced tyrosine phosphorylation of STAT1, STAT3, STAT4, STAT5a, and STAT5b. IL-12 induced STAT4 and IL-2 and IL-15 induced STAT5 binding to the GAS elements. Taken together, our results suggest that IFN-alpha, IL-2, IL-12, and IL-15 have overlapping activities on human T cells. These findings thus emphasize the importance of IFN-alpha as a T-cell regulatory cytokine.  (+info)

Involvement of wiskott-aldrich syndrome protein in B-cell cytoplasmic tyrosine kinase pathway. (7/3233)

Bruton's tyrosine kinase (Btk) has been shown to play a role in normal B-lymphocyte development. Defective expression of Btk leads to human and murine immunodeficiencies. However, the exact role of Btk in the cytoplasmic signal transduction in B cells is still unclear. This study represents a search for the substrate for Btk in vivo. We identified one of the major phosphoproteins associated with Btk in the preB cell line NALM6 as the Wiskott-Aldrich syndrome protein (WASP), the gene product responsible for Wiskott-Aldrich syndrome, which is another hereditary immunodeficiency with distinct abnormalities in hematopoietic cells. We demonstrated that WASP was transiently tyrosine-phosphorylated after B-cell antigen receptor cross-linking on B cells, suggesting that WASP is located downstream of cytoplasmic tyrosine kinases. An in vivo reconstitution system demonstrated that WASP is physically associated with Btk and can serve as the substrate for Btk. A protein binding assay suggested that the tyrosine-phosphorylation of WASP alters the association between WASP and a cellular protein. Furthermore, identification of the phosphorylation site of WASP in reconstituted cells allowed us to evaluate the catalytic specificity of Btk, the exact nature of which is still unknown.  (+info)

Expression of the erythropoietin receptor by trophoblast cellsin the human placenta. (8/3233)

Nonclassical sites of erythropoietin (EPO) and erythropoietin receptor (EPO-R) expression have been described that suggest new physiological roles for this hormone unrelated to erythropoiesis. The recent finding of EPO expression by trophoblast cells in the human placenta prompted us to consider whether these cells also express EPO-R. With use of immunocytochemistry, EPO-R was identified in villous and extravillous cytotrophoblast cells, as well as in the syncytiotrophoblast at all gestational ages. EPO-R was also expressed by cells within the villous core, including endothelial cells of fetoplacental blood vessels. Placental tissues and isolated and immunopurified trophoblast cells, as well as trophoblast-derived choriocarcinoma Jar cells, expressed immunoreactive EPO-R on Western blot. EPO-R mRNA was also detected in the same placental tissues and trophoblast cells by nested-primer reverse transcription-polymerase chain reaction. Finally, EPO-R was functional insofar as the receptor was phosphorylated on tyrosine residues in response to exogenous EPO treatment of cultured trophoblast or Jar cells. Thus, the present findings support the hypothesis that trophoblast cells of the human placenta express EPO-R. In view of these results, taken together with previous work demonstrating EPO expression by the same cells, an autocrine role for this hormone in the survival, proliferation, or differentiation of placental trophoblast cells is proposed.  (+info)

  • Each lane represents immunoprecipitated phosphotyrosine proteins from 1000 μg of cell lysate. (
  • Detection of PTP lb-dependent phosphotyrosine sites on lipid metabolic proteins initiated global lipidomics characterization of corresponding liver samples and revealed altered fatty acid and triglyceride metabolism in L-PTPlb-/- mice. (
  • Proteins encoding phosphotyrosine binding (PTB) domains function as adaptors or scaffolds to organize the signaling complexes involved in wide-ranging physiological processes including neural development, immunity, tissue homeostasis and cell growth. (
  • The phosphotyrosine Rac1 profile (performed using kit BK160) revealed a modification pattern in which Rac1 tyrosyl phosphorylation was rapidly reduced from basal levels after EGF treatment (0.5-1 min) thereafter returning to basal levels. (
  • As in HeLa or 3T3 cells infected with EPEC, Tir and phosphotyrosine colocalized with intense actin staining directly beneath attached bacteria on RBC treated with extract (Figure 2A). (
  • Quantitation of colocalization of Tir with phosphotyrosine and actin staining (see Materials and Methods) indicated that of those bacteria attached to RBC and expressing Tir, ∼60% were colocalized with phosphotyrosine (Figure 2B), and ∼45% with phosphotyrosine and intense actin staining (Figure 2C) following exposure to extract. (
  • Tyrosine phosphorylation regulates multi-layered signaling networks with broad implications in (patho)physiology, but high-throughput methods for functional annotation of phosphotyrosine sites are lacking. (
  • Use of an inhibitor of protein-tyrosine kinases to deplete tip phosphotyrosine also caused disappearance of beta 1 integrin from the tip, suggesting a role for tyrosine phosphorylation in facilitating interaction of growth cones with certain environmental cues by fostering the aggregation of receptors in filopodia. (
  • We integrated a quantitative phosphotyrosine profiling method with "spike-in" stable isotope labeling with amino acids in cell culture (SILAC) and quantified 1394 class I phosphorylation sites in 16 ALL xenografts. (
  • The phosphotyrosine Rac1 profile (performed using kit BK160) revealed a modification pattern in which Rac1 tyrosyl phosphorylation was rapidly reduced from basal levels after EGF treatment (0.5-1 min) thereafter returning to basal levels. (
  • The antibodies, which have demonstrated affinity for a variety of molecules containing o-phosphotyrosine residues, were prepared using a synthetic analog, p-azobenzyl phosphonate (ABP) covalently linked to a carrier protein, as the antigen. (
  • Monoclonal antibodies to phosphotyrosine. (
  • To address this issue, we synthesized phospho- and non-phosphopeptides representing each predominant Western CagA EPIYA-motif, and determined the recognition patterns of seven different phosphotyrosine antibodies in Western blots, and also performed infection studies with diverse representative Western H. pylori strains. (
  • Phosphotyrosine (pTyr) signaling, which plays a central role in cell-cell and cell-environment interactions, has been considered to be an evolutionary innovation in multicellular metazoans. (
  • We recently identified a novel adaptor protein, termed dual adaptor for phosphotyrosine and 3-phosphoinositides (DAPP1), that possesses a Src homology (SH2) domain and a pleckstrin homology (PH) domain. (
  • Both effectors contain an N-terminal Bin/Amphiphysin/Rvs (BAR) domain, a central pleckstrin homology (PH) domain, and a C-terminal phosphotyrosine binding (PTB) domain, and they bind the Rab5 through the BAR domain. (
  • These results suggest that cytoskeleton-associated phosphotyrosine kinase(s) and their substrates may play a role in growth and differentiation of adult intestinal epithelial cells. (
  • This assay semi-quantitatively measures phosphotyrosine EphB4 in lysate samples. (
  • To extend these findings to p130, the major phosphotyrosine-containing protein in CT10-transformed cells, we utilized a nitrocellulose filter binding assay. (
  • Reacts with phosphotyrosine, and detects the presence of phosphotyrosine in both un-stimulated and stimulated cell lysates. (
  • Phosphotyrosine, alanine and glyceine in a 1:1:1 ratio polymerized in the presence of keyhole limpet hemocyanin with 1-ethyl-3-(3'-dimentrylaminopropyl) carbodiimide reacts with phosphotyrosine, and detects the presence of phosphotyrosine in both un-stimulated and stimulated cell lysates. (
  • The phosphotyrosine-binding domain of PKCθ interacts with the kinase Zap70 and is required for early TCR signaling. (
  • Therefore, this study highlights the application and potential of phosphotyrosine profiling for identifying clinically relevant kinase targets in leukemia. (
  • Furthermore, in insulin-resistant rodent skeletal muscle, the decrease in total phosphotyrosine-associated phosphoinositide 3-kinase (PI 3-kinase) activity closely parallels the reduction in IRS-1-associated PI 3-kinase activity ( 13 ). (
  • Specific suppression of focal adhesion kinase activity (without global decreases in phosphotyrosine) was shown to precede induction of apoptosis, which was responsible for growth inhibition in adherent cells. (
  • Two arginines in this domain are responsible for hydrogen bonding phosphotyrosine residues on an Ac-LYASSNPApY-NH2 peptide in the juxtamembrane region of the insulin receptor. (
  • 1998) Distinct Involvement of Beta3 Integrin Cytoplasmic Domain Tyrosine Residues 747 and 759 in Integrin-Mediated Cytoskeletal Assembly and Phosphotyrosine Signaling. (
  • Treatment of the KIT-expressing SCLC-derived NCI-H526 cell line in vitro with SU11248 resulted in dose-dependent inhibition of stem cell factor-stimulated KIT phosphotyrosine levels and proliferation. (
  • To study the global dynamics of phosphotyrosine-based signaling events in early growth factor stimulation, we developed a mass spectrometric method that converts temporal changes to differences in peptide isotopic abundance. (
  • The phosphotyrosine is known to hold fragments of the peptide together via strong ionic interactions. (
  • To elucidate these mechanisms, we performed a quantitative comparison of the phosphotyrosine signaling network and resulting phenotypes triggered by IL-2 and IL-15. (
  • The phosphotyrosine-binding domain (PTB, also phosphotyrosine-interaction or PI domain) in the protein tensin tends to be found at the C-terminus. (
  • The phosphotyrosine-binding domain of insulin receptor substrate-1 is not related to the phosphotyrosine-binding domain of tensin. (
  • Nick J. Wardle, Harry R. Hudson and S. W. Annie Bligh, " O-Phosphotyrosine Analogues: Synthesis and Therapeutic Role in Modulation of Signal Transduction", Current Organic Chemistry (2010) 14: 426. (
  • These data are consistent with a direct role of SH2 in the modulation of cellular phosphotyrosine status in vivo. (
  • We applied a phosphosite-set-enrichment analysis to identify known and novel pathways exhibiting PTP1b- and diet-dependent phosphotyrosine regulation. (
  • The interactions were further shown to form an unusually dense, monolithic network with a central core and reflect and expand phosphotyrosine-related KEGG pathways. (
  • The purified fusion enzyme catalyzed the removal of phosphate from p-nitrophenylphosphate (PNPP), phosphotyrosine (PY), and a commercial phosphopeptide containing a single phosphotyrosine residue but did not cleave phosphoserine or phosphothreonine. (
  • Functional studies coupled with structural analysis define a myristoyl/phosphotyrosine switch in c-Abl that regulates docking and accessibility of the SH2 domain. (
  • 1995) Structure and Ligand Recognition of the Phosphotyrosine Binding Domain of Shc. (
  • The disabled 1 phosphotyrosine-binding domain binds to the internalization signals of transmembrane glycoproteins and to phospholipids. (
  • beta 1 integrin, a subunit of the receptor for laminin-type neurite growth promoters, coconcentrated with phosphotyrosine at filopodial tips of both Aplysia and mouse growth cones. (
  • Several observations indicated that the association of beta 1 integrin with phosphotyrosine is close. (
  • beta 1 integrin and phosphotyrosine are known to colocalize at focal contacts, sites of adhesion of cells to the extracellular matrix, but the composition and behavior of the tip aggregates mark them as distinct structures. (