Phospholipase D: An enzyme found mostly in plant tissue. It hydrolyzes glycerophosphatidates with the formation of a phosphatidic acid and a nitrogenous base such as choline. This enzyme also catalyzes transphosphatidylation reactions. EC Acids: Fatty acid derivatives of glycerophosphates. They are composed of glycerol bound in ester linkage with 1 mole of phosphoric acid at the terminal 3-hydroxyl group and with 2 moles of fatty acids at the other two hydroxyl groups.Glycerophospholipids: Derivatives of phosphatidic acid in which the hydrophobic regions are composed of two fatty acids and a polar alcohol is joined to the C-3 position of glycerol through a phosphodiester bond. They are named according to their polar head groups, such as phosphatidylcholine and phosphatidylethanolamine.Phospholipases: A class of enzymes that catalyze the hydrolysis of phosphoglycerides or glycerophosphatidates. EC 3.1.-.Phospholipases A2: Phospholipases that hydrolyze the acyl group attached to the 2-position of PHOSPHOGLYCERIDES.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.1-Butanol: A four carbon linear hydrocarbon that has a hydroxy group at position 1.Phospholipases A: Phospholipases that hydrolyze one of the acyl groups of phosphoglycerides or glycerophosphatidates.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.Phosphoinositide Phospholipase C: A type C phospholipase with specificity towards PHOSPHATIDYLINOSITOLS that contain INOSITOL 1,4,5-TRISPHOSPHATE. Many of the enzymes listed under this classification are involved in intracellular signaling.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.DiglyceridesPhospholipase C beta: A phosphoinositide phospholipase C subtype that is primarily regulated by its association with HETEROTRIMERIC G-PROTEINS. It is structurally related to PHOSPHOLIPASE C DELTA with the addition of C-terminal extension of 400 residues.Butanols: Isomeric forms and derivatives of butanol (C4H9OH).ADP-Ribosylation Factors: MONOMERIC GTP-BINDING PROTEINS that were initially recognized as allosteric activators of the MONO(ADP-RIBOSE) TRANSFERASE of the CHOLERA TOXIN catalytic subunit. They are involved in vesicle trafficking and activation of PHOSPHOLIPASE D. This enzyme was formerly listed as EC A2 Inhibitors: Compounds that inhibit or block the activity of a PHOSPHOLIPASE A2 enzyme.Phosphatidylinositol Diacylglycerol-Lyase: A phosphorus-oxygen lyase found primarily in BACTERIA. The enzyme catalyzes the cleavage of a phosphoester linkage in 1-phosphatidyl-1D-myo-inositol to form 1D-myo-inositol 1,2-cyclic phosphate and diacylglycerol. The enzyme was formerly classified as a phosphoric diester hydrolase (EC and is often referred to as a TYPE C PHOSPHOLIPASES. However it is now known that a cyclic phosphate is the final product of this enzyme and that water does not enter into the reaction.Phosphatidylcholines: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.Phospholipases A1: A phospholipase that hydrolyzes the acyl group attached to the 1-position of PHOSPHOGLYCERIDES.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.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Phosphatidylinositols: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to the hexahydroxy alcohol, myo-inositol. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid, myo-inositol, and 2 moles of fatty acids.Phospholipase C delta: A phosphoinositide phospholipase C subtype that is structurally defined by the presence of an N-terminal pleckstrin-homology and EF-hand domains, a central catalytic domain, and a C-terminal calcium-dependent membrane-binding domain.Phosphatidylinositol 4,5-Diphosphate: A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase C, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (Kendrew, The Encyclopedia of Molecular Biology, 1994)Receptors, Phospholipase A2: Cell surface receptors that bind to and internalize SECRETED PHOSPHOLIPASES A2. Although primarily acting as scavenger receptors, these proteins may also play a role in intracellular signaling. Soluble forms of phospholipase A2 receptors occur through the action of proteases and may a play a role in the inhibition of extracellular phospholipase activity.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.Tetradecanoylphorbol Acetate: A phorbol ester found in CROTON OIL with very effective tumor promoting activity. It stimulates the synthesis of both DNA and RNA.Arachidonic Acid: An unsaturated, essential fatty acid. It is found in animal and human fat as well as in the liver, brain, and glandular organs, and is a constituent of animal phosphatides. It is formed by the synthesis from dietary linoleic acid and is a precursor in the biosynthesis of prostaglandins, thromboxanes, and leukotrienes.Phospholipids: 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.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Guanosine 5'-O-(3-Thiotriphosphate): Guanosine 5'-(trihydrogen diphosphate), monoanhydride with phosphorothioic acid. A stable GTP analog which enjoys a variety of physiological actions such as stimulation of guanine nucleotide-binding proteins, phosphoinositide hydrolysis, cyclic AMP accumulation, and activation of specific proto-oncogenes.Group IV Phospholipases A2: A cytosolic phospholipase A2 group that plays an important role in the release of free ARACHIDONIC ACID, which in turn is metabolized to PROSTAGLANDINS by the CYCLOOXYGENASE pathway and to LEUKOTRIENES by the 5-LIPOXYGENASE pathway.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.Group II Phospholipases A2: A subcategory of secreted phospholipases A2 that includes enzymes isolated from a variety of sources. The creation of this group is based upon similarities in the structural determinants of the enzymes including a negatively charged carboxy-terminal segment.GTP-Binding Proteins: Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.ADP-Ribosylation Factor 1: ADP-RIBOSYLATION FACTOR 1 is involved in regulating intracellular transport by modulating the interaction of coat proteins with organelle membranes in the early secretory pathway. It is a component of COAT PROTEIN COMPLEX I. This enzyme was formerly listed as EC Unsaturated derivatives of the ESTRANES with methyl groups at carbon-13, with no carbon at carbon-10, and with no more than one carbon at carbon-17. They must contain one or more double bonds.Lysophospholipase: An enzyme that catalyzes the hydrolysis of a single fatty acid ester bond in lysoglycerophosphatidates with the formation of glyceryl phosphatidates and a fatty acid. EC The rate dynamics in chemical or physical systems.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.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.Phosphoric Diester Hydrolases: A class of enzymes that catalyze the hydrolysis of one of the two ester bonds in a phosphodiester compound. EC 3.1.4.Choline: A basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism.Phospholipases A2, Secretory: A subcategory of phospholipases A2 that are secreted from cells. They are 14 kDa proteins containing multiple disulfide-bonds and access their substrate via an interfacial binding site that interacts with phospholipid membranes. In addition specific PHOSPHOLIPASE A2 RECEPTORS can bind to and internalize the enzymes.Lysophosphatidylcholines: Derivatives of PHOSPHATIDYLCHOLINES obtained by their partial hydrolysis which removes one of the fatty acid moieties.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Phosphatidylethanolamines: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids.Protein Kinase C-alpha: A cytoplasmic serine threonine kinase involved in regulating CELL DIFFERENTIATION and CELLULAR PROLIFERATION. Overexpression of this enzyme has been shown to promote PHOSPHORYLATION of BCL-2 PROTO-ONCOGENE PROTEINS and chemoresistance in human acute leukemia cells.Lysophospholipids: Derivatives of PHOSPHATIDIC ACIDS that lack one of its fatty acyl chains due to its hydrolytic removal.Pyrrolidinones: A group of compounds that are derivatives of oxo-pyrrolidines. A member of this group is 2-oxo pyrrolidine, which is an intermediate in the manufacture of polyvinylpyrrolidone. (From Merck Index, 11th ed)Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Inositol Phosphates: Phosphoric acid esters of inositol. They include mono- and polyphosphoric acid esters, with the exception of inositol hexaphosphate which is PHYTIC ACID.Phosphatidate Phosphatase: A phosphomonoesterase involved in the synthesis of triacylglycerols. It catalyzes the hydrolysis of phosphatidates with the formation of diacylglycerols and orthophosphate. EC Leucyl-Phenylalanine: A formylated tripeptide originally isolated from bacterial filtrates that is positively chemotactic to polymorphonuclear leucocytes, and causes them to release lysosomal enzymes and become metabolically activated.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.Group VI Phospholipases A2: A calcium-independent phospholipase A2 group that may play a role in membrane phospholipid remodeling and homeostasis by controling the levels of PHOSPHATIDYLCHOLINE in mammalian cell membranes.ral GTP-Binding Proteins: A family of ubiquitously expressed MONOMERIC GTP-BINDING PROTEINS that are involved in intracellular signal transduction. This enzyme was formerly listed as EC AcidsMolecular 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.Myristic Acid: A saturated 14-carbon fatty acid occurring in most animal and vegetable fats, particularly butterfat and coconut, palm, and nutmeg oils. It is used to synthesize flavor and as an ingredient in soaps and cosmetics. (From Dorland, 28th ed)Neomycin: Antibiotic complex produced by Streptomyces fradiae. It is composed of neomycins A, B, and C. It acts by inhibiting translation during protein synthesis.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.Oleic Acid: An unsaturated fatty acid that is the most widely distributed and abundant fatty acid in nature. It is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent. (Stedman, 26th ed)Myristic Acids: 14-carbon saturated monocarboxylic acids.Quinacrine: An acridine derivative formerly widely used as an antimalarial but superseded by chloroquine in recent years. It has also been used as an anthelmintic and in the treatment of giardiasis and malignant effusions. It is used in cell biological experiments as an inhibitor of phospholipase A2.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Diacylglycerol Kinase: An enzyme of the transferase class that uses ATP to catalyze the phosphorylation of diacylglycerol to a phosphatidate. EC Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Phosphatidylinositol Phosphates: Phosphatidylinositols in which one or more alcohol group of the inositol has been substituted with a phosphate group.Sphingosine: An amino alcohol with a long unsaturated hydrocarbon chain. Sphingosine and its derivative sphinganine are the major bases of the sphingolipids in mammals. (Dorland, 28th ed)Glycosylphosphatidylinositols: Compounds containing carbohydrate or glycosyl groups linked to phosphatidylinositols. They anchor GPI-LINKED PROTEINS or polysaccharides to cell membranes.Inositol 1,4,5-Trisphosphate: Intracellular messenger formed by the action of phospholipase C on phosphatidylinositol 4,5-bisphosphate, which is one of the phospholipids that make up the cell membrane. Inositol 1,4,5-trisphosphate is released into the cytoplasm where it releases calcium ions from internal stores within the cell's endoplasmic reticulum. These calcium ions stimulate the activity of B kinase or calmodulin.rhoA GTP-Binding Protein: A RHO GTP-BINDING PROTEIN involved in regulating signal transduction pathways that control assembly of focal adhesions and actin stress fibers. This enzyme was formerly listed as EC Compounds: Cyclic hydrocarbons that contain multiple rings and share one or more atoms.Phospholipases A2, Cytosolic: A subcategory of phospholipases A2 that occur in the CYTOSOL.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).)Group IB Phospholipases A2: A subclass of group I phospholipases A2 that includes enzymes isolated from PANCREATIC JUICE. Members of this group have specificity for PHOSPHOLIPASE A2 RECEPTORS.Neutrophils: Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.Detergents: Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.Chromatography, Thin Layer: Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Membrane Lipids: Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.Alkaloids: Organic nitrogenous bases. Many alkaloids of medical importance occur in the animal and vegetable kingdoms, and some have been synthesized. (Grant & Hackh's Chemical Dictionary, 5th ed)Pertussis Toxin: One of the virulence factors produced by BORDETELLA PERTUSSIS. It is a multimeric protein composed of five subunits S1 - S5. S1 contains mono ADPribose transferase activity.Virulence Factors, Bordetella: A set of BACTERIAL ADHESINS and TOXINS, BIOLOGICAL produced by BORDETELLA organisms that determine the pathogenesis of BORDETELLA INFECTIONS, such as WHOOPING COUGH. They include filamentous hemagglutinin; FIMBRIAE PROTEINS; pertactin; PERTUSSIS TOXIN; ADENYLATE CYCLASE TOXIN; dermonecrotic toxin; tracheal cytotoxin; Bordetella LIPOPOLYSACCHARIDES; and tracheal colonization factor.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Calcimycin: An ionophorous, polyether antibiotic from Streptomyces chartreusensis. It binds and transports CALCIUM and other divalent cations across membranes and uncouples oxidative phosphorylation while inhibiting ATPase of rat liver mitochondria. The substance is used mostly as a biochemical tool to study the role of divalent cations in various biological systems.Sphingomyelin Phosphodiesterase: An enzyme that catalyzes the hydrolysis of sphingomyelin to ceramide (N-acylsphingosine) plus choline phosphate. A defect in this enzyme leads to NIEMANN-PICK DISEASE. EC Disorders: Disturbances in mental processes related to learning, thinking, reasoning, and judgment.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.HL-60 Cells: A promyelocytic cell line derived from a patient with ACUTE PROMYELOCYTIC LEUKEMIA. HL-60 cells lack specific markers for LYMPHOID CELLS but express surface receptors for FC FRAGMENTS and COMPLEMENT SYSTEM PROTEINS. They also exhibit phagocytic activity and responsiveness to chemotactic stimuli. (From Hay et al., American Type Culture Collection, 7th ed, pp127-8)Pyrones: Keto-pyrans.Wasp Venoms: Venoms produced by the wasp (Vespid) family of stinging insects, including hornets; the venoms contain enzymes, biogenic amines, histamine releasing factors, kinins, toxic polypeptides, etc., and are similar to bee venoms.1-Alkyl-2-acetylglycerophosphocholine Esterase: A lipoprotein-associated PHOSPHOLIPASE A2 which modulates the action of PLATELET ACTIVATING FACTOR by hydrolyzing the SN-2 ester bond to yield the biologically inactive lyso-platelet-activating factor. It has specificity for phospholipid substrates with short-chain residues at the SN-2 position, but inactive against long-chain phospholipids. Deficiency in this enzyme is associated with many diseases including ASTHMA, and HYPERCHOLESTEROLEMIA.Resuscitation Orders: Instructions issued by a physician pertaining to the institution, continuation, or withdrawal of life support measures. The concept includes policies, laws, statutes, decisions, guidelines, and discussions that may affect the issuance of such orders.Propranolol: A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.Group X Phospholipases A2: A secreted phospholipase A2 subtype that contains a interfacial-binding region with specificity for PHOSPHATIDYLCHOLINE. This enzyme group may play a role in eliciting ARACHIDONIC ACID release from intact cellular membranes and from LOW DENSITY LIPOPROTEINS. Members of this group bind specifically to PHOSPHOLIPASE A2 RECEPTORS.Receptors, Muscarinic: One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.Ceramides: Members of the class of neutral glycosphingolipids. They are the basic units of SPHINGOLIPIDS. They are sphingoids attached via their amino groups to a long chain fatty acyl group. They abnormally accumulate in FABRY DISEASE.Staurosporine: An indolocarbazole that is a potent PROTEIN KINASE C inhibitor which enhances cAMP-mediated responses in human neuroblastoma cells. (Biochem Biophys Res Commun 1995;214(3):1114-20)Indoles: Benzopyrroles with the nitrogen at the number one carbon adjacent to the benzyl portion, in contrast to ISOINDOLES which have the nitrogen away from the six-membered ring.Phosphotransferases (Alcohol Group Acceptor): A group of enzymes that transfers a phosphate group onto an alcohol group acceptor. EC 2.7.1.Aluminum Compounds: Inorganic compounds that contain aluminum as an integral part of the molecule.Group V Phospholipases A2: A subcategory of secreted phospholipases A2 that contains both a negatively charged carboxy-terminal segment and interfacial-binding region specific for PHOSPHATIDYL CHOLINE-containing membranes. This enzyme group may play a role in the release of ARACHIDONIC ACID from phospholipid membranes.Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Ethanol: A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.Guanosine Triphosphate: Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.Crotalid Venoms: Venoms from snakes of the subfamily Crotalinae or pit vipers, found mostly in the Americas. They include the rattlesnake, cottonmouth, fer-de-lance, bushmaster, and American copperhead. Their venoms contain nontoxic proteins, cardio-, hemo-, cyto-, and neurotoxins, and many enzymes, especially phospholipases A. Many of the toxins have been characterized.Phosphorylcholine: Calcium and magnesium salts used therapeutically in hepatobiliary dysfunction.Carbachol: A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.Phosphoglycerate Mutase: An enzyme that catalyzes the conversion of 2-phospho-D-glycerate to 3-phospho-D-glycerate. EC Joint: The articulation between the articular surface of the PATELLA and the patellar surface of the FEMUR.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.Protein-Tyrosine Kinases: Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.Glycerides: GLYCEROL esterified with FATTY ACIDS.Platelet Activating Factor: A phospholipid derivative formed by PLATELETS; BASOPHILS; NEUTROPHILS; MONOCYTES; and MACROPHAGES. It is a potent platelet aggregating agent and inducer of systemic anaphylactic symptoms, including HYPOTENSION; THROMBOCYTOPENIA; NEUTROPENIA; and BRONCHOCONSTRICTION.Bee Venoms: Venoms obtained from Apis mellifera (honey bee) and related species. They contain various enzymes, polypeptide toxins, and other substances, some of which are allergenic or immunogenic or both. These venoms were formerly used in rheumatism to stimulate the pituitary-adrenal system.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.Sodium Fluoride: A source of inorganic fluoride which is used topically to prevent dental caries.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.Ethanolamine: A viscous, hygroscopic amino alcohol with an ammoniacal odor. It is widely distributed in biological tissue and is a component of lecithin. It is used as a surfactant, fluorimetric reagent, and to remove CO2 and H2S from natural gas and other gases.Ionomycin: A divalent calcium ionophore that is widely used as a tool to investigate the role of intracellular calcium in cellular processes.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Oleic Acids: A group of fatty acids that contain 18 carbon atoms and a double bond at the omega 9 carbon.Second Messenger Systems: Systems in which an intracellular signal is generated in response to an intercellular primary messenger such as a hormone or neurotransmitter. They are intermediate signals in cellular processes such as metabolism, secretion, contraction, phototransduction, and cell growth. Examples of second messenger systems are the adenyl cyclase-cyclic AMP system, the phosphatidylinositol diphosphate-inositol triphosphate system, and the cyclic GMP system.Time Factors: Elements of limited time intervals, contributing to particular results or situations.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.Heterotrimeric GTP-Binding Proteins: GTP-BINDING PROTEINS that contain three non-identical subunits. They are found associated with members of the seven transmembrane domain superfamily of G-PROTEIN-COUPLED RECEPTORS. Upon activation the GTP-BINDING PROTEIN ALPHA SUBUNIT of the complex dissociates leaving a dimer of a GTP-BINDING PROTEIN BETA SUBUNIT bound to a GTP-BINDING PROTEIN GAMMA SUBUNIT.