Protein Kinase Inhibitors: Agents that inhibit PROTEIN KINASES.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.Protein Kinases: A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.Cyclic AMP-Dependent Protein Kinases: A group of enzymes that are dependent on CYCLIC AMP and catalyze the phosphorylation of SERINE or THREONINE residues on proteins. Included under this category are two cyclic-AMP-dependent protein kinase subtypes, each of which is defined by its subunit composition.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)Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine: A specific protein kinase C inhibitor, which inhibits superoxide release from human neutrophils (PMN) stimulated with phorbol myristate acetate or synthetic diacylglycerol.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.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.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)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).p38 Mitogen-Activated Protein Kinases: A mitogen-activated protein kinase subfamily that regulates a variety of cellular processes including CELL GROWTH PROCESSES; CELL DIFFERENTIATION; APOPTOSIS; and cellular responses to INFLAMMATION. The P38 MAP kinases are regulated by CYTOKINE RECEPTORS and can be activated in response to bacterial pathogens.Isoquinolines: A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)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.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.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)MAP Kinase Signaling System: An intracellular signaling system involving the MAP kinase cascades (three-membered protein kinase cascades). Various upstream activators, which act in response to extracellular stimuli, trigger the cascades by activating the first member of a cascade, MAP KINASE KINASE KINASES; (MAPKKKs). Activated MAPKKKs phosphorylate MITOGEN-ACTIVATED PROTEIN KINASE KINASES which in turn phosphorylate the MITOGEN-ACTIVATED PROTEIN KINASES; (MAPKs). The MAPKs then act on various downstream targets to affect gene expression. In mammals, there are several distinct MAP kinase pathways including the ERK (extracellular signal-regulated kinase) pathway, the SAPK/JNK (stress-activated protein kinase/c-jun kinase) pathway, and the p38 kinase pathway. There is some sharing of components among the pathways depending on which stimulus originates activation of the cascade.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.Indole Alkaloids: Group of alkaloids containing a benzylpyrrole group (derived from TRYPTOPHAN)Protein-Tyrosine Kinases: Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.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.Carbazoles: Benzo-indoles similar to CARBOLINES which are pyrido-indoles. In plants, carbazoles are derived from indole and form some of the INDOLE ALKALOIDS.Mitogen-Activated Protein Kinase Kinases: A serine-threonine protein kinase family whose members are components in protein kinase cascades activated by diverse stimuli. These MAPK kinases phosphorylate MITOGEN-ACTIVATED PROTEIN KINASES and are themselves phosphorylated by MAP KINASE KINASE KINASES. JNK kinases (also known as SAPK kinases) are a subfamily.Mitogen-Activated Protein Kinase 3: A 44-kDa extracellular signal-regulated MAP kinase that may play a role the initiation and regulation of MEIOSIS; MITOSIS; and postmitotic functions in differentiated cells. It phosphorylates a number of TRANSCRIPTION FACTORS; and MICROTUBULE-ASSOCIATED PROTEINS.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.Tetradecanoylphorbol Acetate: A phorbol ester found in CROTON OIL with very effective tumor promoting activity. It stimulates the synthesis of both DNA and RNA.JNK Mitogen-Activated Protein Kinases: A subgroup of mitogen-activated protein kinases that activate TRANSCRIPTION FACTOR AP-1 via the phosphorylation of C-JUN PROTEINS. They are components of intracellular signaling pathways that regulate CELL PROLIFERATION; APOPTOSIS; and CELL DIFFERENTIATION.Cyclic GMP-Dependent Protein Kinases: A group of cyclic GMP-dependent enzymes that catalyze the phosphorylation of SERINE or THREONINE residues of proteins.Cyclic AMP: An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.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.PiperazinesIndoles: 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.Protein Kinase C-delta: A ubiquitously expressed protein kinase that is involved in a variety of cellular SIGNAL PATHWAYS. Its activity is regulated by a variety of signaling protein tyrosine kinase.Cell Line: Established cell cultures that have the potential to propagate indefinitely.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.Pyridines: Compounds with a six membered aromatic ring containing NITROGEN. The saturated version is PIPERIDINES.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.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.Kinetics: The rate dynamics in chemical or physical systems.AMP-Activated Protein Kinases: Intracellular signaling protein kinases that play a signaling role in the regulation of cellular energy metabolism. Their activity largely depends upon the concentration of cellular AMP which is increased under conditions of low energy or metabolic stress. AMP-activated protein kinases modify enzymes involved in LIPID METABOLISM, which in turn provide substrates needed to convert AMP into ATP.Pyrimidines: A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They include several nucleic acid constituents (CYTOSINE; THYMINE; and URACIL) and form the basic structure of the barbiturates.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.Cyclin-Dependent Kinases: Protein kinases that control cell cycle progression in all eukaryotes and require physical association with CYCLINS to achieve full enzymatic activity. Cyclin-dependent kinases are regulated by phosphorylation and dephosphorylation events.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.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.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.Flavonoids: A group of phenyl benzopyrans named for having structures like FLAVONES.Protein Kinase C-epsilon: A protein kinase C subtype that was originally characterized as a CALCIUM-independent, serine-threonine kinase that is activated by PHORBOL ESTERS and DIACYLGLYCEROLS. It is targeted to specific cellular compartments in response to extracellular signals that activate G-PROTEIN-COUPLED RECEPTORS; TYROSINE KINASE RECEPTORS; and intracellular protein tyrosine kinase.CDC2 Protein Kinase: Phosphoprotein with protein kinase activity that functions in the G2/M phase transition of the CELL CYCLE. It is the catalytic subunit of the MATURATION-PROMOTING FACTOR and complexes with both CYCLIN A and CYCLIN B in mammalian cells. The maximal activity of cyclin-dependent kinase 1 is achieved when it is fully dephosphorylated.Protein Kinase C beta: PKC beta encodes two proteins (PKCB1 and PKCBII) generated by alternative splicing of C-terminal exons. It is widely distributed with wide-ranging roles in processes such as B-cell receptor regulation, oxidative stress-induced apoptosis, androgen receptor-dependent transcriptional regulation, insulin signaling, and endothelial cell proliferation.MaleimidesCasein Kinase II: A ubiquitous casein kinase that is comprised of two distinct catalytic subunits and dimeric regulatory subunit. Casein kinase II has been shown to phosphorylate a large number of substrates, many of which are proteins involved in the regulation of gene expression.Imidazoles: Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Cyclin-Dependent Kinase Inhibitor p27: A cyclin-dependent kinase inhibitor that coordinates the activation of CYCLIN and CYCLIN-DEPENDENT KINASES during the CELL CYCLE. It interacts with active CYCLIN D complexed to CYCLIN-DEPENDENT KINASE 4 in proliferating cells, while in arrested cells it binds and inhibits CYCLIN E complexed to CYCLIN-DEPENDENT KINASE 2.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.PhosphoproteinsTransfection: 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.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.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.Apoptosis: One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.Proto-Oncogene Proteins c-akt: A protein-serine-threonine kinase that is activated by PHOSPHORYLATION in response to GROWTH FACTORS or INSULIN. It plays a major role in cell metabolism, growth, and survival as a core component of SIGNAL TRANSDUCTION. Three isoforms have been described in mammalian cells.Calcium-Calmodulin-Dependent Protein Kinase Type 2: A multifunctional calcium-calmodulin-dependent protein kinase subtype that occurs as an oligomeric protein comprised of twelve subunits. It differs from other enzyme subtypes in that it lacks a phosphorylatable activation domain that can respond to CALCIUM-CALMODULIN-DEPENDENT PROTEIN KINASE KINASE.Cyclin-Dependent Kinase Inhibitor p21: A cyclin-dependent kinase inhibitor that mediates TUMOR SUPPRESSOR PROTEIN P53-dependent CELL CYCLE arrest. p21 interacts with a range of CYCLIN-DEPENDENT KINASES and associates with PROLIFERATING CELL NUCLEAR ANTIGEN and CASPASE 3.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.Sulfonamides: A group of compounds that contain the structure SO2NH2.Extracellular Signal-Regulated MAP Kinases: A mitogen-activated protein kinase subfamily that is widely expressed and plays a role in regulation of MEIOSIS; MITOSIS; and post mitotic functions in differentiated cells. The extracellular signal regulated MAP kinases are regulated by a broad variety of CELL SURFACE RECEPTORS and can be activated by certain CARCINOGENS.ChromonesAndrostadienes: Derivatives of the steroid androstane having two double bonds at any site in any of the rings.Cell Line, Tumor: A cell line derived from cultured tumor cells.MAP Kinase Kinase 1: An abundant 43-kDa mitogen-activated protein kinase kinase subtype with specificity for MITOGEN-ACTIVATED PROTEIN KINASE 1 and MITOGEN-ACTIVATED PROTEIN KINASE 3.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.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.Okadaic Acid: A specific inhibitor of phosphoserine/threonine protein phosphatase 1 and 2a. It is also a potent tumor promoter. (Thromb Res 1992;67(4):345-54 & Cancer Res 1993;53(2):239-41)Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Benzamides: BENZOIC ACID amides.Phorbol 12,13-Dibutyrate: A phorbol ester found in CROTON OIL which, in addition to being a potent skin tumor promoter, is also an effective activator of calcium-activated, phospholipid-dependent protein kinase (protein kinase C). Due to its activation of this enzyme, phorbol 12,13-dibutyrate profoundly affects many different biological systems.Phorbol Esters: Tumor-promoting compounds obtained from CROTON OIL (Croton tiglium). Some of these are used in cell biological experiments as activators of protein kinase C.MorpholinesMAP Kinase Kinase Kinases: Mitogen-activated protein kinase kinase kinases (MAPKKKs) are serine-threonine protein kinases that initiate protein kinase signaling cascades. They phosphorylate MITOGEN-ACTIVATED PROTEIN KINASE KINASES; (MAPKKs) which in turn phosphorylate MITOGEN-ACTIVATED PROTEIN KINASES; (MAPKs).Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.Casein Kinases: A group of protein-serine-threonine kinases that was originally identified as being responsible for the PHOSPHORYLATION of CASEINS. They are ubiquitous enzymes that have a preference for acidic proteins. Casein kinases play a role in SIGNAL TRANSDUCTION by phosphorylating a variety of regulatory cytoplasmic and regulatory nuclear proteins.rho-Associated Kinases: A group of intracellular-signaling serine threonine kinases that bind to RHO GTP-BINDING PROTEINS. They were originally found to mediate the effects of rhoA GTP-BINDING PROTEIN on the formation of STRESS FIBERS and FOCAL ADHESIONS. Rho-associated kinases have specificity for a variety of substrates including MYOSIN-LIGHT-CHAIN PHOSPHATASE and LIM KINASES.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Recombinant Proteins: Proteins prepared by recombinant DNA technology.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.Antineoplastic Agents: Substances that inhibit or prevent the proliferation of NEOPLASMS.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Adenosine Triphosphate: An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.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)Diglyceridesp21-Activated Kinases: A family of serine-threonine kinases that bind to and are activated by MONOMERIC GTP-BINDING PROTEINS such as RAC GTP-BINDING PROTEINS and CDC42 GTP-BINDING PROTEIN. They are intracellular signaling kinases that play a role the regulation of cytoskeletal organization.Cell Cycle: The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.Cyclic AMP-Dependent Protein Kinase Type II: A cyclic AMP-dependent protein kinase subtype primarily found in particulate subcellular fractions. They are tetrameric proteins that contain two catalytic subunits and two type II-specific regulatory subunits.Tyrosine: A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.eIF-2 Kinase: A dsRNA-activated cAMP-independent protein serine/threonine kinase that is induced by interferon. In the presence of dsRNA and ATP, the kinase autophosphorylates on several serine and threonine residues. The phosphorylated enzyme catalyzes the phosphorylation of the alpha subunit of EUKARYOTIC INITIATION FACTOR-2, leading to the inhibition of protein synthesis.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Butadienes: Four carbon unsaturated hydrocarbons containing two double bonds.Nitriles: Organic compounds containing the -CN radical. The concept is distinguished from CYANIDES, which denotes inorganic salts of HYDROGEN CYANIDE.Ribosomal Protein S6 Kinases: A family of protein serine/threonine kinases which act as intracellular signalling intermediates. Ribosomal protein S6 kinases are activated through phosphorylation in response to a variety of HORMONES and INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS. Phosphorylation of RIBOSOMAL PROTEIN S6 by enzymes in this class results in increased expression of 5' top MRNAs. Although specific for RIBOSOMAL PROTEIN S6 members of this class of kinases can act on a number of substrates within the cell. The immunosuppressant SIROLIMUS inhibits the activation of ribosomal protein S6 kinases.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Pyrroles: Azoles of one NITROGEN and two double bonds that have aromatic chemical properties.Ethers, Cyclic: Compounds of the general formula R-O-R arranged in a ring or crown formation.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.Receptor Protein-Tyrosine Kinases: A class of cellular receptors that have an intrinsic PROTEIN-TYROSINE KINASE activity.MAP Kinase Kinase 4: A mitogen-activated protein kinase kinase with specificity for JNK MITOGEN-ACTIVATED PROTEIN KINASES; P38 MITOGEN-ACTIVATED PROTEIN KINASES and the RETINOID X RECEPTORS. It takes part in a SIGNAL TRANSDUCTION pathway that is activated in response to cellular stress.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.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.Down-Regulation: A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Phosphotransferases (Alcohol Group Acceptor): A group of enzymes that transfers a phosphate group onto an alcohol group acceptor. EC 2.7.1.Naphthalenes: Two-ring crystalline hydrocarbons isolated from coal tar. They are used as intermediates in chemical synthesis, as insect repellents, fungicides, lubricants, preservatives, and, formerly, as topical antiseptics.Colforsin: Potent activator of the adenylate cyclase system and the biosynthesis of cyclic AMP. From the plant COLEUS FORSKOHLII. Has antihypertensive, positive inotropic, platelet aggregation inhibitory, and smooth muscle relaxant activities; also lowers intraocular pressure and promotes release of hormones from the pituitary gland.Protamine Kinase: An aspect of protein kinase (EC 2.7.1.37) in which serine residues in protamines and histones are phosphorylated in the presence of ATP.Cell Cycle Proteins: Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Cell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.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.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.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.QuinazolinesGene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Cyclic GMP: Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed)HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Benzophenanthridines: Compounds of four rings containing a nitrogen. They are biosynthesized from reticuline via rearrangement of scoulerine. They are similar to BENZYLISOQUINOLINES. Members include chelerythrine and sanguinarine.Aurora Kinases: A family of highly conserved serine-threonine kinases that are involved in the regulation of MITOSIS. They are involved in many aspects of cell division, including centrosome duplication, SPINDLE APPARATUS formation, chromosome alignment, attachment to the spindle, checkpoint activation, and CYTOKINESIS.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.Cell Survival: The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.Mitogen-Activated Protein Kinase 14: A 38-kDa mitogen-activated protein kinase that is abundantly expressed in a broad variety of cell types. It is involved in the regulation of cellular stress responses as well as the control of proliferation and survival of many cell types. The kinase activity of the enzyme is inhibited by the pyridinyl-imidazole compound SB 203580.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.Glycogen Synthase Kinase 3: A glycogen synthase kinase that was originally described as a key enzyme involved in glycogen metabolism. It regulates a diverse array of functions such as CELL DIVISION, microtubule function and APOPTOSIS.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.PhenanthridinesModels, 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.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Myosin-Light-Chain Kinase: An enzyme that phosphorylates myosin light chains in the presence of ATP to yield myosin-light chain phosphate and ADP, and requires calcium and CALMODULIN. The 20-kDa light chain is phosphorylated more rapidly than any other acceptor, but light chains from other myosins and myosin itself can act as acceptors. The enzyme plays a central role in the regulation of smooth muscle contraction.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Cyclins: A large family of regulatory proteins that function as accessory subunits to a variety of CYCLIN-DEPENDENT KINASES. They generally function as ENZYME ACTIVATORS that drive the CELL CYCLE through transitions between phases. A subset of cyclins may also function as transcriptional regulators.Tyrphostins: A family of synthetic protein tyrosine kinase inhibitors. They selectively inhibit receptor autophosphorylation and are used to study receptor function.DNA-Activated Protein Kinase: A serine-threonine protein kinase that, when activated by DNA, phosphorylates several DNA-binding protein substrates including the TUMOR SUPPRESSOR PROTEIN P53 and a variety of TRANSCRIPTION FACTORS.2-Aminopurine: A purine that is an isomer of ADENINE (6-aminopurine).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.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Pyrazoles: Azoles of two nitrogens at the 1,2 positions, next to each other, in contrast with IMIDAZOLES in which they are at the 1,3 positions.8-Bromo Cyclic Adenosine Monophosphate: A long-acting derivative of cyclic AMP. It is an activator of cyclic AMP-dependent protein kinase, but resistant to degradation by cyclic AMP phosphodiesterase.CDC2-CDC28 Kinases: A family of cell cycle-dependent kinases that are related in structure to CDC28 PROTEIN KINASE; S CEREVISIAE; and the CDC2 PROTEIN KINASE found in mammalian species.3-Phosphoinositide-Dependent Protein Kinases: Highly conserved protein-serine threonine kinases that phosphorylate and activate a group of AGC protein kinases, especially in response to the production of the SECOND MESSENGERS, phosphatidylinositol 3,4,-biphosphate (PtdIns(3,4)P2) and phosphatidylinositol 3,4,5-triphosphate (PtdIns(3,4,5)P3).Creatine Kinase: A transferase that catalyzes formation of PHOSPHOCREATINE from ATP + CREATINE. The reaction stores ATP energy as phosphocreatine. Three cytoplasmic ISOENZYMES have been identified in human tissues: the MM type from SKELETAL MUSCLE, the MB type from myocardial tissue and the BB type from nervous tissue as well as a mitochondrial isoenzyme. Macro-creatine kinase refers to creatine kinase complexed with other serum proteins.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.Up-Regulation: A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.ThiazolesCell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Thionucleotides: Nucleotides in which the base moiety is substituted with one or more sulfur atoms.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.Threonine: An essential amino acid occurring naturally in the L-form, which is the active form. It is found in eggs, milk, gelatin, and other proteins.Pyruvate Kinase: ATP:pyruvate 2-O-phosphotransferase. A phosphotransferase that catalyzes reversibly the phosphorylation of pyruvate to phosphoenolpyruvate in the presence of ATP. It has four isozymes (L, R, M1, and M2). Deficiency of the enzyme results in hemolytic anemia. EC 2.7.1.40.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.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.Nuclear Proteins: Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.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.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Ribosomal Protein S6 Kinases, 90-kDa: A family of ribosomal protein S6 kinases that are structurally distinguished from RIBOSOMAL PROTEIN S6 KINASES, 70-KDA by their apparent molecular size and the fact they contain two functional kinase domains. Although considered RIBOSOMAL PROTEIN S6 KINASES, members of this family are activated via the MAP KINASE SIGNALING SYSTEM and have been shown to act on a diverse array of substrates that are involved in cellular regulation such as RIBOSOMAL PROTEIN S6 and CAMP RESPONSE ELEMENT-BINDING PROTEIN.Drug Synergism: The action of a drug in promoting or enhancing the effectiveness of another drug.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.Diacylglycerol Kinase: An enzyme of the transferase class that uses ATP to catalyze the phosphorylation of diacylglycerol to a phosphatidate. EC 2.7.1.107.Mitogen-Activated Protein Kinase 8: A c-jun amino-terminal kinase that is activated by environmental stress and pro-inflammatory cytokines. Several isoforms of the protein with molecular sizes of 43 and 48 KD exist due to multiple ALTERNATIVE SPLICING.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.NF-kappa B: Ubiquitous, inducible, nuclear transcriptional activator that binds to enhancer elements in many different cell types and is activated by pathogenic stimuli. The NF-kappa B complex is a heterodimer composed of two DNA-binding subunits: NF-kappa B1 and relA.Phosphoserine: The phosphoric acid ester of serine.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.I-kappa B Kinase: A protein serine-threonine kinase that catalyzes the PHOSPHORYLATION of I KAPPA B PROTEINS. This enzyme also activates the transcription factor NF-KAPPA B and is composed of alpha and beta catalytic subunits, which are protein kinases and gamma, a regulatory subunit.MAP Kinase Kinase 2: A 44 kDa mitogen-activated protein kinase kinase with specificity for MITOGEN-ACTIVATED PROTEIN KINASE 1 and MITOGEN-ACTIVATED PROTEIN KINASE 3.MAP Kinase Kinase Kinase 1: A 195-kDa MAP kinase kinase kinase with broad specificity for MAP KINASE KINASES. It is found localized in the CYTOSKELETON and can activate a variety of MAP kinase-dependent pathways.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Molecular Weight: The sum of the weight of all the atoms in a molecule.Calmodulin: A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.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.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.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.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.1-Phosphatidylinositol 4-Kinase: An enzyme that catalyzes the conversion of phosphatidylinositol (PHOSPHATIDYLINOSITOLS) to phosphatidylinositol 4-phosphate, the first committed step in the biosynthesis of phosphatidylinositol 4,5-bisphosphate.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.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.RNA, Small Interfering: Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.Enzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Thymidine Kinase: An enzyme that catalyzes the conversion of ATP and thymidine to ADP and thymidine 5'-phosphate. Deoxyuridine can also act as an acceptor and dGTP as a donor. (From Enzyme Nomenclature, 1992) EC 2.7.1.21.TOR Serine-Threonine Kinases: A serine threonine kinase that controls a wide range of growth-related cellular processes. The protein is referred to as the target of RAPAMYCIN due to the discovery that SIROLIMUS (commonly known as rapamycin) forms an inhibitory complex with TACROLIMUS BINDING PROTEIN 1A that blocks the action of its enzymatic activity.Cyclin-Dependent Kinase Inhibitor p57: A potent inhibitor of CYCLIN-DEPENDENT KINASES in G1 PHASE and S PHASE. In humans, aberrant expression of p57 is associated with various NEOPLASMS as well as with BECKWITH-WIEDEMANN SYNDROME.Oxazoles: Five-membered heterocyclic ring structures containing an oxygen in the 1-position and a nitrogen in the 3-position, in distinction from ISOXAZOLES where they are at the 1,2 positions.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.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Cyclic AMP Response Element-Binding Protein: A protein that has been shown to function as a calcium-regulated transcription factor as well as a substrate for depolarization-activated CALCIUM-CALMODULIN-DEPENDENT PROTEIN KINASES. This protein functions to integrate both calcium and cAMP signals.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Cyclin-Dependent Kinase 2: A key regulator of CELL CYCLE progression. It partners with CYCLIN E to regulate entry into S PHASE and also interacts with CYCLIN A to phosphorylate RETINOBLASTOMA PROTEIN. Its activity is inhibited by CYCLIN-DEPENDENT KINASE INHIBITOR P27 and CYCLIN-DEPENDENT KINASE INHIBITOR P21.Mitosis: A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.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.Myocardium: The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.