Proto-Oncogene Proteins c-raf: A ubiquitously expressed raf kinase subclass that plays an important role in SIGNAL TRANSDUCTION. The c-raf Kinases are MAP kinase kinase kinases that have specificity for MAP KINASE KINASE 1 and MAP KINASE KINASE 2.Proto-Oncogene Proteins A-raf: A raf kinase subclass expressed primarily in non-neuronal tissues such as SKELETAL MUSCLE. The A-raf kinases are MAP kinase kinase kinases that have specificity for MAP KINASE KINASE 1.DNA, Concatenated: Head to tail array of covalently joined DNA sequences generated by concatenation. Concatenated DNA is attached end to end in contrast to CATENATED DNA which is attached loop to loop.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.Proto-Oncogenes: Normal cellular genes homologous to viral oncogenes. The products of proto-oncogenes are important regulators of biological processes and appear to be involved in the events that serve to maintain the ordered procession through the cell cycle. Proto-oncogenes have names of the form c-onc.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.Proto-Oncogene Proteins c-fes: Proto-oncogene proteins fes are protein-tyrosine kinases with a central SH2 DOMAIN. It has been implicated in SIGNAL TRANSDUCTION PATHWAYS for CELL DIFFERENTIATION of a variety of cell types including MYELOID PROGENITOR CELLS. Fes proto-oncogene proteins also bind TUBULIN and promote MICROTUBULE assembly.Proto-Oncogene Proteins c-myb: Cellular DNA-binding proteins encoded by the myb gene (GENES, MYB). They are expressed in a wide variety of cells including thymocytes and lymphocytes, and regulate cell differentiation. Overexpression of myb is associated with autoimmune diseases and malignancies.Proto-Oncogene Proteins c-myc: Cellular DNA-binding proteins encoded by the c-myc genes. They are normally involved in nucleic acid metabolism and in mediating the cellular response to growth factors. Elevated and deregulated (constitutive) expression of c-myc proteins can cause tumorigenesis.Proto-Oncogene Proteins c-maf: Maf proto-oncogene protein is the major cellular homolog of the V-MAF ONCOGENE PROTEIN. It was the first of the mammalian MAF TRANSCRIPTION FACTORS identified, and it is induced in activated T-LYMPHOCYTES and regulates GENETIC TRANSCRIPTION of INTERLEUKIN-4. c-maf is frequently translocated to an immunoglobulin locus in MULTIPLE MYELOMA.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).Proto-Oncogene Proteins c-bcl-6: A DNA-binding protein that represses GENETIC TRANSCRIPTION of target genes by recruiting HISTONE DEACETYLASES. Aberrant Blc-6 expression is associated with certain types of human B-CELL LYMPHOMA.Proto-Oncogene Proteins c-pim-1: Serine-threonine protein kinases that relay signals from CYTOKINE RECEPTORS and are involved in control of CELL GROWTH PROCESSES; CELL DIFFERENTIATION; and APOPTOSIS.Proto-Oncogene Proteins c-fos: Cellular DNA-binding proteins encoded by the c-fos genes (GENES, FOS). They are involved in growth-related transcriptional control. c-fos combines with c-jun (PROTO-ONCOGENE PROTEINS C-JUN) to form a c-fos/c-jun heterodimer (TRANSCRIPTION FACTOR AP-1) that binds to the TRE (TPA-responsive element) in promoters of certain genes.Proto-Oncogene Proteins c-vav: Proto-oncogene proteins that are guanine nucleotide exchange factors for RHO GTPASES. They also function as signal transducing adaptor proteins.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.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.Proto-Oncogene Proteins c-mos: Cellular proteins encoded by the c-mos genes (GENES, MOS). They function in the cell cycle to maintain MATURATION PROMOTING FACTOR in the active state and have protein-serine/threonine kinase activity. Oncogenic transformation can take place when c-mos proteins are expressed at the wrong time.Proto-Oncogene Proteins c-hck: Members of the src-family tyrosine kinase family that are strongly expressed in MYELOID CELLS and B-LYMPHOCYTES.Proto-Oncogene Protein c-ets-2: A ubiquitously expressed ets proto-oncogene protein that may play a role in regulation of CELL PROLIFERATION and CELL DIFFERENTIATION.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 Protein c-ets-1: An ets proto-oncogene expressed primarily in adult LYMPHOID TISSUE; BRAIN; and VASCULAR ENDOTHELIAL CELLS.Proto-Oncogene Proteins c-met: Cell surface protein-tyrosine kinase receptors for HEPATOCYTE GROWTH FACTOR. They consist of an extracellular alpha chain which is disulfide-linked to the transmembrane beta chain. The cytoplasmic portion contains the catalytic domain and sites critical for the regulation of kinase activity. Mutations of the gene for PROTO-ONCOGENE PROTEINS C-MET are associated with papillary renal carcinoma and other neoplasia.Proto-Oncogene Proteins p21(ras): Cellular proteins encoded by the H-ras, K-ras and N-ras genes. The proteins have GTPase activity and are involved in signal transduction as monomeric GTP-binding proteins. Elevated levels of p21 c-ras have been associated with neoplasia. This enzyme was formerly listed as EC 3.6.1.47.Proto-Oncogene Proteins c-kit: A protein-tyrosine kinase receptor that is specific for STEM CELL FACTOR. This interaction is crucial for the development of hematopoietic, gonadal, and pigment stem cells. Genetic mutations that disrupt the expression of PROTO-ONCOGENE PROTEINS C-KIT are associated with PIEBALDISM, while overexpression or constitutive activation of the c-kit protein-tyrosine kinase is associated with tumorigenesis.Proto-Oncogene Proteins c-rel: Cellular DNA-binding proteins encoded by the rel gene (GENES, REL). They are expressed predominately in hematopoietic cells and may play a role in lymphocyte differentiation. Rel frequently combines with other related proteins (NF-KAPPA B, I-kappa B, relA) to form heterodimers that regulate transcription. Rearrangement or overexpression of c-rel can cause tumorigenesis.Proto-Oncogene Proteins c-ets: A family of transcription factors that share a unique DNA-binding domain. The name derives from viral oncogene-derived protein oncogene protein v-ets of the AVIAN ERYTHROBLASTOSIS VIRUS.Proto-Oncogene Proteins B-raf: A raf kinase subclass found at high levels in neuronal tissue. The B-raf Kinases are MAP kinase kinase kinases that have specificity for MAP KINASE KINASE 1 and MAP KINASE KINASE 2.Multiple Endocrine Neoplasia Type 2a: A form of multiple endocrine neoplasia characterized by the presence of medullary carcinoma (CARCINOMA, MEDULLARY) of the THYROID GLAND, and usually with the co-occurrence of PHEOCHROMOCYTOMA, producing CALCITONIN and ADRENALINE, respectively. Less frequently, it can occur with hyperplasia or adenoma of the PARATHYROID GLANDS. This disease is due to gain-of-function mutations of the MEN2 gene on CHROMOSOME 10 (Locus: 10q11.2), also known as the RET proto-oncogene that encodes a RECEPTOR PROTEIN-TYROSINE KINASE. It is an autosomal dominant inherited disease.Proto-Oncogene Proteins c-jun: Cellular DNA-binding proteins encoded by the c-jun genes (GENES, JUN). They are involved in growth-related transcriptional control. There appear to be three distinct functions: dimerization (with c-fos), DNA-binding, and transcriptional activation. Oncogenic transformation can take place by constitutive expression of c-jun.Proto-Oncogene Protein c-fli-1: A member of the c-ets family of transcription factors that is preferentially expressed in cells of hematopoietic lineages and vascular endothelial cells. It was originally identified as a protein that provides a retroviral integration site for integration of FRIEND MURINE LEUKEMIA VIRUS.Carcinoma, Medullary: A carcinoma composed mainly of epithelial elements with little or no stroma. Medullary carcinomas of the breast constitute 5%-7% of all mammary carcinomas; medullary carcinomas of the thyroid comprise 3%-10% of all thyroid malignancies. (From Dorland, 27th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1141; Segen, Dictionary of Modern Medicine, 1992)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.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.Genes, myc: Family of retrovirus-associated DNA sequences (myc) originally isolated from an avian myelocytomatosis virus. The proto-oncogene myc (c-myc) codes for a nuclear protein which is involved in nucleic acid metabolism and in mediating the cellular response to growth factors. Truncation of the first exon, which appears to regulate c-myc expression, is crucial for tumorigenicity. The human c-myc gene is located at 8q24 on the long arm of chromosome 8.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.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.Genes, ras: Family of retrovirus-associated DNA sequences (ras) originally isolated from Harvey (H-ras, Ha-ras, rasH) and Kirsten (K-ras, Ki-ras, rasK) murine sarcoma viruses. Ras genes are widely conserved among animal species and sequences corresponding to both H-ras and K-ras genes have been detected in human, avian, murine, and non-vertebrate genomes. The closely related N-ras gene has been detected in human neuroblastoma and sarcoma cell lines. All genes of the family have a similar exon-intron structure and each encodes a p21 protein.Protein-Tyrosine Kinases: Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.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.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.Proto-Oncogene Proteins c-fyn: Src-family kinases that associate with T-CELL ANTIGEN RECEPTOR and phosphorylate a wide variety of intracellular signaling molecules.Receptor Protein-Tyrosine Kinases: A class of cellular receptors that have an intrinsic PROTEIN-TYROSINE KINASE activity.Multiple Endocrine Neoplasia Type 2b: Similar to MEN2A, it is also caused by mutations of the MEN2 gene, also known as the RET proto-oncogene. Its clinical symptoms include medullary carcinoma (CARCINOMA, MEDULLARY) of THYROID GLAND and PHEOCHROMOCYTOMA of ADRENAL MEDULLA (50%). Unlike MEN2a, MEN2b does not involve PARATHYROID NEOPLASMS. It can be distinguished from MEN2A by its neural abnormalities such as mucosal NEUROMAS on EYELIDS; LIP; and TONGUE, and ganglioneuromatosis of GASTROINTESTINAL TRACT leading to MEGACOLON. It is an autosomal dominant inherited disease.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.Proto-Oncogene Proteins c-bcl-2: Membrane proteins encoded by the BCL-2 GENES and serving as potent inhibitors of cell death by APOPTOSIS. The proteins are found on mitochondrial, microsomal, and NUCLEAR MEMBRANE sites within many cell types. Overexpression of bcl-2 proteins, due to a translocation of the gene, is associated with follicular lymphoma.Oncogenes: Genes whose gain-of-function alterations lead to NEOPLASTIC CELL TRANSFORMATION. They include, for example, genes for activators or stimulators of CELL PROLIFERATION such as growth factors, growth factor receptors, protein kinases, signal transducers, nuclear phosphoproteins, and transcription factors. A prefix of "v-" before oncogene symbols indicates oncogenes captured and transmitted by RETROVIRUSES; the prefix "c-" before the gene symbol of an oncogene indicates it is the cellular homolog (PROTO-ONCOGENES) of a v-oncogene.Cell Line: Established cell cultures that have the potential to propagate indefinitely.ras Proteins: Small, monomeric GTP-binding proteins encoded by ras genes (GENES, RAS). The protooncogene-derived protein, PROTO-ONCOGENE PROTEIN P21(RAS), plays a role in normal cellular growth, differentiation and development. The oncogene-derived protein (ONCOGENE PROTEIN P21(RAS)) can play a role in aberrant cellular regulation during neoplastic cell transformation (CELL TRANSFORMATION, NEOPLASTIC). This enzyme was formerly listed as EC 3.6.1.47.Genes, fos: Retrovirus-associated DNA sequences (fos) originally isolated from the Finkel-Biskis-Jinkins (FBJ-MSV) and Finkel-Biskis-Reilly (FBR-MSV) murine sarcoma viruses. The proto-oncogene protein c-fos codes for a nuclear protein which is involved in growth-related transcriptional control. The insertion of c-fos into FBJ-MSV or FBR-MSV induces osteogenic sarcomas in mice. The human c-fos gene is located at 14q21-31 on the long arm of chromosome 14.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.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.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.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.Hirschsprung Disease: Congenital MEGACOLON resulting from the absence of ganglion cells (aganglionosis) in a distal segment of the LARGE INTESTINE. The aganglionic segment is permanently contracted thus causing dilatation proximal to it. In most cases, the aganglionic segment is within the RECTUM and SIGMOID COLON.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.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.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.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.Gene Expression Regulation, Neoplastic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in neoplastic tissue.Thyroid Neoplasms: Tumors or cancer of the THYROID GLAND.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.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.Proto-Oncogene Proteins c-mdm2: An E3 UBIQUITIN LIGASE that interacts with and inhibits TUMOR SUPPRESSOR PROTEIN P53. Its ability to ubiquitinate p53 is regulated by TUMOR SUPPRESSOR PROTEIN P14ARF.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.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.Oncogene Proteins: Proteins coded by oncogenes. They include proteins resulting from the fusion of an oncogene and another gene (ONCOGENE PROTEINS, FUSION).Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.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.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.Genes, jun: Retrovirus-associated DNA sequences (jun) originally isolated from the avian sarcoma virus 17 (ASV 17). The proto-oncogene jun (c-jun) codes for a nuclear protein which is involved in growth-related transcriptional control. Insertion of c-jun into ASV-17 or the constitutive expression of the c-jun protein produces tumorgenicity. The human c-jun gene is located at 1p31-32 on the short arm of chromosome 1.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.raf Kinases: A family of closely-related serine-threonine kinases that were originally identified as the cellular homologs of the retrovirus-derived V-RAF KINASES. They are MAP kinase kinase kinases that play important roles in SIGNAL TRANSDUCTION.Proto-Oncogene Proteins c-sis: Cellular DNA-binding proteins encoded by the sis gene (GENES, SIS). c-sis proteins make up the B chain of PLATELET-DERIVED GROWTH FACTOR. Overexpression of c-sis causes tumorigenesis.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.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Genes, myb: Retrovirus-associated DNA sequences (v-myb) originally isolated from the avian myeloblastosis and E26 leukemia viruses. The proto-oncogene c-myb codes for a nuclear protein involved in transcriptional regulation and appears to be essential for hematopoietic cell proliferation. The human myb gene is located at 6q22-23 on the short arm of chromosome 6. This is the point of break in translocations involved in T-cell acute lymphatic leukemia and in some ovarian cancers and melanomas. (From Ibelgaufts, Dictionary of Cytokines, 1995).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-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.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.Niacinamide: An important compound functioning as a component of the coenzyme NAD. Its primary significance is in the prevention and/or cure of blacktongue and PELLAGRA. Most animals cannot manufacture this compound in amounts sufficient to prevent nutritional deficiency and it therefore must be supplemented through dietary intake.Phenylurea Compounds: Compounds that include the amino-N-phenylamide structure.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.Pheochromocytoma: A usually benign, well-encapsulated, lobular, vascular tumor of chromaffin tissue of the ADRENAL MEDULLA or sympathetic paraganglia. The cardinal symptom, reflecting the increased secretion of EPINEPHRINE and NOREPINEPHRINE, is HYPERTENSION, which may be persistent or intermittent. During severe attacks, there may be HEADACHE; SWEATING, palpitation, apprehension, TREMOR; PALLOR or FLUSHING of the face, NAUSEA and VOMITING, pain in the CHEST and ABDOMEN, and paresthesias of the extremities. The incidence of malignancy is as low as 5% but the pathologic distinction between benign and malignant pheochromocytomas is not clear. (Dorland, 27th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1298)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 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.Drosophila Proteins: Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.Blotting, Northern: Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.NIH 3T3 Cells: A continuous cell line of high contact-inhibition established from NIH Swiss mouse embryo cultures. The cells are useful for DNA transfection and transformation studies. (From ATCC [Internet]. Virginia: American Type Culture Collection; c2002 [cited 2002 Sept 26]. Available from http://www.atcc.org/)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.Cell Line, Tumor: A cell line derived from cultured tumor cells.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.Oncogene Protein p21(ras): Transforming protein encoded by ras oncogenes. Point mutations in the cellular ras gene (c-ras) can also result in a mutant p21 protein that can transform mammalian cells. Oncogene protein p21(ras) has been directly implicated in human neoplasms, perhaps accounting for as much as 15-20% of all human tumors. This enzyme was formerly listed as EC 3.6.1.47.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Oligonucleotides, Antisense: Short fragments of DNA or RNA that are used to alter the function of target RNAs or DNAs to which they hybridize.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.