title: Regulation of p21ras activity.
abstract: The ras genes encode GTP/GDP-binding proteins that participate in mediating mitogenic signals from membrane tyrosine kinases to downstream targets. The activity of p21ras is determined by the concentration of GTP-p21ras, which is tightly regulated by a complex array of positive and negative control mechanisms. GAP and NF1 can negatively regulate p21ras activity by stimulating hydrolysis of GTP bound to p21ras. Other cellular factors can positively regulate p21ras by stimulating GDP/GTP exchange.
authors.affiliation: Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, MD 20892.
authors.forename: D R
authors.initials: DR
authors.lastname: Lowy
authors.forename: K
authors.initials: K
authors.lastname: Zhang
authors.forename: J E
authors.initials: JE
authors.lastname: DeClue
authors.forename: B M
authors.initials: BM
authors.lastname: Willumsen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020690:GTPase-Activating Proteins; D005786:Gene Expression Regulation; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008322:Mammals / Q000235:genetics / Q000502:physiology; D008954:Models, Biological; D008969:Molecular Sequence Data; D025542:Neurofibromin 1; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000502:physiology; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D020703:ras GTPase-Activating Proteins; D018631:ras Proteins
chemical_list: D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D025542:Neurofibromin 1; D011506:Proteins; D020703:ras GTPase-Activating Proteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins