title: Viral p21 Ki-RAS protein: a potent intracellular mitogen that stimulates adenylate cyclase activity in early G1 phase of cultured rat cells.
abstract: Rat kidney (NRK) cells infected with a temperature-sensitive mutant of the Kirsten sarcoma virus were arrested in the G0/G1 phase of their cell cycle by incubation in serum-deficient medium at a p21-inactivating temperature of 41 degrees C. These quiescent ts K-NRK cells were then stimulated to transit G1 and initiate DNA replication by lowering the temperature to 36 degrees C, which rapidly reactivated p21. Reactivating the viral Ki-RAS protein by temperature shift led to an increase in adenylate cyclase activity in early G1 phase. The Ki-RAS protein increased the sensitivity of adenylate cyclase to guanyl nucleotides by a mechanism that seemed to involve inactivation of the enzyme's inhibitory G1 regulatory protein.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D007708:Kirsten murine sarcoma virus / Q000235:genetics; D009857:Oncogenes; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D051381:Rats
chemical_list: D011518:Proto-Oncogene Proteins; D006165:Guanylyl Imidodiphosphate; D016283:Proto-Oncogene Proteins p21(ras); D000262:Adenylyl Cyclases