Viral p21 Ki-RAS protein: a potent intracellular mitogen that stimulates adenylate cyclase activity in early G1 phase of cultured rat cells |
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Authors: | D J Franks J F Whitfield J P Durkin |
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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. |
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Keywords: | c-AMP G-proteins Ki-ras oncogene proliferation transformation |
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