A cytoplasmic protein inhibits the GTPase activity of H-Ras in a phospholipid-dependent manner.
A cytoplasmic protein has been identified that inhibits the guanosine triphosphatase (GTPase) activity of bacterially synthesized, cellular H-Ras protein. This GTPase inhibiting protein is able to counteract the activity of GTPase activating protein (GAP), which has been postulated to function as a negative regulator of Ras activity. The potential biological importance of the GTPase inhibiting protein is further supported by its interaction with lipids. Phospholipids produced in cells as a consequence of mitogenic stimulation increase the activity of the GTPase inhibiting protein, as well as inhibit the activity of GAP. The interaction of such lipids with each of these two regulatory proteins would, therefore, tend to increase the biological activity of Ras and stimulate cell proliferation.
Tsai
M H
MH
Department of Molecular Biology, Cleveland Clinic Foundation 44195.
Yu
C L
CL
Stacey
D W
DW
D000818:Animals; D002455:Cell Division; D004305:Dose-Response Relationship, Drug; D020558:GTP Phosphohydrolases / Q000037:antagonists & inhibitors*; D020690:GTPase-Activating Proteins; D051379:Mice; D010743:Phospholipids / Q000494:pharmacology*; D011506:Proteins / Q000037:antagonists & inhibitors; D016283:Proto-Oncogene Proteins p21(ras) / Q000037:antagonists & inhibitors*; D020703:ras GTPase-Activating Proteins
D020690:GTPase-Activating Proteins; D010743:Phospholipids; D011506:Proteins; D020703:ras GTPase-Activating Proteins; D020558:GTP Phosphohydrolases; D016283:Proto-Oncogene Proteins p21(ras)