Evidence for a Ras-dependent extracellular signal-regulated protein kinase (ERK) cascade.
The small GTP-binding protein Ras appears to be required for transformation and differentiation induced by tyrosine kinases. The Ras requirement may be limited to a few tyrosine kinase-regulated signaling pathways or may be universal for all tyrosine kinase actions. Because both Ras and the microtubule-associated protein 2 kinases ERK1 and ERK2 have been implicated in events that lead to neurite outgrowth, we explored the possibility that Ras and ERKs may lie on the same signaling pathway. Utilizing PC-12 rat adrenal pheochromocytoma cell lines that contain a dominant inhibitory Ras mutant (S17N-Ras(H)), we found that Ras was required for stimulation of the ERK cascade by nerve growth factor but apparently not by the heterotrimeric G protein activator AlF4-. Within this cascade, Ras appears to be upstream of an ERK activator, raising the intriguing possibility that Ras may directly regulate a serine/threonine protein kinase.
Robbins
D J
DJ
University of Texas Southwestern Medical Center, Department of Pharmacology, Dallas 75235-9041.
Cheng
M
M
Zhen
E
E
Vanderbilt
C A
CA
Feig
L A
LA
Cobb
M H
MH
D000535:Aluminum / Q000494:pharmacology; D017607:Aluminum Compounds; D000818:Animals; D005459:Fluorides; D005461:Fluorine / Q000494:pharmacology; D020690:GTPase-Activating Proteins; D011905:Genes, ras; D007700:Kinetics; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D009154:Mutation; D009414:Nerve Growth Factors / Q000494:pharmacology; D016716:PC12 Cells; D010766:Phosphorylation; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012190:Retroviridae / Q000235:genetics; D019893:Ribosomal Protein S6 Kinases; D015398:Signal Transduction; D014162:Transfection; D020703:ras GTPase-Activating Proteins
D017607:Aluminum Compounds; D020690:GTPase-Activating Proteins; D009414:Nerve Growth Factors; D011506:Proteins; D020703:ras GTPase-Activating Proteins; C050992:tetrafluoroaluminate; D005461:Fluorine; D000535:Aluminum; D011494:Protein Kinases; D019893:Ribosomal Protein S6 Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D005459:Fluorides