G beta gamma subunits mediate mitogen-activated protein kinase activation by the tyrosine kinase insulin-like growth factor 1 receptor.
The receptors for insulin-like growth factor 1 (IGF1) and insulin are related heterotetrameric proteins which, like the epidermal growth factor (EGF) receptor, possess intrinsic ligand-stimulated tyrosine protein kinase activity. In Rat 1 fibroblasts, stimulation of mitogen-activated protein (MAP) kinase via the IGF1 receptor and the Gi-coupled receptor for lysophosphatidic acid (LPA), but not via the EGF receptor, is sensitive both to pertussis toxin treatment and to cellular expression of a specific G beta gamma subunit-binding peptide. The IGF1, LPA, and EGF receptor-mediated signals are all sensitive to inhibitors of tyrosine protein kinases, require p21ras activation, and are independent of protein kinase C. These data suggest that some tyrosine kinase growth factor receptors (e.g. IGF1 receptor) and classical G protein-coupled receptors (e.g. LPA receptor) employ a similar mechanism for mitogenic signaling that involves both tyrosine phosphorylation and G beta gamma subunits derived from pertussis toxin-sensitive G proteins.
Luttrell
L M
LM
Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
van Biesen
T
T
Hawes
B E
BE
Koch
W J
WJ
Touhara
K
K
Lefkowitz
R J
RJ
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002478:Cells, Cultured; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000502:physiology*; D037342:Pertussis Toxin; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D017526:Receptor, IGF Type 1 / Q000502:physiology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D017526:Receptor, IGF Type 1; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019204:GTP-Binding Proteins