Stimulation of a Ca(2+)-dependent protein kinase by GM1 ganglioside in nerve growth factor-treated PC12 cells.
We have investigated the ability of exogenous gangliosides to modulate nerve growth factor (NGF) signal transduction in PC12 cells. The effects of exogenous ganglioside GM1 on multiple protein kinase activities were assayed by analyzing site-specific serine phosphorylation of tyrosine hydroxylase (TyrOHase) by two-dimensional phosphopeptide mapping. In the presence of NGF, exogenous GM1 (1-10 microM) increased 32P incorporation into TyrOHase phosphopeptide T2, a Ca2+/calmodulin-dependent protein kinase substrate whose phosphorylation is not normally affected by NGF treatment. In the absence of NGF, GM1 treatment had no significant effects on TyrOHase phosphorylation. The removal of extracellular Ca2+ or blockade of dihydropyridine-sensitive Ca2+ channels prevented the GM1-induced increases in 32P incorporation into phosphopeptide T2. Exogenous GM1 also potentiated K+ depolarization-induced increases in the phosphorylation of TryOHase. These results suggest that the stimulatory effects of exogenous GM1 ganglioside on NGF actions may be due to its ability to potentiate a Ca(2+)-dependent signaling pathway.
Department of Neurobiology and Behavior, State University of New York, Stony Brook 11794-5230.
B S
BS
Hilbush
J M
JM
Levine
D000310:Adrenal Gland Neoplasms / Q000503:physiopathology; D000818:Animals; D002118:Calcium / Q000502:physiology; D002772:Cholera Toxin / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005677:G(M1) Ganglioside / Q000494:pharmacology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology; D010449:Peptide Mapping; D010673:Pheochromocytoma / Q000503:physiopathology*; D011188:Potassium / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases
D002118:Calcium; D002772:Cholera Toxin; D005677:G(M1) Ganglioside; D009414:Nerve Growth Factors; D011188:Potassium; D011494:Protein Kinases; D014446:Tyrosine 3-Monooxygenase; D017871:Calcium-Calmodulin-Dependent Protein Kinases