Role of the cAMP-dependent protein kinase and protein kinase C in regulating the morphological differentiation of PC12 cells.
The cell line A126-1B2 is a PC12-derived mutant that is resistant to the toxic effects of dibutyryladenosine 3':5'-cyclic monophosphate (dbcAMP) and is deficient in adenosine 3':5'-cyclic monophosphate (cAMP)-dependent protein kinase II (PKAII). This mutant formed neurites in response to nerve growth factor (NGF), but not in response to dbcAMP; and dbcAMP did not increase the rate of NGF-dependent neurite formation. Thus, while PKAII is essential for process formation in response to agents that act through the cAMP-dependent pathway, activation of PKAII is not essential for NGF-dependent neurite formation. Unexpectedly, NGF and phorbol 12-myristate 13-acetate (PMA; 10-1,000 nM) synergistically stimulated the formation of short processes that were apparent within 30 min of NGF addition in 85% of these mutant cells. These processes were similar, but not identical, in appearance to the NGF-dependent neurites that formed only after a period of 24-48 hr. This effect is dependent on the activation of protein kinase C (PKC) because an inactive phorbol ester was without effect. In contrast, there was only a small effect of NGF and/or PMA on process formation in wild type cells within the first few hours. The effect of PMA is not augmented by dbcAMP in the A126-1B2 mutant cells. After several hours, PMA caused a concentration-dependent decrease in cell adhesion; and higher concentrations of PMA resulted in a transient detachment of the cells and a loss of neurites. These experiments suggest a role for PKC in the regulation of process formation.
Glowacka
D
D
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts.
Wagner
J A
JA
D000310:Adrenal Gland Neoplasms; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation; D002460:Cell Line; D000242:Cyclic AMP / Q000494:pharmacology / Q000502:physiology*; D004347:Drug Interactions; D009414:Nerve Growth Factors / Q000494:pharmacology* / Q000502:physiology; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D010673:Pheochromocytoma; D011493:Protein Kinase C / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology*; D051381:Rats; D015290:Second Messenger Systems; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D009414:Nerve Growth Factors; D000242:Cyclic AMP; D011494:Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate