The 38-amino-acid form of pituitary adenylate cyclase-activating polypeptide induces neurite outgrowth in PC12 cells that is dependent on protein kinase C and extracellular signal-regulated kinase but not on protein kinase A, nerve growth factor receptor tyrosine kinase, p21(ras) G protein, and pp60(c-src) cytoplasmic tyrosine kinase.
The 38-amino-acid isoform of pituitary adenylate cyclase-activating polypeptide (PACAP38) elicits a robust outgrowth of neurites in cultured PC12 cells. Initiation of neurite outgrowth occurs within 4-8 hr after the addition of PACAP38. Treatment with PACAP38 does not elicit collateral activation of p140(trk) nerve growth factor receptor tyrosine kinase activity, nor is it associated with tyrosine phosphorylation of suc1-associated neurotrophic factor target, a selective target of neurotrophin tyrosine kinase receptors. Coadministration of epidermal growth factor with PACAP38 elicits an enhanced response. Induction of neurites is also observed on the addition of PACAP38 to dominant negative Src and Ras PC12 cell variants. PACAP38 stimulates extracellular signal-regulated kinase (Erk) activity >10-fold within 5 min, and the effect is augmented by cotreatment with epidermal growth factor. Pretreatment with the cAMP-dependent protein kinase-selective inhibitor, H-89, is ineffective as an antagonist of PACAP38-induced neurite outgrowth, whereas down-regulation of protein kinase C (PKC) by phorbol ester or incubation with PKC-selective inhibitors GF109203X and calphostin C effectively blocks PACAP38-stimulated neurite formation. Stimulation of Erk activity is inhibited by incubation with PD90859, a pharmacological antagonist of the threonine/tyrosine dual-specificity Erk. Inhibition of ligand-stimulated Erk activation prevents PACAP38-induced neurite outgrowth. Collectively, these findings indicate that PACAP38-stimulated neuritogenesis requires PKC and Erk activation but is independent of cAMP-dependent protein kinase, nerve growth factor receptor tyrosine kinase, p21(ras) G protein, and pp60(c-src) cytoplasmic tyrosine kinase.
Lazarovici
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Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91010, Israel.
Jiang
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H
Fink
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D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D004357:Drug Synergism; D004815:Epidermal Growth Factor / Q000494:pharmacology; D048728:MAP Kinase Kinase Kinase 1; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016501:Neurites / Q000187:drug effects*; D009479:Neuropeptides / Q000494:pharmacology*; D016716:PC12 Cells / Q000187:drug effects; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011493:Protein Kinase C / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D016283:Proto-Oncogene Proteins p21(ras) / Q000502:physiology*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000502:physiology*; D051381:Rats; D020917:Receptor, trkA; D017475:Receptors, Nerve Growth Factor / Q000502:physiology*; D013268:Stimulation, Chemical
C495402:Adcyap1 protein, mouse; C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011518:Proto-Oncogene Proteins; D017475:Receptors, Nerve Growth Factor; D004815:Epidermal Growth Factor; D020917:Receptor, trkA; D016392:Proto-Oncogene Proteins pp60(c-src); D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; C482578:Map3k1 protein, mouse; D016283:Proto-Oncogene Proteins p21(ras)