DYNAMIC PALMITOYLATION OF NEUROMODULIN (GAP-43) IN CULTURED RAT CEREBELLAR NEURONS AND MOUSE N1E-115 CELLS

We conducted pulse-chase and metabolic labeling experiments to determi ne directly whether palmitoylation of neuromodulin in neurons is dynam ic, and if acylation is regulated. The rates of turnover of neuromodul in protein and associated palmitoyl groups were quantified using cultu red cerebellar granule neurons and the neuronal cell line N1E-115. The half-life of [H-3]palmitate bound to neuromodulin was approximately 5 h, whereas the half-life of the [S-35]methionine-labeled neuromodulin was greater than 50 h. Metabolic and pulse-chase labeling experiments were carried out in the presence of various activators of cellular si gnaling pathways. Our data indicate that dynamic acylation and deacyla tion of neuromodulin in neurons are constitutive and are not regulated by G protein activation or other signals that control growth cone dyn amics. (C) 1997 Elsevier Science Ireland Ltd.