Developmental expression of G αo and G αs isoforms in PC12 cells: relationship to neurite outgrowth

Recent evidence suggests neuronal differentiation is associated with developmentally regulated changes in the expression of certain G-protein subtypes but the relationship of such changes to neuronal differentiation and/or neurite outgrowth is poorly understood. In this study, the appearance of the G-protein α o and α s subunit isoforms was characterized in NGF-induced differentiating pheochromocytoma (PC)12 cells and correlated with neurite outgrowth, which was assessed with direct morphometric measures at 24-h intervals for a 5-day period and at 24, 48 and 72 h following NGF removal. Significant increases were observed in α o1 immunoreactive levels and the ratio of α o1 α o2 immunoreactivities during NGF exposure but not in the levels of either the long or short isoform of α s. The former changes also correlated significantly with neurite length during NGF treatment. Furthermore, no significant changes were observed in the levels of α o or α s isoforms following NGF removal. These findings suggest that α o isoforms are involved in neuritic extension in PC12 cells.