The role of protein kinase C in laminin-mediated neurite outgrowth

Laminin is a potent stimulator of neurite outgrowth in rat pheochromocytoma (PC12) cells. Here, we investigated the role of protein kinase C (PKC) in the mechanism of laminin-mediated neurite outgrowth in PC12 cells. Phorbol ester activators of PKC have been shown to have divergent effects on laminin-mediated neurite outgrowth. Therefore, we tested the effect of the non-phorbol PKC activator, indolactam V. At 1.0 microM indolactam V inhibited laminin-mediated neurite outgrowth by 85%. Further, the PKC inhibitor H7 blocked the inhibitory effect of indolactam V on laminin-mediated neurite outgrowth. Direct measurement of protein kinase C activity in the soluble (cytosolic) and particulate (membrane) fractions of PC12 cells showed that laminin failed to alter protein kinase C activity. These data demonstrate that PKC activation inhibits laminin-mediated neurite outgrowth and that laminin does not activate PKC in PC12 cells.