Analysis of protein kinase C isoforms involved in the activation of laminin receptor in Raw264.7 macrophages.

Adherence of hematopoietic macrophages to a laminin (LM) substratum requires protein kinase C (PKC)-dependent activation of LM receptor. This study was performed to analyze PKC isoform(s) leading to the activation of LM receptor during Raw264.7 macrophage-like cell adhesion to a LM substratum. Raw264.7 cells expressed multiple PKC isoforms, including alpha, beta I, delta, epsilon, zeta, lambda/iota, and mu. Among the PKC isoforms expressed, selective activation of PKC delta and epsilon was sufficient to induce cell adhesion to LM. PKC-dependent cell adherence was blocked by the selective inhibition of PKC delta, suggesting that PKC delta was the responsible PKC isoform leading to activation of LM receptor. PKC delta appeared to activate LM receptor in an intact microfilament-dependent pathway, because disruption of microfilament inhibited cell adhesion to LM without affecting PKC delta activation.