부산대학교 도서관

Mitogen-activated protein kinases (MAPK) are important mediators of signal transduction from the cell surface to the nucleus. These MAPK pathways serve different receptor-mediated signaling pathways leading to dual phosphorylation on serine/threonine and tyrosine residues. The mechanisms linking cytoplasmic MAPK activation to later events is still unclear. In this study we demonstrate that the microfilament system has an active role in MAPK activation. Cross-linking of surface IgM or direct activation of PKC with PMA resulted in time and concentration-dependent increases in F-actin content, MAPK (p42erk-2) activation, and phosphorylation of p90rsk. Pretreatment of the B cells with cytochalasin D or botulinum C2toxin, microfilament-disrupting agents, prevented the increases in F-actin content as well as MAPK and p90rskactivation. These data indicate a role for the microfilament system in the complex and divergent functions of MAPK.