Degradation of focal adhesion proteins during nocodazole-induced apoptosisin rat-1 cells

Nocodazole, a microtubule-disrupting agent, induced apoptosis in Rat-1 cell s. as indicated by changes in cell morphology, DNA fragmentation, and event ual cell death. During nocodazole-induced apoptosis, normally flat cells be came rounded in shape and detached from the extracellular matrix. These mor phological changes appeared to be closely associated with degradation of fo cal adhesion proteins, including p130cas, p125(FAK) and paxillin. p130cas w as also degraded in cells treated with staurosporine or etoposide, suggesti ng that degradation of focal adhesion proteins is a characteristic feature of apoptosis. Nocodazole-induced apoptosis was antagonized by Bcl-2: degrad ation of focal adhesion proteins was suppressed and cell viability was enha nced in bcl-2 over-expressing cells. even in the presence of nocodazole. Fu rther study of the molecular mechanism of Bcl-2 activation should provide a n understanding of the apoptosis induced by disruption of the microtubule n etwork. Copyright (C) 2000 John Wiley & Sons, Ltd.