Tensin can induce JNK and p38 activation

Cells organize diverse types of specialized adhesion sites upon attachment to extracellular matrix (ECM) components. One of the physiological roles of such cell-ECM interactions is to initiate and regulate adhesion-mediated s ignal transduction responses. The association of cells with fibronectin fib rils has been shown to regulate the JNK and p38 signaling pathways. We test ed whether tensin, a cytoskeletal component localized to both focal contact s and fibronectin-associated fibrillar adhesions, can induce these signalin g pathways. We found that tensin overexpression resulted in activation of b oth the c-Jun amino-terminal kinase (JNK) and p38 pathways. Tensin-mediated JNK activation was independent of the activities of the small GTP binding proteins Rac and Cdc42, but did depend on SEK, a kinase involved in the JNK pathway. We suggest that tensin may directly activate the JNK and p38 path ways, acting downstream or independent of the activities of the small GTP b inding proteins Rac and Cdc42. (C) 2000 Academic Press.