Cytoskeletal signaling by way of alpha-actinin-1 mediates ERK1/2 activation by repetitive deformation in human Caco2 intestinal epithelial cells.

<bold>Background: </bold>Repetitive deformation stimulates proliferation in human Caco2 intestinal epithelial cells by way of an ERK1/2-dependent pathway. We examined the effects of cytoskeletal perturbation on deformation-induced signaling in Caco2 cells.<bold>Methods: </bold>The Caco2 cell cytoskeleton was disrupted with either cytochalasin D, phalloidin, colchicine, or paclitaxel. Levels of alpha-actinin-1 and -4 and paxillin were reduced by specific small interfering RNA. Cells on collagen I-precoated membranes were subjected to 10% repetitive deformation at 10 cycles/min. After 1 hour, cells were lysed for Western blot analysis.<bold>Results: </bold>Strain-activated ERK1/2, focal adhesion kinase, and Src phosphorylation in dimethyl sulfoxide- and/or nontargeting small interfering RNA-treated control cell populations. Cytochalasin D and paclitaxel, but not phalloidin and colchicine, blocked ERK1/2 phosphorylation. A decrease in alpha-actinin-1, but not in alpha-actinin-4 or paxillin, inhibited ERK1/2 and focal adhesion kinase phosphorylation, whereas Src activation appears to be independent of these effects.<bold>Conclusions: </bold>The intestinal epithelial cell cytoskeleton may transduce mechanical signals by way of alpha-actinin-1 into the focal adhesion complex, culminating in ERK1/2 activation and proliferation. [ABSTRACT FROM AUTHOR]