skNAC depletion stimulates myoblast migration and perturbs sarcomerogenesis by enhancing calpain 1 and 3 activity

Skeletal and heart muscle specific variant of nascent polypeptide associated complex (skNAC) is a skeletal and heart muscle-specific protein known to be involved in the regulation of sarcomerogenesis. The respective mechanism, however, is largely unknown. Here, we demonstrate that skNAC regulates calpain activity. Specifically, we show that inhibition of skNAC expression leads to enhanced, and overexpression of the skNAC gene to repressed, activity of calpain 1 and – to a lesser extent – calpain 3 in myoblasts. In skNAC siRNA-treated cells, enhanced calpain activity is associated with increased migration rates, as well as with perturbed sarcomere architecture. Treatment of skNAC knockdown cells with the calpain inhibitor ALLN reverts both the positive effect on myoblast migration and the negative effect on sarcomere architecture. Taken together, our data suggest that skNAC controls myoblast migration and sarcomere architecture in a calpain-dependent manner.

Source: BJ Cell - May 13, 2013 Category: Biochemistry Authors: J Berkholz, A Zakrzewicz, B Munz Tags: BJ Cell Source Type: research