Stabilization of calpain large subunits by overexpression of truncated calpain small subunit in L8 myoblasts.

摘要

The objectives were to investigate the function of the small subunit in the calpain system by expression of the autolytic form of this subunit in L8 myoblasts. Rat post-autolysis small subunit (21kDa) cDNA expression plasmid was transfected into L8 myoblasts and selected by G418 containing medium. The concentrations of cytosolic micro-calpain in transfected cells, SS2 and SS3, were found to be 15.7 and 17.3% higher than that in L8Neo control cells, and the concentrations of cytosolic m-calpain in SS2 and SS3 cells were 23.3 and 16.6% higher than that in control cells (L8Neo). The half-life of micro-calpain in SS3 cells (36.5h) was longer than that in L8Neo cells (32.4h), while the half-life of m-calpain in SS3 cells (40.1h) was longer than that in L8Neo cell (37.5h). These results indicated that the expression of truncated small subunit increased the stability of micro- and m-calpain large subunits in cytosol.