Caspase-1-induced calpastatin degradation in myoblast differentiation and fusion: cross-talk between the caspase and calpain systems.
Previously, we found that calpastatin diminished transiently prior to myoblast fusion (rat L8 myoblasts), allowing calpain-induced protein degradation, required for fusion. Here we show that the transient diminution in calpastatin is due to its degradation by caspase-1. Inhibition of caspase-1 prevents calpastatin diminution and prevents myoblast fusion. Caspase-1 activity is transiently increased during myoblast differentiation. Both calpain and caspase appear to be responsible for the fusion-associated membrane protein degradation. Caspase-1 has been implicated in the activation of proinflammatory cytokines, and in cell apoptosis. The involvement of caspase-1 in L8 myoblast fusion represents a novel function for this caspase in a non-apoptotic differentiation process, and points to cross-talk between the calpain and caspase systems in some differentiation processes.
Barnoy
Sivia
S
Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel Aviv 69978, Israel.
Kosower
Nechama S
NS
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002154:Calpain / Q000378:metabolism*; D020170:Caspase 1 / Q000378:metabolism*; D002454:Cell Differentiation; D002459:Cell Fusion; D002460:Cell Line; D006868:Hydrolysis; D018482:Muscle, Skeletal / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D051381:Rats
D002135:Calcium-Binding Proteins; C033668:calpastatin; D002154:Calpain; D020170:Caspase 1