Skeletal muscle adaptation in response to mechanical stress in p130cas^-/-mice

Mammalian skeletal muscles undergo adaptation in response to changes in the functional demands upon them, involving mechanical-stress-induced cellular signaling called "mechanotransduction." We hypothesized that p130Cas, which is reported to act as a mechanosensor that transduces mechanical extension into cellular signaling, plays an important role in maintaining and promoting skeletal muscle adapta-tion in response to mechanical stress via the p38 MAPK signaling pathway. We demonstrate that muscle-specific p130Cas^-/-mice express the contractile proteins normally in skeletal muscle. Further-more, muscle-specific p130Cas^-/-mice show normal mechanical-stress-induced muscle adaptation, including exercise-induced IIb-to-IIa muscle fiber type transformation and hypertrophy. Finally, we provide evidence that exercise-induced p38 MAPK signaling is not impaired by the muscle-specific deletion of p130Cas. We conclude that p130Cas plays a limited role in mechanical-stress-induced skel-etal muscle adaptation.