Papers Published
Abstract:
Transient receptor potential (TRIP) channels are nonselective cation channels, several of which are expressed in striated muscle. Because the scaffolding protein Homer 1 has been implicated in TRP channel regulation, we hypothesized that Homer proteins play a significant role in skeletal muscle function. Mice lacking Homer I exhibited a myopathy characterized by decreased muscle fiber cross-sectional area and decreased skeletal muscle force generation. Homer I knockout myotubes displayed increased basal current density and spontaneous cation influx. This spontaneous cation influx in Homer I knockout myotubes was blocked by reexpression of Homer 1b, but not Homer la, and by gene silencing of TRPC1. Moreover, diminished Homer 1 expression in mouse models of Duchenne's muscular dystrophy suggests that loss of Homer I scaffolding of TRP channels may contribute to the increased stretch-activated channel activity observed in mdr myofibers. These findings provide direct evidence that Homer 1 functions as an important scaffold for TRP channels and regulates mechanotransduction in skeletal muscle.