propose an important role for SSPN within the DGC, **data** from the SSPN-deficient mice (Lebakken et al., 2000) has not provided much insight into SSPN's function. SSPN-null mice exhibit wild-type levels of DGC protein expression and possess normal force and power generation capabilities (Lebakken et al., 2000). It is feasible that SSPN is replaced by a functionally similar tetraspanin during muscle development, which does not clarify the interpretation of SSPN's role in muscle physiology.