Fig. 9. Schematic summary of the proposed roles of GC and SM UNC-45, based on the processes inhibited by antisense reduction of specific mRNAs. GC UNC-45 functions in cytoskeletal processes in proliferating, non-differentiating cells. Both GC and SM UNC-45 function in myotube formation through cell fusion. Myofibril formation requires both GC and SM UNC-45, consistent with the fact that the cytoskeleton is necessary for the development and maintenance of organized myofibrils.