It is well established that mitogens inhibit differentiation of skeletal muscle cells, but the
insulin-like growth factors (IGFs), acting through a single receptor, stimulate both
proliferation and differentiation of myoblasts. Although the IGF-I mitogenic signaling pathway
has been extensively studied in other cell types, little is known about the signaling pathway
leading to differentiation in skeletal muscle. By using specific inhibitors of the IGF signal
transduction pathway, we have begun to define the signaling intermediates mediating the …