Abstract

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During differentiation of mouse myoblasts into myotubes, rate of global protein synthesis is decreased to slow down the cell cycle and ultimately cells enter into the quiescent stage. To determine the molecular mechanism of this inhibition of rate of protein synthesis during differentiation, we measured the phosphorylation of eIF2α and its association with p67. Our results show that the phosphorylation of eIF2α during differentiation of C2C12 myoblasts into myotube is increased significantly and is mediated by an unknown kinase, which is not the double-stranded RNA activated kinase, PKR. The level of eIF2α phosphorylation during this differentiation correlates with the inhibition of rates of global protein synthesis and its dissociation from eIF2/p67 complex. Together, our data suggest that dissociation of p67 from eIF2 complex plays an important role to slow down the rates of global protein synthesis during C2C12 myoblasts’ differentiation in myotubes.

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