Constitutive overexpression of the integral membrane protein Itm2A enhances myogenic differentiation of C2C12 cells.

Integral membrane protein 2A (Itm2A) is a transmembrane protein belonging to a family composed of at least two other members, Itm2B and Itm2C, all of them having a different expression pattern. The protein serves as a marker for early stages in chondrogenesis and T-cell development. Itm2A is also highly expressed in skeletal muscle. In order to understand the role of Itm2A in muscle development, we constitutively overexpressed exogenous Itm2A in C2C12 myoblast cells. Several clones expressing high levels of Itm2a were isolated and characterized. Overexpression was associated with enhanced tube formation and the appearance of multinuclear cells. Gene expression analysis demonstrated that muscle creatin kinase was upregulated in the presence of exogenous Itm2A. Interestingly, proliferation rates were not altered in the undifferentiated myoblast C2C12 cells. These results demonstrate that overexpression of Itm2a in C2C12 enhances myogenic differentiation in vitro.