Role of Annexin A1 in Mouse Myoblast Cell Differentiation

Annexin Al (ANXAI) is a calcium- and phospholipid-binding protein involved in a broad range of cellular events. This study used molecular and microscopy approaches to explore the role of ANXAI in mouse myoblast C(2)Cl(2) cell differentiation. We report that ANXAI expression increases during differentiation and that the down-regulation of ANXAI significantly inhibits the differentiation process. ANXAI is expressed in vivo in both quiescent and activated satellite cells and is highly localized in the cells that migrate in the lumen of regenerating fibers after an acute injury. Endogenous ANXAI co-localizes with actin fibers at the protruding ends of undifferentiated but not differentiated cells suggesting a role of the protein in cell migration. Furthermore, ANXAI neutralizing antibody reduces MyHC expression, decreases myotube formation and significantly inhibits cell migration. The data reported here suggest for the first time that ANXAI plays a role in myogenic differentiation. J. Cell. Physiol. 224: 757-765, 2010. (C) 2010 Wiley-Liss, Inc.