Integrin α7β1 is the major laminin binding integrin receptor of muscle cells. The α7 chain
occurs in several splice isoforms, of which α7A and α7B differ in their intracellular domains
only. The fact that the expression of α7A and α7B is tightly regulated during skeletal muscle
development suggests different and distinct roles for both isoforms. However, so far,
functional properties and interacting proteins were described for the α7B chain only. Using a
yeast two-hybrid screen, we have found that Def-6, a guanine nucleotide exchange factor for …