Wech proteins: roles in integrin functions and beyond.

Members of the integrin family of cell adhesion receptors are pivotal to the formation of complex tissues and organs in animals. They mediate cell adhesion by interacting with the extracellular matrix and by binding to intracellular linker proteins that connect to the cytoskeleton. We have recently identified a new and evolutionarily conserved component of the linker complex, the Drosophila Wech protein. Wech is essential for embryonic muscle attachment. It belongs to the RBCC/TRIM family of cytoplasmic multidomain proteins and contains a carboxyterminal NHL domain. Wech protein is specifically localized to the embryonic muscle attachment sites and wech mutant embryos show muscle detachment from the body wall. In beta-integrin or talin mutants Wech is mislocalized, as the localization of Integrin-linked-kinase (ILK) depends on Wech. Biochemical data indicate that Wech is associated with the head domain of Talin and the kinase domain of ILK suggesting that Wech may be involved in the linkage of both core proteins of the linker complex. We discuss that Wech proteins may be crucial and evolutionarily conserved regulators of cell-type specific integrin functions and that their activities may underlie complex regulation by microRNAs.