talin contains a c-terminal calpain2 cleavage site important in focal adhesion dynamics蛋白包含c端calpain2裂解位点重要焦点粘附动力学.pdfVIP

Talin Contains A C-Terminal Calpain2 Cleavage Site Important In Focal Adhesion Dynamics 1 1¤ 2 2 3 1 Neil Bate , Alexandre R. Gingras , Alexia Bachir , Rick Horwitz , Feng Ye , Bipin Patel , 1 1 Benjamin T. Goult , David R. Critchley * 1 Department of Biochemistry, University of Leicester, Leicester, United Kingdom, 2 Department of Cell Biology, Univeristy of Virginia School of Medicine, Charlottesville, Virginia, United States of America, 3 Department of Medicine, University of California San Diego, La Jolla, California, United States of America Abstract Talin is a large ( ,2540 residues) dimeric adaptor protein that associates with the integrin family of cell adhesion molecules in cell-extracellular matrix junctions (focal adhesions; FAs), where it both activates integrins and couples them to the actin cytoskeleton. Calpain2-mediated cleavage of talin between the head and rod domains has previously been shown to be important in FA turnover. Here we identify an additional calpain2-cleavage site that removes the dimerisation domain from the C-terminus of the talin rod, and show that an E2492G mutation inhibits calpain cleavage at this site in vitro, and increases the steady state levels of talin1 in vivo. Expression of a GFP-tagged talin1 E2492G mutant in CHO.K1 cells inhibited FA turnover and the persistence of cell protrusion just as effectively as a L432G mutation that inhibits calpain cleavage between the talin head and rod domains. Moreover, incorporation of both mutations into a single talin molecule had an additive effect clearly demonstrating that calpain cleavage at