Year: 2005
Type: article
Abstract: Vinculin is autoinhibited by an intramolecular interaction that masks binding sites for talin and F-actin. Although a recent structural model explains autoinhibition solely in terms of the interaction between vinculin tail (Vt) and residues 1-258 (D1), we find an absolute requirement for an interface involving the D4 domain of head (Vh residues 710-836) and Vt. Charge-to-alanine mutations in Vt revealed a class of mutants, T12 and T19, distal to the V-(1-258) binding site, which showed increases in their Kd values for head binding of 100- and 42-fold, respectively. Reciprocal mutation of residues in the D4 domain that contact Vt yielded a head-tail interaction mutant of comparable magnitude to T19. These findings account for the approximately 120-fold difference in Kd values between Vt binding to V-(1-258), as opposed to full-length Vh-(1-851). The significance of a bipartite autoinhibitory site is evidenced by its effects on talin binding to Vh. Whereas Vt fails to compete with the talin rod domain for binding to V-(1-258), competition occurs readily with full-length Vh, and this requires the D4 interface. Moreover in intact vinculin, mutations in the D4-Vt interface stabilize association of vinculin and talin rod. In cells, these head-tail interaction mutants induce hypertrophy and elongation of focal adhesions. Definition of a second autoinhibitory site, the D4-Vt interface, supports the competing model of vinculin activation that invokes cooperative action of ligands at two sites. Together the D1-Vt and D4-Vt interfaces provide the high affinity (approximately 10(-9)) autoinhibition observed in full-length vinculin.
Source: Journal of Biological Chemistry
Authors: Daniel M. Cohen, Hui Chen, Robert P. Johnson, Begum Choudhury, Susan W. Craig
Language: English
Subfield: Immunology and Allergy
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
Award: G72895648
OpenAlex ID: W1983957728