2ibf | pdb_00002ibf
Human vinculin's head domain (Vh1, residues 1-258) in complex with two vinculin binding sites of Shigella flexneri's IpaA (residues 565-587)
Structural highlights
Disease[VINC_HUMAN] Defects in VCL are the cause of cardiomyopathy dilated type 1W (CMD1W) [MIM:611407]. Dilated cardiomyopathy is a disorder characterized by ventricular dilation and impaired systolic function, resulting in congestive heart failure and arrhythmia. Patients are at risk of premature death.[1] [2] Defects in VCL are the cause of familial hypertrophic cardiomyopathy type 15 (CMH15) [MIM:613255]. It is a hereditary heart disorder characterized by ventricular hypertrophy, which is usually asymmetric and often involves the interventricular septum. The symptoms include dyspnea, syncope, collapse, palpitations, and chest pain. They can be readily provoked by exercise. The disorder has inter- and intrafamilial variability ranging from benign to malignant forms with high risk of cardiac failure and sudden cardiac death.[3] Function[VINC_HUMAN] Actin filament (F-actin)-binding protein involved in cell-matrix adhesion and cell-cell adhesion. Regulates cell-surface E-cadherin expression and potentiates mechanosensing by the E-cadherin complex. May also play important roles in cell morphology and locomotion.[4] [IPAA_SHIFL] Rapidly associates with the first 265 amino acids of vinculin after bacteria-cell contact. This interaction is critical for efficient Shigella uptake. IpaA acts as a potent activator of vinculin and increase its ability to interact with F-actin. The complex IpaA-vinculin induces F-actin depolymerization along with the occasional formation of actin filament bundles.[5] [6] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedVinculin links integrin receptors to the actin cytoskeleton by binding to talin. Vinculin is held in an inactive, closed-clamp conformation through hydrophobic interactions between its head and tail domains, and vinculin activation has long been thought to be dependent upon severing the head-tail interaction. Talin, alpha-actinin, and the invasin IpaA of Shigella flexneri sever vinculin's head-tail interaction by inserting an alpha-helix into vinculin's N-terminal four-helical bundle, provoking extensive conformational changes by a helical bundle conversion mechanism; these alterations in vinculin structure displace its tail domain, allowing vinculin to bind to its other partners. IpaA harbors two juxtaposed alpha-helical vinculin-binding sites (VBS) in its C-terminus. Here, we report that the lower affinity VBS of IpaA can also bind to the adjacent C-terminal four-helical bundle of vinculin's head domain through a helix addition mechanism. These hydrophobic interactions do not alter the conformation of this helical bundle, and the architecture of the complex suggests that IpaA can simultaneously interact with both of the four-helical bundle domains of vinculin's N-terminus to stabilize vinculin-IpaA interactions. Vinculin binding in its closed conformation by a helix addition mechanism.,Nhieu GT, Izard T EMBO J. 2007 Oct 31;26(21):4588-96. Epub 2007 Oct 11. PMID:17932491[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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