4dx9
ICAP1 in complex with integrin beta 1 cytoplasmic tailICAP1 in complex with integrin beta 1 cytoplasmic tail
Structural highlights
FunctionITBP1_HUMAN Regulates integrin signaling by binding to the ITGB1 cytoplasmic tail and preventing the activation of integrin alpha-5/beta-1 (heterodimer of ITGA5 and ITGB1) by talin or FERMT1. May play a role in the recruitment of ITGB1 to focal contacts during integrin-dependent cell adhesion.[REFERENCE:8] Publication Abstract from PubMedKRIT1 (Krev/Rap1 Interaction Trapped-1) mutations are observed in approximately 40% of autosomal-dominant cerebral cavernous malformations (CCMs), a disease occurring in up to 0.5% of the population. We show that KRIT1 functions as a switch for beta1 integrin activation by antagonizing ICAP1 (Integrin Cytoplasmic Associated Protein-1)-mediated modulation of "inside-out" activation. We present cocrystal structures of KRIT1 with ICAP1 and ICAP1 with integrin beta1 cytoplasmic tail to 2.54 and 3.0 A resolution (the resolutions at which I/sigmaI = 2 are 2.75 and 3.0 A, respectively). We find that KRIT1 binds ICAP1 by a bidentate surface, that KRIT1 directly competes with integrin beta1 to bind ICAP1, and that KRIT1 antagonizes ICAP1-modulated integrin activation using this site. We also find that KRIT1 contains an N-terminal Nudix domain, in a region previously designated as unstructured. We therefore provide insights to integrin regulation and CCM-associated KRIT1 function. Mechanism for KRIT1 Release of ICAP1-Mediated Suppression of Integrin Activation.,Liu W, Draheim KM, Zhang R, Calderwood DA, Boggon TJ Mol Cell. 2013 Jan 9. pii: S1097-2765(12)01014-3. doi:, 10.1016/j.molcel.2012.12.005. PMID:23317506[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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