5kho
Rasip1 RA domain in complex with Rap1BRasip1 RA domain in complex with Rap1B
Structural highlights
Function[RAIN_HUMAN] Required for the proper formation of vascular structures that develop via both vasculogenesis and angiogenesis. Acts as a critical and vascular-specific regulator of GTPase signaling, cell architecture, and adhesion, which is essential for endothelial cell morphogenesis and blood vessel tubulogenesis. Regulates the activity of Rho GTPases in part by recruiting ARHGAP29 and suppressing RhoA signaling and dampening ROCK and MYH9 activities in endothelial cells (By similarity). May act as effector for Golgi-bound HRAS and other Ras-like proteins. May promote HRAS-mediated transformation. Negative regulator of amino acid starvation-induced autophagy.[1] [2] [RAP1B_HUMAN] GTP-binding protein that possesses intrinsic GTPase activity. Contributes to the polarizing activity of KRIT1 and CDH5 in the establishment and maintenance of correct endothelial cell polarity and vascular lumen. Required for the localization of phosphorylated PRKCZ, PARD3 and TIAM1 to the cell junction.[3] [4] Publication Abstract from PubMedRas-interacting protein 1 (Rasip1) is an endothelial-specific Rap1 and Ras effector, important for vascular development and angiogenesis. Here, we report the crystal structure of the Rasip1 RA domain (RRA) alone, revealing the basis of dimerization, and in complex with Rap1 at 2.8 A resolution. In contrast to most RA domains, RRA formed a dimer that can bind two Rap1 (KD = 0.9 muM) or Ras (KD = 2.2 muM) molecules. We solved the Rap1-RRA complex and found that Rasip1 binds Rap1 in the Switch I region, and Rap1 binding induces few conformation changes to Rasip1 stabilizing a beta strand and an unstructured loop. Our data explain how Rasip1 can act as a Rap1 and Ras effector and show that Rasip1 defines a subgroup of dimeric RA domains that could mediate cooperative binding to membrane-associated Ras superfamily members. Structural Basis of Dimeric Rasip1 RA Domain Recognition of the Ras Subfamily of GTP-Binding Proteins.,Gingras AR, Puzon-McLaughlin W, Bobkov AA, Ginsberg MH Structure. 2016 Dec 6;24(12):2152-2162. doi: 10.1016/j.str.2016.10.001. Epub 2016, Nov 10. PMID:27839947[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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