5ffg
From Proteopedia
Crystal structure of integrin alpha V beta 6 head
Structural highlights
Disease[ITB6_HUMAN] Hypocalcified amelogenesis imperfecta;Hypoplastic amelogenesis imperfecta. Function[ITAV_HUMAN] The alpha-V integrins are receptors for vitronectin, cytotactin, fibronectin, fibrinogen, laminin, matrix metalloproteinase-2, osteopontin, osteomodulin, prothrombin, thrombospondin and vWF. They recognize the sequence R-G-D in a wide array of ligands. In case of HIV-1 infection, the interaction with extracellular viral Tat protein seems to enhance angiogenesis in Kaposi's sarcoma lesions. [ITB6_HUMAN] Integrin alpha-V/beta-6 is a receptor for fibronectin and cytotactin. It recognizes the sequence R-G-D in its ligands. Internalisation of integrin alpha-V/beta-6 via clathrin-mediated endocytosis promotes carcinoma cell invasion.[1] Publication Abstract from PubMedIntegrins are adhesion receptors that transmit force across the plasma membrane between extracellular ligands and the actin cytoskeleton. In activation of the transforming growth factor-beta1 precursor (pro-TGF-beta1), integrins bind to the prodomain, apply force, and release the TGF-beta growth factor. However, we know little about how integrins bind macromolecular ligands in the extracellular matrix or transmit force to them. Here we show how integrin alphaVbeta6 binds pro-TGF-beta1 in an orientation biologically relevant for force-dependent release of TGF-beta from latency. The conformation of the prodomain integrin-binding motif differs in the presence and absence of integrin binding; differences extend well outside the interface and illustrate how integrins can remodel extracellular matrix. Remodelled residues outside the interface stabilize the integrin-bound conformation, adopt a conformation similar to earlier-evolving family members, and show how macromolecular components outside the binding motif contribute to integrin recognition. Regions in and outside the highly interdigitated interface stabilize a specific integrin/pro-TGF-beta orientation that defines the pathway through these macromolecules which actin-cytoskeleton-generated tensile force takes when applied through the integrin beta-subunit. Simulations of force-dependent activation of TGF-beta demonstrate evolutionary specializations for force application through the TGF-beta prodomain and through the beta- and not alpha-subunit of the integrin. Force interacts with macromolecular structure in activation of TGF-beta.,Dong X, Zhao B, Iacob RE, Zhu J, Koksal AC, Lu C, Engen JR, Springer TA Nature. 2017 Feb 2;542(7639):55-59. doi: 10.1038/nature21035. Epub 2017 Jan 25. PMID:28117447[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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