5xq1

Structural highlights

Function

FERM2_MOUSE Scaffolding protein that enhances integrin activation mediated by TLN1 and/or TLN2, but activates integrins only weakly by itself. Binds to membranes enriched in phosphoinositides. Enhances integrin-mediated cell adhesion onto the extracellular matrix and cell spreading; this requires both its ability to interact with integrins and with phospholipid membranes. Required for the assembly of focal adhesions. Participates in the connection between extracellular matrix adhesion sites and the actin cytoskeleton and also in the orchestration of actin assembly and cell shape modulation. Recruits FBLIM1 to focal adhesions. Plays a role in the TGFB1 and integrin signaling pathways. Stabilizes active CTNNB1 and plays a role in the regulation of transcription mediated by CTNNB1 and TCF7L2/TCF4 and in Wnt signaling.^{[1] [2] [3]} ITB3_MOUSE Integrin alpha-V/beta-3 (ITGAV:ITGB3) is a receptor for cytotactin, fibronectin, laminin, matrix metalloproteinase-2, osteopontin, osteomodulin, prothrombin, thrombospondin, vitronectin and von Willebrand factor. Integrin alpha-IIB/beta-3 (ITGA2B:ITGB3) is a receptor for fibronectin, fibrinogen, plasminogen, prothrombin, thrombospondin and vitronectin. Integrins alpha-IIB/beta-3 and alpha-V/beta-3 recognize the sequence R-G-D in a wide array of ligands. Integrin alpha-IIB/beta-3 recognizes the sequence H-H-L-G-G-G-A-K-Q-A-G-D-V in fibrinogen gamma chain. Following activation integrin alpha-IIB/beta-3 brings about platelet/platelet interaction through binding of soluble fibrinogen. This step leads to rapid platelet aggregation which physically plugs ruptured endothelial surfaces. Fibrinogen binding enhances SELP expression in activated platelets (PubMed:19332769). ITGAV:ITGB3 binds to fractalkine (CX3CL1) and acts as its coreceptor in CX3CR1-dependent fractalkine signaling. ITGAV:ITGB3 binds to NRG1 (via EGF domain) and this binding is essential for NRG1-ERBB signaling. ITGAV:ITGB3 binds to FGF1 and this binding is essential for FGF1 signaling. ITGAV:ITGB3 binds to FGF2 and this binding is essential for FGF2 signaling (By similarity). ITGAV:ITGB3 binds to IGF1 and this binding is essential for IGF1 signaling (By similarity). ITGAV:ITGB3 binds to IGF2 and this binding is essential for IGF2 signaling (By similarity). ITGAV:ITGB3 binds to IL1B and this binding is essential for IL1B signaling (By similarity). ITGAV:ITGB3 binds to PLA2G2A via a site (site 2) which is distinct from the classical ligand-binding site (site 1) and this induces integrin conformational changes and enhanced ligand binding to site 1 (By similarity). ITGAV:ITGB3 acts as a receptor for fibrillin-1 (FBN1) and mediates R-G-D-dependent cell adhesion to FBN1 (By similarity). In brain, plays a role in synaptic transmission and plasticity (PubMed:29038237, PubMed:18549786). Involved in the regulation of the serotonin neurotransmission, is required to localize to specific compartments within the synapse the serotonin receptor SLC6A4 and for an appropriate reuptake of serotonin (PubMed:29038237). Controls excitatory synaptic strength by regulating GRIA2-containing AMPAR endocytosis, which affects AMPAR abundance and composition (PubMed:18549786). ITGAV:ITGB3 act as a receptor for CD40LG (By similarity).[UniProtKB:P05106]^{[4] [5] [6]}

References

1. ↑ Dowling JJ, Gibbs E, Russell M, Goldman D, Minarcik J, Golden JA, Feldman EL. Kindlin-2 is an essential component of intercalated discs and is required for vertebrate cardiac structure and function. Circ Res. 2008 Feb 29;102(4):423-31. doi: 10.1161/CIRCRESAHA.107.161489. Epub, 2008 Jan 3. PMID:18174465 doi:http://dx.doi.org/10.1161/CIRCRESAHA.107.161489
2. ↑ Montanez E, Ussar S, Schifferer M, Bosl M, Zent R, Moser M, Fassler R. Kindlin-2 controls bidirectional signaling of integrins. Genes Dev. 2008 May 15;22(10):1325-30. doi: 10.1101/gad.469408. PMID:18483218 doi:http://dx.doi.org/10.1101/gad.469408
3. ↑ Pluskota E, Dowling JJ, Gordon N, Golden JA, Szpak D, West XZ, Nestor C, Ma YQ, Bialkowska K, Byzova T, Plow EF. The integrin coactivator kindlin-2 plays a critical role in angiogenesis in mice and zebrafish. Blood. 2011 May 5;117(18):4978-87. doi: 10.1182/blood-2010-11-321182. Epub 2011, Mar 4. PMID:21378273 doi:http://dx.doi.org/10.1182/blood-2010-11-321182
4. ↑ Cingolani LA, Thalhammer A, Yu LM, Catalano M, Ramos T, Colicos MA, Goda Y. Activity-dependent regulation of synaptic AMPA receptor composition and abundance by beta3 integrins. Neuron. 2008 Jun 12;58(5):749-62. doi: 10.1016/j.neuron.2008.04.011. PMID:18549786 doi:http://dx.doi.org/10.1016/j.neuron.2008.04.011
5. ↑ Yang H, Lang S, Zhai Z, Li L, Kahr WH, Chen P, Brkic J, Spring CM, Flick MJ, Degen JL, Freedman J, Ni H. Fibrinogen is required for maintenance of platelet intracellular and cell-surface P-selectin expression. Blood. 2009 Jul 9;114(2):425-36. doi: 10.1182/blood-2008-03-145821. Epub 2009 Mar, 30. PMID:19332769 doi:http://dx.doi.org/10.1182/blood-2008-03-145821
6. ↑ Dohn MR, Kooker CG, Bastarache L, Jessen T, Rinaldi C, Varney S, Mazalouskas MD, Pan H, Oliver KH, Velez Edwards DR, Sutcliffe JS, Denny JC, Carneiro AMD. The Gain-of-Function Integrin beta3 Pro33 Variant Alters the Serotonin System in the Mouse Brain. J Neurosci. 2017 Nov 15;37(46):11271-11284. doi: 10.1523/JNEUROSCI.1482-17.2017. , Epub 2017 Oct 16. PMID:29038237 doi:http://dx.doi.org/10.1523/JNEUROSCI.1482-17.2017
7. ↑ Li H, Deng Y, Sun K, Yang H, Liu J, Wang M, Zhang Z, Lin J, Wu C, Wei Z, Yu C. Structural basis of kindlin-mediated integrin recognition and activation. Proc Natl Acad Sci U S A. 2017 Jul 24. pii: 201703064. doi:, 10.1073/pnas.1703064114. PMID:28739949 doi:http://dx.doi.org/10.1073/pnas.1703064114