Integrin alphaIIb beta3:p(Y530)-SRC:CSK:Talin:RIAM complex Focal complex Integrin alphaIIb beta3 ECM ligands Interaction of integrin alphaIIb beta3 with Fibrinogen Authored: Garapati, P V, 2008-06-16 17:13:06 Edited: Garapati, P V, 2008-06-16 17:13:06 Pubmed10446041 Pubmed10508650 Pubmed11468358 Pubmed14754902 Pubmed16040750 Reactome Database ID Release 43354149 Reactome, http://www.reactome.org ReactomeREACT_15500 Reviewed: Shattil, SJ, 2008-09-16 06:21:39 The overall shape of integrins is that of a globular 'head' supported by two rod like legs. The ligand-binding pocket is formed by the combination of A-domain or beta-I domain on the beta3 subunit and the putative beta-propeller fold on the alphaIIb subunit in the head regions. The binding of ligand to integrin is also dependent on divalent cations (usually Mn++ or Mg++or Ca++). A conserved motif, the metal ion-dependant adhesion site (MIDAS) is located in the alpha and the beta chains that coordinate the divalent cation at the top of the domain. <br>Active integrin alphaIIb beta3 interacts with a variety of plasma proteins such as fibrinogen, vWF, thrombin, thrombospondin, and fibronectin. The ability of alphaIIbbeta3 to bind fibrinogen plays a crucial role in platelet aggregation and hemostasis. Most of these matrix proteins have integrin binding sites of 3-6 amino acids length, of which the best known are the 'RGD' and 'KGD' motifs. The alpha and beta integrin subunits are both required for ligand binding. Integrin binding divalent cations