ITGB3

Integrin beta-3 ;
Platelet membrane glycoprotein IIIa ;
GPIIIa ;
CD antigen CD61 ;

disease:Defects in ITGB3 are a cause of Glanzmann thrombasthenia (GT) [MIM:273800]; also known as thrombasthenia of Glanzmann and Naegeli. GT is the most common inherited disease of platelets. Its inheritance is autosomal recessive. It is characterized by mucocutaneous bleeding of mild-to-moderate severity and the inability of this integrin to recognize macromolecular or synthetic peptide ligands. GT has been classified clinically into types I and II. In type I , platelets show absence of the glycoprotein IIb-IIIa complexes at their surface and lack fibrinogen and clot retraction capability. In type II , the platelets express the GPIIb-IIIa complex at reduced levels (5-20% controls) , have detectable amounts of fibrinogen , and have low or moderate clot retraction capability. The platelets of GT variants have normal or near normal (60-100%) expression of dysfunctional receptors. ,function:Integrin alpha-V/beta-3 is a receptor for cytotactin , fibronectin , laminin , matrix metalloproteinase-2 , osteopontin , osteomodulin , prothrombin , thrombospondin , vitronectin and von Willebrand factor. Integrin alpha-IIb/beta-3 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 surface. In case of HIV-1 infection , the interaction with extracellular viral Tat protein seems to enhance angiogenesis in Kaposi's sarcoma lesions. ,online information:The Singapore human mutation and polymorphism database ,polymorphism:Position 169 is associated with platelet-specific alloantigen HPA-4 (PEN or YUK) . HPA-4A/PEN (A) /YUK (A) has Arg-169 and HPA-4B/PEN (B) /YUK (B) has Gln-169. HPA-4B is involved in neonatal alloimmune thrombocytopenia (NAIT or NATP) . ,polymorphism:Position 433 is associated with platelet-specific alloantigen MO. MO (-) has Pro-433 and MO (+) has Ala-433. MO (+) is involved in NAIT. ,polymorphism:Position 515 is associated with platelet-specific alloantigen CA/TU. CA (-) /TU (-) has Arg-515 and CA (+) /TU (+) has Gln-515. CA (+) is involved in NAIT. ,polymorphism:Position 59 is associated with platelet-specific alloantigen HPA-1 (ZW or PL (A) ) . HPA-1A/ZW (A) /PL (A1) has Leu-59 and HPA-1B/ZW (B) /PL (A2) has Pro-59. ,polymorphism:Position 662 is associated with platelet-specific alloantigen SR (A) . SR (A) (-) has Arg-662 and SR (A) (+) has Cys-662. ,PTM:Phosphorylated on tyrosine residues in response to thrombin-induced platelet aggregation. Probably involved in outside-in signaling. A peptide (AA 740-762) is capable of binding GRB2 only when both Tyr-773 and Tyr-785 are phosphorylated. Phosphorylation of Thr-779 inhibits SHC binding. ,similarity:Belongs to the integrin beta chain family. ,similarity:Contains 1 VWFA domain. ,subunit:Heterodimer of an alpha and a beta subunit. Beta-3 associates with either alpha-IIb or alpha-V. Isoform Beta-3C interacts with FLNB. Interacts with HIV-1 Tat. ,tissue specificity:Isoform beta-3A and isoform beta-3C are widely expressed. Isoform beta-3A is specifically expressed in osteoblast cells; isoform beta-3C is specifically expressed in prostate and testis. ,

cell-substrate junction assembly , cell adhesion , cell-matrix adhesion , cell surface receptor linked signal transduction ,integrin-mediated signaling pathway , blood coagulation , hemostasis , response to wounding , negative regulation of biosynthetic process , negative regulation of macromolecule biosynthetic process , negative regulation of macromolecule metabolic process , regulation of foam cell differentiation , negative regulation of foam cell differentiation , regulation of receptor biosynthetic process , negative regulation of receptor biosynthetic process ,regulation of lipid storage , negative regulation of lipid storage , biological adhesion , regulation of cell migration , cell-substrate adhesion , regulation of cellular protein metabolic process , negative regulation of cellular protein metabolic process , regulation of lipid transport , negative regulation of lipid transport , cell junction assembly , cell junction organization , regulation of locomotion , wound healing , negative regulation of cell differentiation , regulation of low-density lipoprotein receptor biosynthetic process , negative regulation of low-density lipoprotein receptor biosynthetic process , regulation of lipoprotein metabolic process , negative regulation of lipoprotein metabolic process , coagulation ,regulation of body fluid levels , negative regulation of transport , negative regulation of protein metabolic process ,regulation of cell motion ,

Cell membrane ; Single-pass type I membrane protein . Cell projection , lamellipodium membrane . Cell junction , focal adhesion . Cell junction , synapse , postsynaptic cell membrane ; Single-pass type I membrane protein . Cell junction , synapse .