ID:GP1BA_HUMAN DESCRIPTION: RecName: Full=Platelet glycoprotein Ib alpha chain; Short=GP-Ib alpha; Short=GPIb-alpha; Short=GPIbA; Short=Glycoprotein Ibalpha; AltName: Full=Antigen CD42b-alpha; AltName: CD_antigen=CD42b; Contains: RecName: Full=Glycocalicin; Flags: Precursor; FUNCTION: GP-Ib, a surface membrane protein of platelets, participates in the formation of platelet plugs by binding to the A1 domain of vWF, which is already bound to the subendothelium. SUBUNIT: Two GP-Ib beta are disulfide-linked to one GP-Ib alpha. GP-IX is complexed with the GP-Ib heterodimer via a non covalent linkage. Interacts with FLNB. INTERACTION: P04275:VWF; NbExp=2; IntAct=EBI-297082, EBI-981819; SUBCELLULAR LOCATION: Membrane; Single-pass type I membrane protein. PTM: Glycocalicin, which is approximately coextensive with the extracellular part of the molecule, is cleaved off by calpain during platelet lysis. POLYMORPHISM: Position 161 is associated with platelet-specific alloantigen Siba. Siba(-) has Thr-161 and Siba(+) has Met-161. Siba is involved in neonatal alloimmune thrombocytopenia (NATP). POLYMORPHISM: Polymorphisms arise from a variable number of tandem 13-amino acid repeats of S-E-P-A-P-S-P-T-T-P-E-P-T in the mucin- like macroglycopeptide (Pro/Thr-rich) domain. Allele D (shown here) contains one repeat starting at position 415, allele C contains two repeats, allele B contains three repeats and allele A contains four repeats. Allele B is associated with susceptibility to nonarteritic anterior ischemic optic neuropathy. DISEASE: Genetic variations in GP1BA may be a cause of susceptibility to non-arteritic anterior ischemic optic neuropathy (NAION) [MIM:258660]. NAION is an ocular disease due to ischemic injury to the optic nerve. It usually affects the optic disk and leads to visual loss and optic disk swelling of a pallid nature. Visual loss is usually sudden, or over a few days at most and is usually permanent, with some recovery possibly occurring within the first weeks or months. Patients with small disks having smaller or non-existent cups have an anatomical predisposition for non-arteritic anterior ischemic optic neuropathy. As an ischemic episode evolves, the swelling compromises circulation, with a spiral of ischemia resulting in further neuronal damage. DISEASE: Defects in GP1BA are a cause of Bernard-Soulier syndrome (BSS) [MIM:231200]; also known as giant platelet disease (GPD). BSS patients have unusually large platelets and have a clinical bleeding tendency. DISEASE: Defects in GP1BA are the cause of benign mediterranean macrothrombocytopenia (BMM) [MIM:153670]; also known as autosomal dominant benign Bernard-Soulier syndrome. BMM is characterized by mild or no clinical symptoms, normal platelet function, and normal megakaryocyte count. DISEASE: Defects in GP1BA are the cause of pseudo-von Willebrand disease (VWDP) [MIM:177820]. A bleeding disorder is caused by an increased affinity of GP-Ib for soluble vWF resulting in impaired hemostatic function due to the removal of vWF from the circulation. MISCELLANEOUS: Platelet activation apparently involves disruption of the macromolecular complex of GP-Ib with the platelet glycoprotein IX (GP-IX) and dissociation of GP-Ib from the actin- binding protein. MISCELLANEOUS: Binding sites for vWF and thrombin (the latter site with unknown function) are in the N-terminal part of the molecule. SIMILARITY: Contains 7 LRR (leucine-rich) repeats. SIMILARITY: Contains 1 LRRCT domain. SIMILARITY: Contains 1 LRRNT domain. WEB RESOURCE: Name=GeneReviews; URL="http://www.ncbi.nlm.nih.gov/sites/GeneTests/lab/gene/GP1BA"; WEB RESOURCE: Name=SeattleSNPs; URL="http://pga.gs.washington.edu/data/gp1ba/";
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
ModBase Predicted Comparative 3D Structure on P07359
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
US Server
Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
