GP1BA

(redirected from GPIbA)

GP1BA

A gene on chromosome 17pter-p12 that encodes the alpha subunit of the Ib-V-IX system of platelet surface membrane glycoproteins, which comprise the von Willebrand factor (vWF) receptor and mediate adhesion of platelets to injured vascular surfaces with circulation, a critical event in haemostasis. The alpha subunit provides the vWF binding site.

Molecular pathology
GP1BA polymorphisms and mutations are linked to Bernard-Soulier syndromes and platelet-type von Willebrand disease.
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References in periodicals archive ?
GPIb[alpha], GPIb[beta] and GPIX, encoded by the GPIBA, GP1BB and GP9 genes, are all required for efficient expression of the complex on the platelet surface, while absence of GPV does not appear to affect receptor expression or VWF binding.
Some experts have demonstrated that genetic polymorphisms of platelet membrane glycoproteins (GPI1, GPIba, GPIIIa, and GPIV) may influence the efficacy of aspirin or platelet responsiveness, and genetic polymorphisms of the thromboxane A2 receptor (TBXA2R), platelet-activating factor acetylhydrolase, and coagulation factor XIII were associated with platelet aggregation.
Since GPIba mainly influences platelet aggregation, we may evaluate the platelet aggregation ability between different genotypes to understand better the mechanisms involved.
PT-VWD can be diagnosed only by specialized testing (ristocetin-induced platelet aggregation mixing studies) and genetic testing of GPIBA (glycoprotein Ib (platelet), alpha polypeptide).
Recombinant human GPIba (RandD) was used as the antigen in assay detecting B cells producing IgG anti-GPIb antibodies.
Relative efficacy of steroid therapy in immune thrombocytopenia mediated by anti-platelet GPIIbIIIa versus GPIba antibodies.
Part of the GPIba receptors may be occupied by soluble vWF and unable to interact with vWF immobilized on the tissues exposed at the sites of injury.
Thrombocytopenia may be present due to enhanced ability of vWFto bind platelet receptor GPIbA, causing removal of the platelet/vWF complex.
La glicoproteina de membrana GPIba (llamada complejo GPIb/V/IX) constituiria el factor de adhesion entre plaquetas y el dominio A1 del factor Von Willebrand multimerico de alto peso molecular, determinando junto con otras moleculas intercurrentes la agregacion plaquetaria posterior al dano endotelial.
Platelet treatment with mocarhagin, a cobra venom metalloproteinase that cleaves GpIba, significantly reduced aggregation induced by 5 mM without affecting the response to other agonists such as adenosine diphosphate (ADP).
Most of the genetic defects are due to mutations of the GPIba gene, but may also be due to defects of the GPIbI3 or GPIX genes.