Platelet Glycoprotein Ib Beta Chain (GP1BB) ELISA Kit for Human

Platelet glycoprotein Ib (GPIb) is a heterodimeric transmembrane protein consisting of a disulfide-linked 140 kD alpha chain and 22 kD beta chain. It is part of the GPIb-V-IX system that constitutes the receptor for von Willebrand factor (VWF), and mediates platelet adhesion in the arterial circulation. GPIb alpha chain provides the VWF binding site, and GPIb beta contributes to surface expression of the receptor and participates in transmembrane signaling through phosphorylation of its intracellular domain. Mutations in the GPIb beta subunit have been associated with Bernard-Soulier syndrome, velocardiofacial syndrome and giant platelet disorder. The 206 amino acid precursor of GPIb beta is synthesized from a 1.0 kb mRNA expressed in plateletes and megakaryocytes. A 411 amino acid protein arising from a longer, unspliced transcript in endothelial cells has been described; however, the authenticity of this product has been questioned. Yet another less abundant GPIb beta mRNA species of 3.5 kb, expressed in nonhematopoietic tissues such as endothelium, brain and heart, was shown to result from inefficient usage of a non-consensus polyA signal in the neighboring upstream gene (SEPT5, septin 5). In the absence of polyadenylation from its own imperfect site, the SEPT5 gene produces read-through transcripts that use the consensus polyA signal of this gene. [provided by RefSeq, Dec 2010]

GPIbB: Gp-Ib, a surface membrane protein of platelets, participates in the formation of platelet plugs by binding to von Willebrand factor, which is already bound to the subendothelium. Defects in GP1BB are a cause of Bernard-Soulier syndrome (BSS); also known as giant platelet disease (GPD). BSS patients have unusually large platelets and have a clinical bleeding tendency. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Cell surface; Membrane protein, integral

Chromosomal Location of Human Ortholog: 22q11.21

Cellular Component: integral component of plasma membrane; plasma membrane

Molecular Function: identical protein binding; protein binding; transmembrane receptor activity

Biological Process: blood coagulation; blood coagulation, intrinsic pathway; cell adhesion; cell surface receptor signaling pathway; platelet activation

Disease: Bernard-soulier Syndrome