Entrez Summary: 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].
UniProt Summary: 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.
Pfam DomainsGO Terms
Pfam Domains
No Pfam Domain information is available for this gene.
GO Terms
blood coagulation, intrinsic pathway
blood coagulation, fibrin clot formation
protein activation cascade
transmembrane signaling receptor activity
platelet activation
blood coagulation
coagulation
hemostasis
wound healing
regulation of body fluid levels
response to wounding
cell adhesion
biological adhesion
identical protein binding
cell activation
integral component of plasma membrane
CRISPR Data
Compound HitMost Correlated Genes in ChemogenomicsTissues where Essential in the Avana Dataset (DepMap 20Q1)