Glycoprotein Ib (platelet), beta polypeptide (GP1BB) also known as CD42c (Cluster of Differentiation 42c), is a protein that in humans is encoded by the GP1BB gene.
Function
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
Glycoprotein Ib-IX-V Receptor Complex
The GPIb-IX-V complex is a profuse membrane Cell surface receptor, receptor complex originating in megakaryocytes and exclusively functional on the surface of platelets. It primarily functions to mediate the first critical step in platelet adhesion ...
(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
Bernard–Soulier syndrome (BSS) is a rare autosomal recessive bleeding disorder that is caused by a deficiency of the '' glycoprotein Ib-IX-V complex'' (GPIb-IX-V), the receptor for von Willebrand factor. The incidence of BSS is estimated to be ...
,
velocardiofacial syndrome and
giant platelet disorder
Giant platelet disorders, also known as macrothrombocytopenia, are rare disorders featuring abnormally large platelets, thrombocytopenia and a tendency to bleeding. Giant platelets cannot stick adequately to injured blood vessel walls, resulting i ...
. 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 within a separate gene (septin 5) located upstream of this gene. In the absence of polyadenylation from its own imperfect site, the septin 5 gene uses the consensus polyA signal of this gene.
Interactions
GP1BB has been shown to
interact with
YWHAZ
14-3-3 protein zeta/delta (14-3-3ζ) is a protein that in humans is encoded by the ''YWHAZ'' gene on chromosome 8. The protein encoded by this gene is a member of the 14-3-3 protein family and a central hub protein for many signal transduction p ...
.
See also
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Cluster of differentiation
The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophe ...
References
Further reading
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External links
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PDBe-KBprovides an overview of all the structure information available in the PDB for Human Platelet glycoprotein Ib beta chain (GP1BB)
{{Coagulation
Clusters of differentiation