Glycoprotein Ib (platelet), beta polypeptide (GP1BB) also known asCD42c (Cluster ofDifferentiation42c), is a protein that in humans is encoded by the GP1BB gene.[5]
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 theGlycoprotein Ib-IX-V Receptor Complex (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 withBernard–Soulier syndrome,velocardiofacial syndrome andgiant 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 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.[5]
Andrews RK, Booth WJ, Gorman JJ, Castaldi PA, Berndt MC (1989). "Purification of botrocetin from Bothrops jararaca venom. Analysis of the botrocetin-mediated interaction between von Willebrand factor and the human platelet membrane glycoprotein Ib-IX complex".Biochemistry.28 (21):8317–26.doi:10.1021/bi00447a009.PMID2557900.
Berndt MC, Gregory C, Kabral A, Zola H, Fournier D, Castaldi PA (1985). "Purification and preliminary characterization of the glycoprotein Ib complex in the human platelet membrane".Eur. J. Biochem.151 (3):637–49.doi:10.1111/j.1432-1033.1985.tb09152.x.PMID3161731.
Andrews RK, Harris SJ, McNally T, Berndt MC (1998). "Binding of purified 14-3-3 zeta signaling protein to discrete amino acid sequences within the cytoplasmic domain of the platelet membrane glycoprotein Ib-IX-V complex".Biochemistry.37 (2):638–47.doi:10.1021/bi970893g.PMID9425086.
Longhurst CM, White MM, Wilkinson DA, Jennings LK (1999). "A CD9, alphaIIbbeta3, integrin-associated protein, and GPIb/V/IX complex on the surface of human platelets is influenced by alphaIIbbeta3 conformational states".Eur. J. Biochem.263 (1):104–11.doi:10.1046/j.1432-1327.1999.00467.x.PMID10429193.
Feng S, Christodoulides N, Reséndiz JC, Berndt MC, Kroll MH (2000). "Cytoplasmic domains of GpIbalpha and GpIbbeta regulate 14-3-3zeta binding to GpIb/IX/V".Blood.95 (2):551–7.doi:10.1182/blood.V95.2.551.PMID10627461.S2CID77799615.
Moran N, Morateck PA, Deering A, Ryan M, Montgomery RR, Fitzgerald DJ, Kenny D (2000). "Surface expression of glycoprotein ib alpha is dependent on glycoprotein ib beta: evidence from a novel mutation causing Bernard-Soulier syndrome".Blood.96 (2):532–9.doi:10.1182/blood.V96.2.532.PMID10887115.
