GP1BB Gene - Glycoprotein Ib Platelet Beta Subunit
Essential Component of the Platelet Glycoprotein Ib-IX-V Receptor Complex
Gene Information Card
| Symbol | GP1BB |
|---|---|
| Full Name | Glycoprotein Ib Platelet Beta Subunit |
| Gene Type | Protein coding |
| Chromosomal Location | 22q11.21 |
| NCBI Gene ID | 2812 ncbi.nlm.nih.gov/gene/2812 |
| Ensembl ID | ENSG00000100219 |
| UniProt ID | P13224 |
| OMIM ID | 138720 |
| HGNC ID | 4440 |
| Aliases | CD42c, GPIb beta, GPIbB |
Description
The GP1BB gene encodes the beta subunit of glycoprotein Ib (GPIb), a component of the platelet glycoprotein Ib-IX-V receptor complex. This complex is essential for platelet adhesion to exposed subendothelial von Willebrand factor (vWF) at sites of vascular injury, initiating hemostatic plug formation. GP1BB is primarily expressed in megakaryocytes and platelets. Mutations in GP1BB cause Bernard-Soulier syndrome (BSS), an autosomal recessive bleeding disorder characterized by thrombocytopenia, giant platelets, and defective platelet adhesion.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Bernard-Soulier syndrome (BSS) | Loss-of-function mutations in GP1BB disrupt the GPIb-IX-V complex, impairing vWF binding and platelet adhesion, leading to bleeding tendency. | ClinVar, OMIM |
| Giant platelet disorder | Defective GP1BB results in abnormal megakaryocyte maturation and large, dysfunctional platelets. | OMIM |
| Thrombocytopenia | Reduced platelet count due to impaired platelet production or survival associated with GP1BB mutations. | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Whole blood | 0.0 | Not detected |
| Bone marrow | 0.0 | Not detected |
| Spleen | 0.0 | Not detected |
| Lung | 0.0 | Not detected |
| Platelets (isolated) | High (specific) | High expression in megakaryocytes and platelets |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Megakaryocytes | High | Primary site of GP1BB expression |
| Platelets | High | Surface expression of GPIb-IX-V complex |
| HEK293 | Low | Not endogenous; used in recombinant studies |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Loss of start codon, no protein synthesis |
| c.122G>A (p.Cys41Tyr) | Missense | Rare | Disrupts disulfide bond, complex instability |
| c.233delC (p.Pro78fs) | Frameshift | Rare | Premature truncation, loss of function |
| c.340C>T (p.Arg114*) | Nonsense | Rare | Nonsense-mediated decay, absent protein |
Mutation functional classification
Loss of Function (LOF)
Most GP1BB mutations are loss-of-function, leading to reduced or absent GPIb beta protein, impairing receptor complex assembly and vWF binding.
Gain of Function (GOF)
No gain-of-function mutations reported for GP1BB.
Dominant Negative (DN)
Rare heterozygous missense mutations may exert dominant-negative effects by disrupting complex assembly, though BSS is typically autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • protein binding (GO:0005515) | • plasma membrane (GO:0005886) |
| • blood coagulation (GO:0007596) | • integral component of membrane (GO:0016021) |
| • von Willebrand factor binding (GO:0031594) | • extracellular exosome (GO:0070062) |
Pathways
• Platelet adhesion to exposed collagen (Reactome: R-HSA-76009)
• GP1b-IX-V activation signalling (Reactome: R-HSA-430116)
• Hemostasis (Reactome: R-HSA-109582)
Protein Summary
The GP1BB protein (GPIb beta) is a 206-amino acid transmembrane glycoprotein that forms a disulfide-linked heterodimer with GPIb alpha. This dimer associates non-covalently with GPIX and GPV to form the GPIb-IX-V complex on platelet surfaces. The cytoplasmic tail of GPIb beta contains a binding site for the actin-binding protein filamin A, linking the receptor to the cytoskeleton. GPIb beta is essential for receptor stability and surface expression. Defects in GP1BB cause Bernard-Soulier syndrome, a rare bleeding disorder.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GP1BB Knockout HEK293 Cell Line | EDJ-KQ2944 | Human | 2812 | Details Get a Quote |
| GP1BB Knockout HeLa Cell Line | EDJ-KQ53377 | Human | 2812 | Details Get a Quote |
| GP1BB Knockout A-549 Cell Line | EDJ-KQ61853 | Human | 2812 | Details Get a Quote |
| GP1BB Knockout HCT 116 Cell Line | EDJ-KQ70338 | Human | 2812 | Details Get a Quote |
