GP1BA: Glycoprotein Ib Platelet Alpha Subunit
Key regulator of platelet adhesion and thrombus formation
Gene Information Card
| Symbol | GP1BA |
|---|---|
| Full Name | Glycoprotein Ib Platelet Alpha Subunit |
| Gene Type | Protein coding |
| Chromosomal Location | 17p13.2 |
| NCBI Gene ID | 2811 ncbi.nlm.nih.gov/gene/2811 |
| Ensembl ID | ENSG00000185245 |
| UniProt ID | P07359 |
| OMIM ID | 606672 |
| HGNC ID | 4439 |
| Aliases | GPIbA, BSS, GPIb-alpha, CD42b-alpha, VWDP |
Description
GP1BA encodes the alpha subunit of platelet glycoprotein Ib (GPIb), a major component of the von Willebrand factor (vWF) receptor complex on the platelet surface. This receptor mediates platelet adhesion to injured vascular endothelium and is critical for primary hemostasis. Mutations in GP1BA cause Bernard-Soulier syndrome (BSS), a bleeding disorder characterized by macrothrombocytopenia and defective platelet adhesion.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Bernard-Soulier syndrome | Loss-of-function mutations in GP1BA impair GPIb-IX-V complex assembly or vWF binding, leading to defective platelet adhesion and giant platelets. | ClinVar, OMIM |
| Platelet-type von Willebrand disease | Gain-of-function mutations increase affinity for vWF, causing spontaneous platelet aggregation and mild thrombocytopenia. | ClinVar, OMIM |
| Isolated macrothrombocytopenia | Heterozygous missense variants in GP1BA can cause mild thrombocytopenia with large platelets without severe bleeding. | NCBI, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Whole blood | 12.5 | High |
| Bone marrow | 8.3 | Medium |
| Spleen | 3.1 | Low |
| Lung | 1.2 | Low |
| Liver | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Megakaryocytes | 45.2 | High expression |
| Platelets | 38.7 | High expression |
| HEL (erythroleukemia) | 22.1 | Moderate expression |
| K562 (chronic myeloid leukemia) | 5.4 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.101C>T (p.Thr34Met) | Missense | Rare | Gain-of-function; increased vWF binding; associated with platelet-type vWD |
| c.130G>A (p.Val44Met) | Missense | Rare | Loss-of-function; disrupts GPIb-IX complex; causes Bernard-Soulier syndrome |
| c.515C>T (p.Pro172Leu) | Missense | Rare | Loss-of-function; impairs vWF binding; BSS phenotype |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss-of-function; no protein expression; severe BSS |
Mutation functional classification
Loss of Function (LOF)
Mutations that disrupt GPIb-IX-V complex assembly, reduce surface expression, or impair vWF binding lead to Bernard-Soulier syndrome (autosomal recessive).
Gain of Function (GOF)
Missense variants that increase affinity for vWF cause platelet-type von Willebrand disease (autosomal dominant), with enhanced platelet aggregation and thrombocytopenia.
Dominant Negative (DN)
Some heterozygous missense mutations in the extracellular domain can interfere with wild-type GPIb function, contributing to mild macrothrombocytopenia.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Platelet adhesion to exposed collagen (Reactome R-HSA-76009)
• GP1b-IX-V activation signalling (Reactome R-HSA-430116)
• Platelet activation
• signaling and aggregation (KEGG hsa04611)
Protein Summary
The GP1BA protein (610 amino acids, ~145 kDa) is a type I transmembrane glycoprotein with a large extracellular N-terminal domain containing leucine-rich repeats that bind von Willebrand factor. It forms a non-covalent complex with GP1BB, GP9, and GP5 to constitute the GPIb-IX-V receptor. The cytoplasmic tail interacts with filamin A and the cytoskeleton, anchoring the receptor to the platelet membrane. Post-translational glycosylation is essential for proper folding and function.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GP1BA Knockout HEK293 Cell Line | EDJ-KQ50309 | Human | 2811 | Details Get a Quote |
| GP1BA Knockout HeLa Cell Line | EDJ-KQ53376 | Human | 2811 | Details Get a Quote |
| GP1BA Knockout A-549 Cell Line | EDJ-KQ61852 | Human | 2811 | Details Get a Quote |
| GP1BA Knockout HCT 116 Cell Line | EDJ-KQ70337 | Human | 2811 | Details Get a Quote |
