STXBP5
Syntaxin Binding Protein 5 (Tomosyn)
Gene Information Card
| Symbol | STXBP5 |
|---|---|
| Full Name | Syntaxin Binding Protein 5 |
| Gene Type | Protein coding |
| Chromosomal Location | 6q24.3 |
| NCBI Gene ID | 134957 ncbi.nlm.nih.gov/gene/134957 |
| Ensembl ID | ENSG00000112210 |
| UniProt ID | Q5T5C0 |
| OMIM ID | 604309 |
| HGNC ID | 11457 |
| Aliases | tomosyn, LGL3, LLGL3, Nbla04380, bA479K20.2 |
Description
STXBP5 encodes tomosyn, a cytosolic protein that binds syntaxin-1A and negatively regulates SNARE complex assembly, thereby modulating exocytosis of secretory vesicles. It is highly expressed in platelets, brain, and endocrine tissues. Genetic variants in STXBP5 have been associated with altered platelet function, bleeding risk, and venous thromboembolism.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Bleeding disorder, platelet-type 20 (BDPLT20) | Loss-of-function variants impair tomosyn-mediated inhibition of SNARE complex, leading to enhanced platelet granule secretion and defective hemostasis. | ClinVar, OMIM #616913 |
| Venous thromboembolism | GWAS-identified intronic variants (e.g., rs1039084) associated with increased risk, possibly through altered platelet reactivity. | PMID: 19587359, GWAS catalog |
| Thrombocytopenia | Rare missense variants may disrupt platelet production or survival. | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Whole blood | 12.4 | Medium |
| Brain (cerebellum) | 8.7 | Medium |
| Brain (cortex) | 7.2 | Medium |
| Pancreas | 6.5 | Medium |
| Adrenal gland | 5.9 | Low |
| Lung | 3.1 | Low |
| Liver | 1.2 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 9.8 | Moderate expression |
| SH-SY5Y | 11.2 | Neuronal model, high expression |
| MEG-01 | 14.5 | Megakaryocytic cell line, high expression |
| K562 | 6.3 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.2932C>T (p.Arg978*) | Nonsense | <0.01% | Loss of function; associated with BDPLT20 |
| c.1246G>A (p.Gly416Arg) | Missense | <0.01% | Likely damaging; reported in thrombocytopenia |
| rs1039084 (intronic) | SNP | 30-40% (European) | Risk allele for venous thromboembolism |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift variants that truncate tomosyn, reducing inhibition of SNARE-mediated exocytosis, leading to enhanced platelet secretion and bleeding.
Gain of Function (GOF)
Not described in literature.
Dominant Negative (DN)
Not described in literature.
View complete mutation data：
Gene Ontology (GO)
| • syntaxin binding (GO:0019905) | • exocytosis (GO:0006887) |
| • vesicle docking (GO:0048278) | • SNARE complex (GO:0031201) |
| • protein binding (GO:0005515) | • cytoplasm (GO:0005737) |
Pathways
• SNARE interactions in vesicular transport (Reactome: R-HSA-421837)
• Platelet degranulation (Reactome: R-HSA-114608)
• Exocytosis (Reactome: R-HSA-6798695)
Protein Summary
Tomosyn (STXBP5) is a 1,118-amino-acid cytoplasmic protein that contains a C-terminal R-SNARE domain and an N-terminal WD40 repeat region. It binds syntaxin-1A and sequesters it from forming the SNARE complex, thereby acting as a negative regulator of vesicle fusion. In platelets, tomosyn controls the release of granular contents; loss of function leads to uncontrolled secretion and bleeding diathesis. The protein is also implicated in neuronal exocytosis and endocrine secretion.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| STXBP5L Knockout HEK293 Cell Line | EDJ-KQ6619 | Human | 9515 | Details Get a Quote |
| STXBP5 Knockout HEK293 Cell Line | EDJ-KQ9351 | Human | 134957 | Details Get a Quote |
| STXBP5 Knockout A-549 Cell Line | EDJ-KQ35991 | Human | 134957 | Details Get a Quote |
| STXBP5 Knockout HCT 116 Cell Line | EDJ-KQ35992 | Human | 134957 | Details Get a Quote |
| STXBP5 Knockout HeLa Cell Line | EDJ-KQ35993 | Human | 134957 | Details Get a Quote |
| STXBP5L Knockout HeLa Cell Line | EDJ-KQ29514 | Human | 9515 | Details Get a Quote |
| STXBP5L Knockout A-549 Cell Line | EDJ-KQ63666 | Human | 9515 | Details Get a Quote |
| STXBP5L Knockout HCT 116 Cell Line | EDJ-KQ72129 | Human | 9515 | Details Get a Quote |
