STXBP2
Syntaxin Binding Protein 2
Gene Information Card
| Symbol | STXBP2 |
|---|---|
| Full Name | Syntaxin Binding Protein 2 |
| Gene Type | protein-coding |
| Chromosomal Location | 19p13.2 |
| NCBI Gene ID | 6813 ncbi.nlm.nih.gov/gene/6813 |
| Ensembl ID | ENSG00000176974 |
| UniProt ID | Q15833 |
| OMIM ID | 601717 |
| HGNC ID | 11445 |
| Aliases | Munc18-2, UNC18B, MUNC18-2, p67 |
Description
STXBP2 encodes Munc18-2, a member of the Sec1/Munc18 family involved in vesicle trafficking and exocytosis. It binds syntaxins (STX3, STX4) to regulate SNARE complex assembly, critical for granule exocytosis in cytotoxic T lymphocytes and natural killer cells. Mutations cause familial hemophagocytic lymphohistiocytosis type 5 (FHL5), a severe primary immunodeficiency.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Familial hemophagocytic lymphohistiocytosis type 5 (FHL5) | Loss-of-function mutations impair cytotoxic granule exocytosis, leading to uncontrolled immune activation and hyperinflammation. | ClinVar, OMIM |
| Hemophagocytic lymphohistiocytosis (HLH) secondary | Defective degranulation in NK and T cells contributes to HLH pathogenesis. | NCBI Gene, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Whole blood | 14.5 | Medium |
| Spleen | 12.3 | Medium |
| Lung | 8.7 | Low |
| Small intestine | 7.9 | Low |
| Bone marrow | 6.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| NK-92 | 18.2 | High expression in NK cell line |
| Jurkat | 15.1 | High expression in T cell line |
| K-562 | 12.8 | Moderate expression |
| HeLa | 5.3 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.124C>T (p.Arg42Cys) | Missense | Rare | Reduced binding to syntaxin-11, impaired degranulation |
| c.259G>A (p.Gly87Arg) | Missense | Rare | Loss of function, associated with FHL5 |
| c.1621G>A (p.Glu541Lys) | Missense | Rare | Dominant-negative effect, disrupts SNARE complex |
| c.1A>G (p.Met1?) | Start loss | Rare | Complete loss of protein expression |
Mutation functional classification
Loss of Function (LOF)
Most FHL5-associated mutations are loss-of-function, leading to defective cytotoxic granule exocytosis.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Some missense mutations (e.g., p.Glu541Lys) exhibit dominant-negative effects by interfering with wild-type Munc18-2 function.
View complete mutation data：
Gene Ontology (GO)
| • exocytosis (GO:0006887) | • synaptic vesicle exocytosis (GO:0016079) |
| • vesicle docking (GO:0048278) | • SNARE binding (GO:0000149) |
| • protein binding (GO:0005515) | • SNARE complex assembly (GO:0031201) |
Pathways
• Vesicle-mediated transport (R-HSA-5653656)
• Membrane trafficking (R-HSA-199991)
• SNARE interactions in vesicular transport (KEGG hsa04130)
Protein Summary
Munc18-2 (STXBP2) is a 67 kDa cytosolic protein that regulates SNARE-mediated membrane fusion. It binds syntaxin-3 and syntaxin-4, controlling granule exocytosis in hematopoietic cells. Defects in this protein impair immune cell degranulation, leading to familial hemophagocytic lymphohistiocytosis type 5.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| STXBP2 Knockout HEK293 Cell Line | EDJ-KQ5868 | Human | 6813 | Details Get a Quote |
| STXBP2 Knockout A-549 Cell Line | EDJ-KQ29353 | Human | 6813 | Details Get a Quote |
| STXBP2 Knockout HCT 116 Cell Line | EDJ-KQ29354 | Human | 6813 | Details Get a Quote |
| STXBP2 Knockout HeLa Cell Line | EDJ-KQ29355 | Human | 6813 | Details Get a Quote |
