NAPA Gene (NSF Attachment Protein Alpha)
Key regulator of intracellular membrane fusion and vesicular transport
Gene Information Card
| Symbol | NAPA |
|---|---|
| Full Name | NSF Attachment Protein Alpha |
| Gene Type | Protein coding |
| Chromosomal Location | 19q13.32 |
| NCBI Gene ID | 8775 ncbi.nlm.nih.gov/gene/8775 |
| Ensembl ID | ENSG00000104884 |
| UniProt ID | P54920 |
| OMIM ID | 603215 |
| HGNC ID | 7641 |
| Aliases | SNAP-alpha, NAPA-ALPHA |
Description
The NAPA gene encodes alpha-soluble NSF attachment protein (SNAP-alpha), a component of the SNARE complex essential for intracellular membrane fusion. SNAP-alpha binds to syntaxin and synaptobrevin, facilitating the assembly of the SNARE complex and subsequent vesicle docking and fusion. It is ubiquitously expressed and plays a critical role in neurotransmitter release, hormone secretion, and general vesicular transport.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| NAPA-related neurodevelopmental disorder | Disruption of SNARE complex assembly due to NAPA loss-of-function variants impairs synaptic vesicle fusion, leading to intellectual disability and developmental delay. | ClinVar, OMIM |
| Epileptic encephalopathy | Biallelic NAPA mutations cause impaired neurotransmitter release, resulting in early-onset seizures and encephalopathy. | ClinVar, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | High |
| Pancreas | 8.3 | Medium |
| Liver | 6.1 | Medium |
| Heart | 5.4 | Medium |
| Kidney | 4.8 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SH-SY5Y | 15.2 | Neuronal cell line, high expression |
| HeLa | 9.8 | Cervical cancer cell line |
| HEK293 | 7.6 | Embryonic kidney cell line |
| HepG2 | 6.3 | Liver cancer cell line |
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, likely loss of function |
| c.208C>T (p.Arg70Trp) | Missense | Rare | Impaired SNARE binding, loss of function |
| c.346G>A (p.Gly116Arg) | Missense | Rare | Reduced protein stability, loss of function |
Mutation functional classification
Loss of Function (LOF)
Most NAPA disease-associated mutations are loss-of-function, leading to reduced SNAP-alpha activity and impaired vesicle fusion.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported.
View complete mutation data：
Gene Ontology (GO)
| • SNARE binding | • intracellular protein transport |
| • vesicle fusion | • synaptic vesicle exocytosis |
| • membrane docking |
Pathways
• SNARE interactions in vesicular transport
• Neurotransmitter release cycle
• Membrane trafficking
Protein Summary
SNAP-alpha (UniProt P54920) is a 295-amino acid protein that functions as a soluble NSF attachment protein. It binds to syntaxin and synaptobrevin to promote SNARE complex assembly, which is essential for vesicle fusion. The protein is ubiquitously expressed and localizes to the cytosol and membrane compartments. Mutations in NAPA cause neurodevelopmental disorders due to impaired synaptic transmission.
Related Services
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