AP1S1
Adaptor Related Protein Complex 1 Subunit Sigma 1
Gene Information Card
| Symbol | AP1S1 |
|---|---|
| Full Name | Adaptor Related Protein Complex 1 Subunit Sigma 1 |
| Gene Type | protein-coding |
| Chromosomal Location | 7q22.1 |
| NCBI Gene ID | 1174 ncbi.nlm.nih.gov/gene/1174 |
| Ensembl ID | ENSG00000106367 |
| UniProt ID | P61966 |
| OMIM ID | 603531 |
| HGNC ID | 559 |
| Aliases | AP19, CLAPS1, sigma1A, sigma-adaptin 1A |
Description
AP1S1 encodes the sigma-1A subunit of the adaptor protein complex 1 (AP-1), which is essential for clathrin-coated vesicle assembly and intracellular trafficking between the trans-Golgi network and endosomes. Mutations in AP1S1 disrupt AP-1 function, leading to impaired protein sorting and are associated with MEDNIK syndrome (mental retardation, enteropathy, deafness, neuropathy, ichthyosis, keratoderma).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| MEDNIK syndrome | Loss-of-function mutations in AP1S1 impair AP-1 complex assembly, disrupting clathrin-mediated trafficking and causing multisystem developmental defects. | OMIM #609313; PMID: 18414213 |
| Intellectual disability | AP1S1 mutations contribute to synaptic vesicle trafficking deficits, affecting neuronal function. | PMID: 18414213 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.3 | Medium |
| Liver | 8.7 | Low |
| Kidney | 10.1 | Medium |
| Skin | 9.5 | Low |
| Small intestine | 11.2 | Medium |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 14.5 | High expression |
| HeLa | 13.2 | High expression |
| SH-SY5Y | 11.8 | Medium expression |
| HepG2 | 9.3 | Low expression |
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.346C>T (p.Arg116*) | nonsense | Rare | Premature stop, loss of function |
| c.160G>A (p.Gly54Arg) | missense | Rare | Disrupts sigma subunit folding, loss of function |
Mutation functional classification
Loss of Function (LOF)
Most AP1S1 mutations are loss-of-function, leading to AP-1 complex instability and impaired vesicle trafficking.
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)
| • clathrin adaptor complex | • intracellular protein transport |
| • vesicle-mediated transport | • Golgi to endosome transport |
| • protein binding |
Pathways
• Clathrin-mediated endocytosis
• AP-1 complex assembly
• Intracellular vesicle trafficking
Protein Summary
The AP1S1 protein (sigma-1A subunit) is a 19 kDa component of the AP-1 adaptor complex. It stabilizes the complex and mediates interactions with clathrin and cargo proteins. Loss of function disrupts sorting of transmembrane proteins, leading to cellular trafficking defects and multisystem disease.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| AP1S1 Knockout Hep-G2 Cell Line | EDJ-KZ544 | Human | 1174 | Details Get a Quote |
| AP1S1 Knockout HEK293 Cell Line | EDJ-KQ50196 | Human | 1174 | Details Get a Quote |
| AP1S1 Knockout HeLa Cell Line | EDJ-KQ52919 | Human | 1174 | Details Get a Quote |
| AP1S1 Knockout A-549 Cell Line | EDJ-KQ61386 | Human | 1174 | Details Get a Quote |
| AP1S1 Knockout HCT 116 Cell Line | EDJ-KQ69881 | Human | 1174 | Details Get a Quote |
