AP4B1
Adaptor Related Protein Complex 4 Subunit Beta 1
Gene Information Card
| Symbol | AP4B1 |
|---|---|
| Full Name | Adaptor Related Protein Complex 4 Subunit Beta 1 |
| Gene Type | protein-coding |
| Chromosomal Location | 1p13.2 |
| NCBI Gene ID | 10717 ncbi.nlm.nih.gov/gene/10717 |
| Ensembl ID | ENSG00000134262 |
| UniProt ID | Q9Y6B7 |
| OMIM ID | 607245 |
| HGNC ID | 572 |
| Aliases | AP-4 beta, BETA4, SPG47 |
Description
AP4B1 encodes the beta subunit of the adaptor protein complex 4 (AP-4), which is involved in intracellular vesicle trafficking, specifically the sorting of transmembrane proteins from the trans-Golgi network to endosomes or lysosomes. Mutations in AP4B1 cause autosomal recessive hereditary spastic paraplegia type 47 (SPG47), a form of AP-4 deficiency syndrome characterized by early-onset spastic paraplegia, intellectual disability, and microcephaly.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hereditary Spastic Paraplegia 47 (SPG47) | Loss-of-function mutations impair AP-4 complex assembly, disrupting cargo sorting and neuronal development. | ClinVar, OMIM |
| AP-4 Deficiency Syndrome | Biallelic variants lead to defective autophagy and endosomal trafficking, causing neurological symptoms. | OMIM, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 8.2 | Medium |
| Testis | 6.5 | Medium |
| Lung | 4.1 | Low |
| Liver | 3.0 | Low |
| Kidney | 2.8 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SH-SY5Y | 9.1 | Neuronal model |
| HeLa | 7.3 | Cervical cancer |
| HEK293 | 6.8 | Embryonic kidney |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1132C>T (p.Arg378*) | Nonsense | Rare | Premature truncation, loss of function |
| c.1A>G (p.Met1?) | Start loss | Rare | No protein translation |
| c.1552C>T (p.Arg518Trp) | Missense | Rare | Impaired complex assembly |
Mutation functional classification
Loss of Function (LOF)
Most reported AP4B1 mutations are loss-of-function (nonsense, frameshift, splice-site), leading to AP-4 complex instability and impaired intracellular trafficking.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported; disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • intracellular protein transport | • vesicle-mediated transport |
| • protein localization to lysosome | • AP-4 adaptor complex |
| • clathrin adaptor activity |
Pathways
• AP-4 mediated vesicle transport
• Trans-Golgi network to endosome sorting
Protein Summary
AP4B1 is a 739-amino acid protein that forms the beta subunit of the heterotetrameric AP-4 complex. It mediates the recognition of tyrosine-based sorting signals on cargo proteins and facilitates vesicle budding from the trans-Golgi network. Defects in AP4B1 disrupt neuronal protein trafficking, leading to progressive spasticity and neurodevelopmental delay.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| AP4B1 Knockout HEK293 Cell Line | EDJ-KQ7137 | Human | 10717 | Details Get a Quote |
| AP4B1 Knockout A-549 Cell Line | EDJ-KQ32025 | Human | 10717 | Details Get a Quote |
| AP4B1 Knockout HCT 116 Cell Line | EDJ-KQ32026 | Human | 10717 | Details Get a Quote |
| AP4B1 Knockout HeLa Cell Line | EDJ-KQ32027 | Human | 10717 | Details Get a Quote |
