UBAP1

This gene is a member of the UBA domain family, whose members include proteins having connections to ubiquitin and the ubiquitination pathway. The ubiquitin associated domain is thought to be a non-covalent ubiquitin binding domain consisting of a compact three helix bundle. This particular protein originates from a gene locus in a refined region on chromosome 9 undergoing loss of heterozygosity in nasopharyngeal carcinoma (NPC). Taking into account its cytogenetic location, this UBA domain family member is being studies as a putative target for mutation in nasopharyngeal carcinomas. Multiple alternatively spliced transcript variants encoding different isoforms have been found for this gene.

Full Name

ubiquitin-associated protein 1

Function

Component of the ESCRT-I complex, a regulator of vesicular trafficking process (PubMed:21757351, PubMed:22405001, PubMed:31203368).
Binds to ubiquitinated cargo proteins and is required for the sorting of endocytic ubiquitinated cargos into multivesicular bodies (MVBs) (PubMed:21757351, PubMed:22405001).
Plays a role in the proteasomal degradation of ubiquitinated cell-surface proteins, such as EGFR and BST2 (PubMed:24284069, PubMed:22405001, PubMed:31203368).

Biological Process

Biological Process membrane fission Source:ComplexPortal1 Publication
Biological Process multivesicular body assembly Source:ComplexPortal1 Publication
Biological Process protein transport to vacuole involved in ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway Source:ComplexPortal1 Publication
Biological Process ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway Source:UniProtKB1 Publication

Cellular Location

Cytoplasm, cytosol
Endosome
Predominantly cytosolic (PubMed:21757351).
Recruited to endosomes as part of the ESCRT-I complex (PubMed:21757351).

Involvement in disease

Spastic paraplegia 80, autosomal dominant (SPG80):
A form of spastic paraplegia, a neurodegenerative disorder characterized by a slow, gradual, progressive weakness and spasticity of the lower limbs. Rate of progression and the severity of symptoms are quite variable. Initial symptoms may include difficulty with balance, weakness and stiffness in the legs, muscle spasms, and dragging the toes when walking. In some forms of the disorder, bladder symptoms (such as incontinence) may appear, or the weakness and stiffness may spread to other parts of the body.