Vacuolar protein sorting-associated protein VTA1 homolog

VTA1 (vacuolar protein sorting-associated protein VTA1 homolog) is a 307-amino acid cofactor protein that functions in the endosomal multivesicular body (MVB) pathway (UniProt: Q9NP79). It works alongside VPS4A/B to disassemble membrane-associated ESCRT-III complexes, facilitating the sorting and degradation of membrane proteins including EGFR and lysosomal enzymes. VTA1 also participates in HIV-1 budding.

The protein localizes to endosomal compartments where it regulates intraluminal vesicle formation and lysosomal delivery of cargo. No disease associations are documented in the UniProt record (UniProt: Q9NP79).

VTA1 is curated as downregulated in Alzheimer's disease (Chaparral AD proteomics), with a mean log2 fold-change of −1.114 in post-mortem AD brain tissue relative to age-matched controls. This finding derives from TMT-labeled quantitative proteomics across four subcellular fractions (P2, P3, S2, S3) from human post-mortem brain. The reduced VTA1 abundance in AD may reflect altered endosomal-lysosomal function, a pathway implicated in amyloid and tau processing.