Proteasome subunit alpha type-1

PSMA1 (Proteasome subunit alpha type-1) is a core component of the 20S proteasome complex, which mediates ATP-dependent degradation of ubiquitinated proteins when associated with 19S regulatory particles to form the 26S proteasome (UniProt: P25786). The protein plays an essential role in protein homeostasis by removing misfolded, damaged, or functionally obsolete proteins. It can also participate in ubiquitin-independent proteolysis when bound to alternative regulatory complexes such as PA200 or PA28.

PSMA1 is widely expressed across tissues as part of a fundamental cellular degradation machinery. No specific disease associations are documented in UniProt records.

PSMA1 shows potential relevance to Alzheimer's Disease based on proteomic analysis of post-mortem AD brain tissue. In a comparative study of human AD brain versus age-matched controls using TMT-labeled quantitative proteomics across four subcellular fractions, PSMA1 regulation was ambiguous—the mean log2 fold-change was −0.0539, suggesting minimal net change or inconsistent direction across the measured fractions (Chaparral AD proteomics). This modest, bidirectional signal warrants further investigation into whether proteasome function is specifically altered in AD pathology.