26S proteasome non-ATPase regulatory subunit 2

PSMD2 (26S proteasome non-ATPase regulatory subunit 2) is a core component of the 26S proteasome complex and plays a central role in ATP-dependent degradation of ubiquitinated proteins (UniProt: Q13200). This multiprotein machinery maintains cellular protein homeostasis by removing misfolded, damaged, or functionally obsolete proteins, thereby supporting critical processes including cell cycle progression, apoptosis, and DNA damage repair. PSMD2 also interacts with the intracellular domain of TNF receptor type 1.

Proteasomal dysfunction is implicated in neurodegeneration, as impaired protein quality control contributes to accumulation of pathological protein aggregates. PSMD2 is expressed throughout the brain and represents a key component of the cellular degradation machinery essential for neuronal health.

PSMD2 is significantly downregulated in Alzheimer's disease brain tissue relative to age-matched controls (Chaparral AD proteomics; mean log2 fold-change: −0.34). This reduced expression across the measured subcellular fraction suggests compromised proteasomal capacity in AD, potentially contributing to the pathological protein accumulation characteristic of the disease. The direction tag indicates consistent downregulation in the post-mortem AD brain proteomics dataset.