Proteasome subunit beta type-8 (PSMB8) (PSMB8)

Proteasome subunit beta type-8 (PSMB8), also known as LMP7 or the β5i subunit, is a catalytic component of the immunoproteasome, a specialized form of the 20S proteasome induced by interferon-gamma [1, 10]. It possesses chymotrypsin-like proteolytic activity and plays a critical role in processing endogenous antigens for presentation on MHC class I molecules, thereby modulating CD8+ T cell responses [1, 6]. Beyond its role in the immune system, PSMB8 is involved in protein homeostasis, cell cycle regulation, and adipocyte differentiation [3, 8]. Dysregulation or mutations in PSMB8 are linked to a spectrum of diseases, including proteasome-associated autoinflammatory syndromes (PRAAS) like CANDLE syndrome, as well as various cancers and neurodegenerative disorders such as Parkinson's disease [3, 5, 14, 21]. In oncology, PSMB8 is often overexpressed in hematological malignancies and certain solid tumors, where it supports tumor cell survival and immune evasion [4, 6, 11]. Therapeutic strategies focus on selective inhibition of PSMB8 to treat autoimmune conditions and hematological malignancies, aiming to reduce systemic toxicity associated with pan-proteasome inhibitors [4, 21]. Selective inhibitors like zetomipzomib are currently being evaluated in clinical trials for their ability to modulate inflammatory cytokine production without the broad toxicity of earlier proteasome-targeting drugs [4, 21]. Overall, PSMB8 represents a high-value target for precision medicine in immunology and oncology [2, 4].

Other names

LMP7 [1, 7, 10]RING10 [1, 7, 10]Beta5i [1, 7]PSMB5i [1, 7, 10]D6S216E [1, 7, 10]JMP [1, 10]NKJO [1, 10]ALDD [1, 10]PRAAS1 [1, 10]

Selective inhibition of the chymotrypsin-like activity of the immunoproteasome (specifically the β5i subunit) [4, 11, 21]