<scp>SQSTM1</scp> /p62 Orchestrates Skin Aging via <scp>USP7</scp> Degradation

Skin aging is a complex process driven by intrinsic genetic factors and extrinsic environmental influences. In this study, sequestosome1 (SQSTM1/p62) was identified as a key regulator of senescence, the senescence-associated secretory phenotype (SASP), and skin aging. Notably, p62 expression is reduced in senescent cells and aging skin of both humans and mice. The depletion of p62 in the epidermis was found to be positively associated with accelerated aging and the initiation of SASP. Mechanistically, p62 inhibits the accumulation of ubiquitin-specific protease 7 (USP7) during senescence induction by orchestrating its degradation through specific binding interactions. In particular, the Tyr-67 residue within the PB1 domain or Gln-418 within the UBA domain of p62 forms a hydrogen bond with Ala-993 in the Ubl5 domain of USP7. Mutations in either Tyr-67 or Gln-418 of p62, or Ala-993 of USP7, resulted in the induction of cellular senescence, highlighting the critical role of these molecular interactions in the regulation of aging processes.