26S proteasome complex subunit DSS1 (DSS1)

26S proteasome complex subunit DSS1 (also known as SEM1) is an evolutionarily conserved, small, intrinsically disordered protein that functions as an integral component of the 19S regulatory particle "lid" of the 26S proteasome, the main ATP-dependent protease complex responsible for ubiquitin-mediated protein degradation in eukaryotes[1][2][4][5]. DSS1/SEM1 acts as a molecular tether, mediating the assembly and stability of the proteasome lid by specifically recruiting and stabilizing subunits such as Rpn3 and Rpn7 during proteasome maturation[2]. In addition to its role in proteasome assembly, DSS1/SEM1 participates in other multiprotein complexes, including the TREX-2 mRNA export complex and the BRCA2 complex involved in homologous recombination DNA repair[1][2][4]. Mutations or loss of DSS1/SEM1 can disrupt proteasome biogenesis, mitochondrial function, and lead to developmental defects such as split hand/foot malformation type 1, but it is not considered a direct therapeutic target or established biomarker in current clinical practice[1][2][4].

Other names

SEM1C7orf76SHFM1SHFDG1ECDPSMD15SHSF1SHFD1Split hand/foot deleted protein 1Deleted in split hand/split foot protein 1Split hand/foot malformation type 1 protein

Not drug-targeted; mechanism includes chaperone-like assembly function within the proteasome and facilitating the assembly or stability of multiprotein complexes[1][2][4].