Mutational and Combinatorial Control of Self-Assembling and Disassembling of Human Proteasome ? Subunits.

ABSTRACT: Eukaryotic proteasomes harbor heteroheptameric ?-rings, each composed of seven different but homologous subunits ?1-?7, which are correctly assembled via interactions with assembly chaperones. The human proteasome ?7 subunit is reportedly spontaneously assembled into a homotetradecameric double ring, which can be disassembled into single rings via interaction with monomeric ?6. We comprehensively characterized the oligomeric state of human proteasome ? subunits and demonstrated that only the ?7 subunit exhibits this unique, self-assembling property and that not only ?6 but also ?4 can disrupt the ?7 double ring. We also demonstrated that mutationally monomerized ?7 subunits can interact with the intrinsically monomeric ?4 and ?6 subunits, thereby forming heterotetradecameric complexes with a double-ring structure. The results of this study provide additional insights into the mechanisms underlying the assembly and disassembly of proteasomal subunits, thereby offering clues for the design and creation of circularly assembled hetero-oligomers based on homo-oligomeric structural frameworks.

SUBMITTER: Sekiguchi T 

PROVIDER: S-EPMC6539845 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature