title: N-Terminal Coiled-Coil Structure of ATPase Subunits of 26S Proteasome Is Crucial for Proteasome Function.
abstract: The proteasome is an essential proteolytic machine in eukaryotic cells, where it removes damaged proteins and regulates many cellular activities by degrading ubiquitinated proteins. Its heterohexameric AAA+ ATPase Rpt subunits play a central role in proteasome activity by the engagement of substrate unfolding and translocation for degradation; however, its detailed mechanism remains poorly understood. In contrast to AAA+ ATPase domains, their N-terminal regions of Rpt subunits substantially differ from each other. Here, to investigate the requirements and roles of the N-terminal regions of six Rpt subunits derived from Saccharomyces cerevisiae, we performed systematic mutational analysis using conditional knockdown yeast strains for each Rpt subunit and bacterial heterologous expression system of the base subcomplex. We showed that the formation of the coiled-coil structure was the most important for the N-terminal region of Rpt subunits. The primary role of coiled-coil structure would be the maintenance of the ring structure with the defined order. However, the coiled-coil region would be also be involved in substrate recognition and an interaction between lid and base subcomplexes.
authors.affiliation: Frontier Research Core for Life Sciences, University of Toyama, 3190 Gofuku, Toyma-shi, Toyama, 930-8555, Japan.
authors.forename: Tomonao
authors.initials: T
authors.lastname: Inobe
authors.affiliation: Frontier Research Core for Life Sciences, University of Toyama, 3190 Gofuku, Toyma-shi, Toyama, 930-8555, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Genmei
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004252:DNA Mutational Analysis; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae
chemical_list: D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; D000251:Adenosine Triphosphatases