Structural basis for proteasome formation controlled by an assembly chaperone Nas2

Tadashi Satoh, Yasushi Saeki, Takeshi Hiromoto, Ying Hui Wang, Yoshinori Uekusa, Hirokazu Yagi, Hidehito Yoshihara, Maho Yagi-Utsumi, Tsunehiro Mizushima, Keiji Tanaka, Koichi Kato

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


Proteasome formation does not occur due to spontaneous self-organization but results from a highly ordered process assisted by several assembly chaperones. The assembly of the proteasome ATPase subunits is assisted by four client-specific chaperones, of which three have been structurally resolved. Here, we provide the structural basis for the working mechanisms of the last, hereto structurally uncharacterized assembly chaperone, Nas2. We revealed that Nas2 binds to the Rpt5 subunit in a bivalent mode: the N-terminal helical domain of Nas2 masks the Rpt1-interacting surface of Rpt5, whereas its C-terminal PDZ domain caps the C-terminal proteasome-activating motif. Thus, Nas2 operates as a proteasome activation blocker, offering a checkpoint during the formation of the 19S ATPase prior to its docking onto the proteolytic 20S core particle.

Original languageEnglish
Pages (from-to)731-743
Number of pages13
Issue number5
Publication statusPublished - 2014 May 6
Externally publishedYes

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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