Structural highlights
Function
[PAN_PYRFU] ATPase which is responsible for recognizing, binding, unfolding and translocation of substrate proteins into the archaeal 20S proteasome core particle. Is essential for opening the gate of the 20S proteasome via an interaction with its C-terminus, thereby allowing substrate entry and access to the site of proteolysis. Thus, the C-termini of the proteasomal ATPase function like a 'key in a lock' to induce gate opening and therefore regulate proteolysis. Unfolding activity requires energy from ATP hydrolysis, whereas ATP binding alone promotes ATPase-20S proteasome association which triggers gate opening, and supports translocation of unfolded substrates (By similarity). [PSMD9_YEAST] Acts as a chaperone during the assembly of the 26S proteasome, specifically of the base subcomplex of the 19S regulatory complex (RC). During the base subcomplex assembly is part of a NAS2:RPT4:RPT5 module; NAS2 is released during the further base assembly process.
Publication Abstract from PubMed
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.
Structural Basis for Proteasome Formation Controlled by an Assembly Chaperone Nas2.,Satoh T, Saeki Y, Hiromoto T, Wang YH, Uekusa Y, Yagi H, Yoshihara H, Yagi-Utsumi M, Mizushima T, Tanaka K, Kato K Structure. 2014 Mar 25. pii: S0969-2126(14)00070-7. doi:, 10.1016/j.str.2014.02.014. PMID:24685148[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Satoh T, Saeki Y, Hiromoto T, Wang YH, Uekusa Y, Yagi H, Yoshihara H, Yagi-Utsumi M, Mizushima T, Tanaka K, Kato K. Structural Basis for Proteasome Formation Controlled by an Assembly Chaperone Nas2. Structure. 2014 Mar 25. pii: S0969-2126(14)00070-7. doi:, 10.1016/j.str.2014.02.014. PMID:24685148 doi:http://dx.doi.org/10.1016/j.str.2014.02.014
