Crystal structure of yeast rpn14, a chaperone of the 19 S regulatory particle of the proteasome.
The ubiquitin-proteasome pathway is a major proteolytic system in eukaryotic cells and regulates various cellular processes. The 26 S proteasome, the central enzyme of this pathway, consists of a proteolytic core particle and two 19 S regulatory particles (RPs) composed of ATPase (Rpt) and non-ATPase (Rpn) subunits. Growing evidence indicates that proteasome assembly is assisted by a variety of chaperones. In particular, it has been reported recently that Nas2, Nas6, Rpn14, and Hsm3 bind specific Rpt subunits, thereby contributing to the formation of 19 S RP. Rpn14 transiently binds to the C-terminal domain of the Rpt6 subunit (Rpt6-C) during maturation of the ATPase ring of 19 S RP. In this study, we determined the crystal structure of yeast Rpn14 at 2.0 A resolution, which revealed that this chaperone consists of a unique N-terminal domain with unknown function and a C-terminal domain assuming a canonical seven-bladed beta-propeller fold. The Rpt6-binding site on Rpn14 was predicted based on structural comparison with the complex formed between Nas6 and Rpt3-C. The top face of Rpn14 exhibits a highly acidic surface area, whereas the putative interacting surface of Rpt6-C is basic. By inspection of structural data along with genetic and biochemical data, we determined the specific residues of Rpn14 and Rpt6 for complementary charge interactions that are required for 19 S RP assembly.
Kim
Sangwoo
S
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603.
Saeki
Yasushi
Y
Laboratory of Frontier Science, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506.
Fukunaga
Keisuke
K
Laboratory of Frontier Science, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506.
Suzuki
Atsuo
A
Department of Biotechnology, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603.
Takagi
Kenji
K
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603.
Yamane
Takashi
T
Department of Biotechnology, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603.
Tanaka
Keiji
K
Laboratory of Frontier Science, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506.
Mizushima
Tsunehiro
T
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603.
Kato
Koichi
K
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603; Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan. Electronic address: kkato@phar.nagoya-cu.ac.jp.
D015153:Blotting, Western; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004591:Electrophoresis, Polyacrylamide Gel; D008958:Models, Molecular; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D002352:Carrier Proteins; D029701:Saccharomyces cerevisiae Proteins; D046988:Proteasome Endopeptidase Complex; C542569:Rpn14 protein, S cerevisiae