Fub1p, a novel protein isolated by boundary screening, binds the proteasome complex

Akira Hatanaka; Bo Chen; Jing-Qian Sun; Yasunobu Mano; Minoru Funakoshi; Hideki Kobayashi; Yunfeng Ju; Tetsuya Mizutani; Kaori Shinmyozu; Jun-ichi Nakayama; Kaoru Miyamoto; Hiroyuki Uchida; Masaya Oki

doi:10.1266/ggs.86.305

Full papers

Fub1p, a novel protein isolated by boundary screening, binds the proteasome complex

Akira Hatanaka, Bo Chen, Jing-Qian Sun, Yasunobu Mano, Minoru Funakoshi, Hideki Kobayashi, Yunfeng Ju, Tetsuya Mizutani, Kaori Shinmyozu, Jun-ichi Nakayama, Kaoru Miyamoto, Hiroyuki Uchida, Masaya Oki

Author information

Akira Hatanaka
Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui
Bo Chen
Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui
Jing-Qian Sun
Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui
Yasunobu Mano
Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui
Minoru Funakoshi
Center for Faculty Development, Okayama University
Hideki Kobayashi
Center for Faculty Development, Okayama University
Yunfeng Ju
Department of Biochemistry, Faculty of Medical Science, University of Fukui
Tetsuya Mizutani
Department of Biochemistry, Faculty of Medical Science, University of Fukui
Research and Education Program for Life Science, University of Fukui
Kaori Shinmyozu
Proteomics support unit, Center for Developmental Biology, RIKEN
Jun-ichi Nakayama
Laboratory for Chromatin Dynamics, Center for Developmental Biology, RIKEN
Kaoru Miyamoto
Department of Biochemistry, Faculty of Medical Science, University of Fukui
Research and Education Program for Life Science, University of Fukui
Hiroyuki Uchida
Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui
Masaya Oki
Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui
Research and Education Program for Life Science, University of Fukui
PRESTO, Japan Science and Technology Agency (JST)

Keywords: boundary, euchromatin and heterochromatin, gene silencing, proteasome, Saccharomyces cerevisiae

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2011 Volume 86 Issue 5 Pages 305-314

DOI https://doi.org/10.1266/ggs.86.305

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Abstract

Silenced chromatin domains are restricted to specific regions. Eukaryotic chromosomes are organized into discrete domains delimited by domain boundaries. From approximately 6,000 genes in Saccharomyces cerevisiae, we previously isolated 55 boundary genes. In this study, we focus on the molecular function of one of boundary genes, YCR076C/FUB1 (function of boundary), whose function has not been clearly defined in vivo. Biochemical analysis of Fub1p revealed that it interacted with multiple subunits of the 20S proteasome core particle (20S CP). To further clarify the functional link between Fub1p and proteasome, several proteasome mutants were analyzed. Although only 20S CP subunits were isolated as Fub1p interactors, a genetic interaction was also observed for component of 19S regulatory particle (19S RP) suggesting involvement of Fub1p with the whole proteasome. We also analyzed the mechanism of boundary establishment by using proteasome composition factor-deficient strains. Deletion of pre9 and ump1, whose products have effects on the 20S CP, resulted in a decrease in boundary function. Domain analyses of Fub1p identified a minimum functional domain in the C terminus that was essential for boundary establishment and showed a limited sequence homology to the human PSMF1, which is known to inhibit proteasome activity. Finally, boundary assay showed that human PSMF1 also exhibited boundary establishment activity in yeast. Our results defined the functional correlation between Fub1p and PSMF1.

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