title: Ubiquitin chains in the Dsk2 UBL domain mediate Dsk2 stability and protein degradation in yeast.
abstract: Ubiquitin-like (UBL)-ubiquitin-associated (UBA) proteins, including Dsk2 and Rad23, act as delivery factors that target polyubiquitinated substrates to the proteasome. We report here that the Dsk2 UBL domain is ubiquitinated in yeast cells and that Dsk2 ubiquitination of the UBL domain is involved in Dsk2 stability, depending on the Dsk2 UBA domain. Also, Dsk2 lacking ubiquitin chains impaired ubiquitin-dependent protein degradation and decreased the interaction of Dsk2 with polyubiquitinated proteins in cells. Moreover, Dsk2 ubiquitination affected ability to restore the temperature-sensitive growth defect of dsk2Δ. These results indicate that ubiquitination in the UBL domain of Dsk2 has in vivo functions in the ubiquitin-proteasome pathway in yeast.
authors.affiliation: Department of Molecular Biology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan. sekigu@molbiol.med.kyushu-u.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sekiguchi
authors.forename: Toru
authors.initials: T
authors.lastname: Sasaki
authors.forename: Minoru
authors.initials: M
authors.lastname: Funakoshi
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishii
authors.forename: Yoh-hei
authors.initials: YH
authors.lastname: Saitoh
authors.forename: Shu-ichi
authors.initials: S
authors.lastname: Kaneko
authors.forename: Hideki
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*; D054875:Ubiquitination; D014452:Ubiquitins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; C100415:DSK2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; D014452:Ubiquitins