title: UBA domains of DNA damage-inducible proteins interact with ubiquitin.
abstract: Rad23 is a highly conserved protein involved in nucleotide excision repair (NER) that associates with the proteasome via its N-terminus. Its C-terminal ubiquitin-associated (UBA) domain is evolutionarily conserved from yeast to humans. However, the cellular function of UBA domains is not completely understood. Recently, RAD23 and DDI1, both DNA damage-inducible genes encoding proteins with UBA domains, were implicated genetically in Pds1-dependent mitotic control in yeast. The UBA domains of RAD23 and DDI1 are required for these interactions. Timely degradation of Pds1 via the ubiquitin/proteasome pathway allows anaphase onset and is crucial for chromosome maintenance. Here, we show that Rad23 and Ddi1 interact directly with ubiquitin and that this interaction is dependent on their UBA domains, providing a possible mechanism for UBA-dependent cell cycle control. Moreover, we show that a hydrophobic surface on the UBA domain, which from structural work had been predicted to be a protein-protein interaction interface, is indeed required for ubiquitin binding. By demonstrating that UBA domains interact with ubiquitin, we have provided the first indication of a cellular function for the UBA domain.
authors.affiliation: Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: B L
authors.initials: BL
authors.lastname: Bertolaet
authors.forename: D J
authors.initials: DJ
authors.lastname: Clarke
authors.forename: M
authors.initials: M
authors.lastname: Wolff
authors.forename: M H
authors.initials: MH
authors.lastname: Watson
authors.forename: M
authors.initials: M
authors.lastname: Henze
authors.forename: G
authors.initials: G
authors.lastname: Divita
authors.forename: S I
authors.initials: SI
authors.lastname: Reed
mesh_terms: D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D004249:DNA Damage / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D017354:Point Mutation / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D020798:Two-Hybrid System Techniques; D014452:Ubiquitins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C108125:DDI1 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C490846:RAD23 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins