title: The Prp19 U-box crystal structure suggests a common dimeric architecture for a class of oligomeric E3 ubiquitin ligases.
abstract: Prp19 is an essential splicing factor and a member of the U-box family of E3 ubiquitin ligases. Prp19 forms a tetramer via a central coiled-coil domain. Here, we show the U-box domain of Prp19 exists as a dimer within the context of the Prp19 tetramer. A high-resolution structure of the homodimeric state of the Prp19 U-box was determined by X-ray crystallography. Mutation of the U-box dimer interface abrogates U-box dimer formation and is lethal in vivo. The structure of the U-box dimer enables construction of a complete model of Prp19 providing insights into how the tetrameric protein functions as an E3 ligase. Finally, comparison of the Prp19 U-box homodimer with the heterodimeric complex of BRCA1/BARD1 RING-finger domains uncovers a common architecture for a family of oligomeric U-box and RING-finger E3 ubiquitin ligases, which has mechanistic implications for E3 ligase-mediated polyubiquitination and E4 polyubiquitin ligases.
authors.affiliation: Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, USA.
authors.forename: Craig W
authors.initials: CW
authors.lastname: Vander Kooi
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Ohi
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Rosenberg
authors.forename: Michael L
authors.initials: ML
authors.lastname: Oldham
authors.forename: Marcia E
authors.initials: ME
authors.lastname: Newcomer
authors.forename: Kathleen L
authors.initials: KL
authors.lastname: Gould
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Chazin
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D045643:DNA Repair Enzymes; D019281:Dimerization; D006801:Humans; D008956:Models, Chemical; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D025821:Polyubiquitin / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D000072260:RNA Splicing Factors; D012342:RNA, Small Nuclear; D013379:Substrate Specificity; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry* / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D009687:Nuclear Proteins; D000072260:RNA Splicing Factors; D012342:RNA, Small Nuclear; D025821:Polyubiquitin; D044763:Ubiquitin-Conjugating Enzymes; D044767:Ubiquitin-Protein Ligases; D045643:DNA Repair Enzymes; C417041:PRPF19 protein, human