title: The TFIIH subunit Tfb3 regulates cullin neddylation.
abstract: Cullin proteins are scaffolds for the assembly of multisubunit ubiquitin ligases, which ubiquitylate a large number of proteins involved in widely varying cellular functions. Multiple mechanisms cooperate to regulate cullin activity, including neddylation of their C-terminal domain. Interestingly, we found that the yeast Cul4-type cullin Rtt101 is not only neddylated but also ubiquitylated, and both modifications promote Rtt101 function in vivo. Surprisingly, proper modification of Rtt101 neither correlated with catalytic activity of the RING domain of Hrt1 nor required the Nedd8 ligase Dcn1. Instead, ubiquitylation of Rtt101 was dependent on the ubiquitin-conjugating enzyme Ubc4, while efficient neddylation involves the RING domain protein Tfb3, a subunit of the transcription factor TFIIH. Tfb3 also controls Cul3 neddylation and activity in vivo, and physically interacts with Ubc4 and the Nedd8-conjugating enzyme Ubc12 and the Hrt1/Rtt101 complex. Together, these results suggest that the conserved RING domain protein Tfb3 controls activation of a subset of cullins.
authors.affiliation: Institute of Biochemistry, ETH Zurich, Zurich, Switzerland. gwenael.rabut@univ-rennes1.fr
authors.forename: Gwenaël
authors.initials: G
authors.lastname: Rabut
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Le Dez
authors.forename: Rati
authors.initials: R
authors.lastname: Verma
authors.forename: Taras
authors.initials: T
authors.lastname: Makhnevych
authors.forename: Axel
authors.initials: A
authors.lastname: Knebel
authors.forename: Thimo
authors.initials: T
authors.lastname: Kurz
authors.forename: Charles
authors.initials: C
authors.lastname: Boone
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Deshaies
authors.forename: Matthias
authors.initials: M
authors.lastname: Peter
mesh_terms: D044842:Cullin Proteins / Q000378:metabolism*; D009154:Mutation; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D051758:Transcription Factor TFIIH / Q000502:physiology*; D019473:Transcription Factors, TFII / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics; D054875:Ubiquitination; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: C100988:Cdc53 protein, S cerevisiae; D044842:Cullin Proteins; C502135:Dcn1 protein, S cerevisiae; C476451:RTT101 protein, S cerevisiae; C111706:RUB1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C108124:TFB3 protein, S cerevisiae; D019473:Transcription Factors, TFII; D014452:Ubiquitins; D051758:Transcription Factor TFIIH; C485632:HRT1 protein, S cerevisiae; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases