title: Architecture of the Saccharomyces cerevisiae SAGA transcription coactivator complex.
abstract: The conserved transcription coactivator SAGA is comprised of several modules that are involved in activator binding, TBP binding, histone acetylation (HAT) and deubiquitination (DUB). Crosslinking and mass spectrometry, together with genetic and biochemical analyses, were used to determine the molecular architecture of the SAGA-TBP complex. We find that the SAGA Taf and Taf-like subunits form a TFIID-like core complex at the center of SAGA that makes extensive interactions with all other SAGA modules. SAGA-TBP binding involves a network of interactions between subunits Spt3, Spt8, Spt20, and Spt7. The HAT and DUB modules are in close proximity, and the DUB module modestly stimulates HAT function. The large activator-binding subunit Tra1 primarily connects to the TFIID-like core via its FAT domain. These combined results were used to derive a model for the arrangement of the SAGA subunits and its interactions with TBP. Our results provide new insight into SAGA function in gene regulation, its structural similarity with TFIID, and functional interactions between the SAGA modules.
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA Biological Physics, Structure and Design Program, University of Washington, Seattle, WA, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Han
authors.affiliation: Institute for Systems Biology, Seattle, WA, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Luo
authors.affiliation: Institute for Systems Biology, Seattle, WA, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Ranish
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA shahn@fhcrc.org.
authors.forename: Steven
authors.initials: S
authors.lastname: Hahn
mesh_terms: D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D035362:Transcription Factor TFIID / Q000235:genetics / Q000378:metabolism*
chemical_list: D046912:Multiprotein Complexes; C507785:SAGA complex, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D035362:Transcription Factor TFIID
keywords: coactivator; gene regulation; proteomics; transcription