title: The interactome of the atypical phosphatase Rtr1 in Saccharomyces cerevisiae.
abstract: The phosphatase Rtr1 has been implicated in dephosphorylation of the RNA Polymerase II (RNAPII) C-terminal domain (CTD) during transcription elongation and in regulation of nuclear import of RNAPII. Although it has been shown that Rtr1 interacts with RNAPII in yeast and humans, the specific mechanisms that underlie Rtr1 recruitment to RNAPII have not been elucidated. To address this, we have performed an in-depth proteomic analysis of Rtr1 interacting proteins in yeast. Our studies revealed that hyperphosphorylated RNAPII is the primary interacting partner for Rtr1. To extend these findings, we performed quantitative proteomic analyses of Rtr1 interactions in yeast strains deleted for CTK1, the gene encoding the catalytic subunit of the CTD kinase I (CTDK-I) complex. Interestingly, we found that the interaction between Rtr1 and RNAPII is decreased in ctk1Δ strains. We hypothesize that serine-2 CTD phosphorylation is required for Rtr1 recruitment to RNAPII during transcription elongation.
authors.affiliation: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA. almosley@iu.edu.
authors.forename: Whitney R
authors.initials: WR
authors.lastname: Smith-Kinnaman
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Berna
authors.forename: Gerald O
authors.initials: GO
authors.lastname: Hunter
authors.forename: Jason D
authors.initials: JD
authors.lastname: True
authors.forename: Peter
authors.initials: P
authors.lastname: Hsu
authors.forename: Gabriela I
authors.initials: GI
authors.lastname: Cabello
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Fox
authors.forename: Gabriele
authors.initials: G
authors.lastname: Varani
authors.forename: Amber L
authors.initials: AL
authors.lastname: Mosley
mesh_terms: D020134:Catalytic Domain; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics*; D040901:Proteomics; D012319:RNA Polymerase II / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: C118305:CTDK-I protein complex, S cerevisiae; C530135:Rtr1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012694:Serine; D011494:Protein Kinases; D012319:RNA Polymerase II