title: Components of Golgi-to-vacuole trafficking are required for nitrogen- and TORC1-responsive regulation of the yeast GATA factors.
abstract: Nitrogen catabolite repression (NCR) is the regulatory pathway through which Saccharomyces cerevisiae responds to the available nitrogen status and selectively utilizes rich nitrogen sources in preference to poor ones. Expression of NCR-sensitive genes is mediated by two transcription activators, Gln3 and Gat1, in response to provision of a poorly used nitrogen source or following treatment with the TORC1 inhibitor, rapamycin. During nitrogen excess, the transcription activators are sequestered in the cytoplasm in a Ure2-dependent fashion. Here, we show that Vps components are required for Gln3 localization and function in response to rapamycin treatment when cells are grown in defined yeast nitrogen base but not in complex yeast peptone dextrose medium. On the other hand, Gat1 function was altered in vps mutants in all conditions tested. A significant fraction of Gat1, like Gln3, is associated with light intracellular membranes. Further, our results are consistent with the possibility that Ure2 might function downstream of the Vps components during the control of GATA factor-mediated gene expression. These observations demonstrate distinct media-dependent requirements of vesicular trafficking components for wild-type responses of GATA factor localization and function. As a result, the current model describing participation of Vps system components in events associated with translocation of Gln3 into the nucleus following rapamycin treatment or growth in nitrogen-poor medium requires modification.
authors.affiliation: Institut de Recherches Microbiologiques J.-M. Wiame, Laboratoire de Microbiologie, Université Libre de Bruxelles, 1070, Brussels, Belgium; Laboratoire de Biologie du Transport Membranaire, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, 6041, Gosselies, Belgium.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Fayyadkazan
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Tate
authors.forename: Fabienne
authors.initials: F
authors.lastname: Vierendeels
authors.forename: Terrance G
authors.initials: TG
authors.lastname: Cooper
authors.forename: Evelyne
authors.initials: E
authors.lastname: Dubois
authors.forename: Isabelle
authors.initials: I
authors.lastname: Georis
mesh_terms: D003470:Culture Media / Q000737:chemistry; D050980:GATA Transcription Factors / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D006056:Golgi Apparatus / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D003470:Culture Media; D050980:GATA Transcription Factors; D029701:Saccharomyces cerevisiae Proteins; C561842:TORC1 protein complex, S cerevisiae; D014157:Transcription Factors; D009584:Nitrogen
keywords: GATA factor; nitrogen availability; rapamycin; vesicular trafficking; yeast