title: Nuclear translocation of Gln3 in response to nutrient signals requires Golgi-to-endosome trafficking in Saccharomyces cerevisiae.
abstract: The yeast Saccharomyces cerevisiae has developed specialized mechanisms that enable growth on suboptimal nitrogen sources. Exposure of yeast cells to poor nitrogen sources or treatment with the Tor kinase inhibitor rapamycin elicits activation of Gln3 and transcription of nitrogen catabolite-repressed (NCR) genes whose products function in scavenging and metabolizing nitrogen. Here, we show that mutations in class C and D Vps components, which mediate Golgi-to-endosome vesicle transport, impair nuclear translocation of Gln3, NCR gene activation, and growth in poor nitrogen sources. In nutrient-replete conditions, a significant fraction of Gln3 is peripherally associated with light membranes and partially colocalizes with Vps10-containing foci. These results reveal a role for Golgi-to-endosome vesicular trafficking in TORC1-controlled nuclear translocation of Gln3 and support a model in which Tor-mediated signaling in response to nutrient cues occurs in these compartments. These findings have important implications for nutrient sensing and growth control via mTor pathways in metazoans.
authors.affiliation: Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Rekha
authors.initials: R
authors.lastname: Puria
authors.forename: Sara A
authors.initials: SA
authors.lastname: Zurita-Martinez
authors.forename: Maria E
authors.initials: ME
authors.lastname: Cardenas
mesh_terms: D021581:Active Transport, Cell Nucleus; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D006056:Golgi Apparatus / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D009584:Nitrogen; D012097:Repressor Proteins / Q000378:metabolism / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology*; D013347:Subcellular Fractions / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation; D033921:Vesicular Transport Proteins / Q000378:metabolism
chemical_list: C071664:GLN3 protein, S cerevisiae; C087335:PEP1 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D033921:Vesicular Transport Proteins; D009584:Nitrogen