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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
2001-11-19
pubmed:abstractText
Membrane trafficking of the general amino acid permease (Gap1) of Saccharomyces cerevisiae is under nitrogen regulation. In cells growing on proline or urea as the sole nitrogen source, newly synthesized Gap1 is delivered to the plasma membrane, where it accumulates. Upon addition of NH(4)(+), a preferential nitrogen source, Gap1 is endocytosed and targeted to the vacuole, where it is degraded. This down-regulation requires ubiquitination of the permease, and this ubiquitination is dependent on the essential Npi1/Rsp5 ubiquitin ligase. In this study, we investigated the role of the Npr1 kinase in the regulation of Gap1 trafficking. We show that Npr1 is required for stabilization of Gap1 at the plasma membrane: when an npr1(ts) mutant growing on proline is shifted to the restrictive temperature, Gap1 down-regulation is triggered, as it is when NH(4)(+) is added to wild-type cells. The fate of newly synthesized Gap1 en route to the plasma membrane is also under Npr1 control: in an npr1Delta mutant, neosynthesized Gap1 is sorted from the Golgi to the vacuole without passing via the plasma membrane. Similar direct sorting of neosynthesized Gap1 to the vacuole was observed in wild-type cells grown on NH(4)(+). Finally, Gap1 is phosphorylated in NPR1 cells, but this phosphorylation is not strictly dependent on Npr1. Our results show that Npr1 kinase plays a central role in the physiological control of Gap1 trafficking and that this control is exerted not only on Gap1 present at the plasma membrane but also on Gap1 late in the secretory pathway. Npr1 belongs to a subgroup of protein kinases, some of which are reported to exert a positive control on the activity of other permeases. We propose that these kinases also function as regulators of permease trafficking.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Amino Acid Transport Systems, http://linkedlifedata.com/resource/pubmed/chemical/DNA Primers, http://linkedlifedata.com/resource/pubmed/chemical/Fungal Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Green Fluorescent Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Luminescent Proteins, http://linkedlifedata.com/resource/pubmed/chemical/NPR1 protein, S cerevisiae, http://linkedlifedata.com/resource/pubmed/chemical/Protein Kinases, http://linkedlifedata.com/resource/pubmed/chemical/Protein-Serine-Threonine Kinases, http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Fusion Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Saccharomyces cerevisiae Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Ubiquitin
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
43939-48
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:11500493-Amino Acid Transport Systems, pubmed-meshheading:11500493-Base Sequence, pubmed-meshheading:11500493-DNA Primers, pubmed-meshheading:11500493-Endocytosis, pubmed-meshheading:11500493-Fungal Proteins, pubmed-meshheading:11500493-Golgi Apparatus, pubmed-meshheading:11500493-Green Fluorescent Proteins, pubmed-meshheading:11500493-Luminescent Proteins, pubmed-meshheading:11500493-Molecular Sequence Data, pubmed-meshheading:11500493-Phosphorylation, pubmed-meshheading:11500493-Protein Kinases, pubmed-meshheading:11500493-Protein-Serine-Threonine Kinases, pubmed-meshheading:11500493-Recombinant Fusion Proteins, pubmed-meshheading:11500493-Saccharomyces cerevisiae, pubmed-meshheading:11500493-Saccharomyces cerevisiae Proteins, pubmed-meshheading:11500493-Ubiquitin, pubmed-meshheading:11500493-Vacuoles
pubmed:year
2001
pubmed:articleTitle
The Npr1 kinase controls biosynthetic and endocytic sorting of the yeast Gap1 permease.
pubmed:affiliation
Laboratoire de Physiologie Cellulaire, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, 12 rue des Professeurs Jeneer et Brachet, 6041 Gosselies, Belgium.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't