Journal article
Regulation of Yeast Nutrient Permease Endocytosis by ATP-binding Cassette Transporters and a Seven-transmembrane Protein, RSB1
The Journal of biological chemistry, Vol.285(46), pp.35792-35802
11/01/2010
DOI: 10.1074/jbc.M110.162883
PMCID: PMC2975203
PMID: 20826817
Abstract
Ceramide is produced by the condensation of a long chain base with a very long chain fatty acid. In Saccharomyces cerevisiae, one of the two major long chain bases is called phytosphingosine (PHS). PHS has been shown to cause toxicity in tryptophan auxotrophic strains of yeast because this bioactive ceramide precursor causes diversion of the high affinity tryptophan permease Tat2 to the vacuole rather than the plasma membrane. Loss of the integral membrane protein Rsb1 increased PHS sensitivity, which was suggested to be due to this protein acting as an ATP-dependent long chain base efflux protein. More recent experiments demonstrated that loss of the genes encoding the ATP-binding cassette transporter proteins Pdr5 and Yor1 elevated PHS tolerance. This increased resistance was suggested to be due to increased expression of RSB1. Here, we provide an alternative view of PHS resistance influenced by Rsb1 and Pdr5/Yor1. Rsb1 has a seven-transmembrane domain topology more consistent with that of a regulatory protein like a G-protein-coupled receptor rather than a transporter. Importantly, an rsb1[delta] cell does not exhibit higher internal levels of PHS compared with isogenic wild-type cells. However, tryptophan transport is increased in pdr5[delta] yor1 strains and reduced in rsb1[delta] cells. Localization and vacuolar degradation of Tat2 are affected in these genetic backgrounds. Finally, internalization of FM4-64 dye suggests that loss of Pdr5 and Yor1 slows normal endocytic rates. Together, these data argue that Rsb1, Pdr5, and Yor1 regulate the endocytosis of Tat2 and likely other membrane transporter proteins.
Details
- Title: Subtitle
- Regulation of Yeast Nutrient Permease Endocytosis by ATP-binding Cassette Transporters and a Seven-transmembrane Protein, RSB1
- Creators
- Soraya Johnson - University of IowaPamela Hanson - Roy J. and Lucille A. Carver College of MedicineRaman Manoharlal - Roy J. and Lucille A. Carver College of MedicineSarah Brice - Medical University of South CarolinaLAshley CowartWScott Moye-Rowley
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.285(46), pp.35792-35802
- DOI
- 10.1074/jbc.M110.162883
- PMID
- 20826817
- PMCID
- PMC2975203
- NLM abbreviation
- J Biol Chem
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Language
- English
- Date published
- 11/01/2010
- Academic Unit
- Molecular Physiology and Biophysics; Internal Medicine
- Record Identifier
- 9984297614602771
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