Document Detail

Proline transport and stress tolerance of ammonia-insensitive mutants of the PUT4-encoded proline-specific permease in yeast.
MedLine Citation:
PMID:  20118607     Owner:  NLM     Status:  MEDLINE    
The imino amino acid, proline, has roles in both cellular nutrition and response to stress. Proline uptake in Saccharomyces cerevisiae is largely mediated by a high affinity, specific permease, Put4p, and a low affinity general amino acid permease, Gap1p. Both are subject to nitrogen catabolite repression (NCR) and nitrogen catabolite inactivation (NCI). In order for proline to be fully exploited, its transport must be derepressed, as occurs upon depletion of preferred nitrogen sources, and molecular oxygen must be present to allow the first step of catabolism via proline oxidase. This study focuses on the isolation of variants of Put4p, which are insensitive to repression by a preferred nitrogen source (ammonia) and their subsequent effect on proline transport and stress tolerance. Specific amino acid residues in the carboxy-terminal region of Put4p were targeted by site-directed mutagenesis. Substitution at Serine(605), a potential phosphorylation target, led to the amelioration of ammonia-induced down-regulation of Put4p. When combined with a promoter mutation (-160), the S(605)A mutation resulted in increased proline uptake and accumulation. This increase in proline accumulation was associated with increased cell viability in conditions of high temperature and osmotic stress raising possible benefits in industrial fermentation applications.
Kate Poole; Michelle E Walker; Tristan Warren; Jennie Gardner; Colin McBryde; Miguel de Barros Lopes; Vladimir Jiranek
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of general and applied microbiology     Volume:  55     ISSN:  0022-1260     ISO Abbreviation:  J. Gen. Appl. Microbiol.     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2010-02-01     Completed Date:  2010-03-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0165543     Medline TA:  J Gen Appl Microbiol     Country:  Japan    
Other Details:
Languages:  eng     Pagination:  427-39     Citation Subset:  IM    
School of Agriculture, Food and Wine, The University of Adelaide, Glen Osmond, Australia.
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MeSH Terms
Amino Acid Transport Systems, Neutral / genetics*,  metabolism
Ammonia / metabolism,  pharmacology*
Gene Expression Regulation, Fungal
Heat-Shock Response*
Industrial Microbiology / methods
Mutagenesis, Site-Directed
Osmotic Pressure*
Proline / metabolism
Saccharomyces cerevisiae* / drug effects,  genetics,  metabolism,  physiology
Reg. No./Substance:
0/Amino Acid Transport Systems, Neutral; 147-85-3/Proline; 7664-41-7/Ammonia; 7727-37-9/Nitrogen; 9040-98-6/proline transporter

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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