Document Detail


Saccharomyces cerevisiae glucose signalling regulator Mth1p regulates the organellar Na+/H+ exchanger Nhx1p.
MedLine Citation:
PMID:  20858221     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Organelle-localized NHEs (Na+/H+ exchangers) are found in cells from yeast to humans and contribute to organellar pH regulation by exporting H+ from the lumen to the cytosol coupled to an H+ gradient established by vacuolar H+-ATPase. The mechanisms underlying the regulation of organellar NHEs are largely unknown. In the present study, a yeast two-hybrid assay identified Mth1p as a new binding protein for Nhx1p, an organellar NHE in Saccharomyces cerevisiae. It was shown by an in vitro pull-down assay that Mth1p bound to the hydrophilic C-terminal half of Nhx1p, especially to the central portion of this region. Mth1p is known to bind to the cytoplasmic domain of the glucose sensor Snf3p/Rgt2p and also functions as a negative transcriptional regulator. Mth1p was expressed in cells grown in a medium containing galactose, but was lost (possibly degraded) when cells were grown in medium containing glucose as the sole carbon source. Deletion of the MTH1 gene increased cell growth compared with the wild-type when cells were grown in a medium containing galactose and with hygromycin or at an acidic pH. This resistance to hygromycin or acidic conditions was not observed for cells grown with glucose as the sole carbon source. Gene knockout of NHX1 increased the sensitivity to hygromycin and acidic pH. The increased resistance to hygromycin was reproduced by truncation of the Mth1p-binding region in Nhx1p. These results implicate Mth1p as a novel regulator of Nhx1p that responds to specific extracellular carbon sources.
Authors:
Keiji Mitsui; Masafumi Matsushita; Hiroshi Kanazawa
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Biochemical journal     Volume:  432     ISSN:  1470-8728     ISO Abbreviation:  Biochem. J.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-11-15     Completed Date:  2010-12-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  England    
Other Details:
Languages:  eng     Pagination:  343-52     Citation Subset:  IM    
Affiliation:
Department of Biological Sciences, Graduate School of Science, Osaka University 1-1 Machikaneyama-cho, Toyonaka City, Osaka 560-0043, Japan.
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MeSH Terms
Descriptor/Qualifier:
Adaptor Proteins, Signal Transducing / chemistry,  deficiency,  genetics,  metabolism*
Base Sequence
DNA Primers
Escherichia coli / genetics
Gene Expression Regulation, Fungal
Gene Knockout Techniques
Homeostasis
Humans
Immunoblotting
Organelles / metabolism*
Plasmids / genetics
Recombinant Fusion Proteins / metabolism
Recombinant Proteins / metabolism
Saccharomyces cerevisiae / genetics,  metabolism*
Saccharomyces cerevisiae Proteins / chemistry,  genetics,  metabolism*
Sodium-Hydrogen Antiporter / chemistry,  genetics,  metabolism*
Chemical
Reg. No./Substance:
0/Adaptor Proteins, Signal Transducing; 0/DNA Primers; 0/MTH1 protein, S cerevisiae; 0/Recombinant Fusion Proteins; 0/Recombinant Proteins; 0/Saccharomyces cerevisiae Proteins; 0/Sodium-Hydrogen Antiporter

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