In Saccharomyces cerevisiae, the Pho84 phosphate transporter acts as the main provider of phosphate to the cell using a proton symport mechanism, but also mediates rapid activation of the PKA (protein kinase A) pathway. These two features led to recognition of Pho84 as a transceptor. Although the physiological role of Pho84 has been studied in depth, the mechanisms underlying the transport and sensor functions are unclear. To obtain more insight into the structure–function relationships of Pho84, we have rationally designed and analysed site-directed mutants. Using a three-dimensional model of Pho84 created on the basis of the GlpT permease, complemented with multiple sequence alignments, we selected Arg168 and Lys492, and Asp178, Asp358 and Glu473 as residues potentially involved in phosphate or proton binding respectively, during transport. We found that Asp358 (helix 7) and Lys492 (helix 11) are critical for the transport function, and might be part of the putative substrate-binding pocket of Pho84. Moreover, we show that alleles mutated in the putative proton-binding site Asp358 are still capable of strongly activating PKA pathway targets, despite their severely reduced transport activity. This indicates that signalling does not require transport and suggests that mutagenesis of amino acid residues involved in binding of the co-transported ion may constitute a promising general approach to separate the transport and signalling functions in transceptors.
Skip Nav Destination
Article navigation
August 2012
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkEditorial Board
Research Article|
July 13 2012
Mutational analysis of putative phosphate- and proton-binding sites in the Saccharomyces cerevisiae Pho84 phosphate:H+ transceptor and its effect on signalling to the PKA and PHO pathways
Dieter R. Samyn;
Dieter R. Samyn
*School of Natural Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden
Search for other works by this author on:
Lorena Ruiz-Pávon;
Lorena Ruiz-Pávon
*School of Natural Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden
Search for other works by this author on:
Michael R. Andersson;
Michael R. Andersson
1
*School of Natural Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden
Search for other works by this author on:
Yulia Popova;
Yulia Popova
1
†Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Katholieke Universiteit Leuven, Kastelpark Arenberg 31, BE-3001 Leuven-Heverlee, Belgium
‡Department of Molecular Microbiology, Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Kasteelpark Arenberg 31, BE-3001 Leuven-Heverlee, Belgium
Search for other works by this author on:
Johan M. Thevelein;
Johan M. Thevelein
†Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Katholieke Universiteit Leuven, Kastelpark Arenberg 31, BE-3001 Leuven-Heverlee, Belgium
‡Department of Molecular Microbiology, Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Kasteelpark Arenberg 31, BE-3001 Leuven-Heverlee, Belgium
Search for other works by this author on:
Bengt L. Persson
Bengt L. Persson
2
*School of Natural Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden
†Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Katholieke Universiteit Leuven, Kastelpark Arenberg 31, BE-3001 Leuven-Heverlee, Belgium
‡Department of Molecular Microbiology, Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Kasteelpark Arenberg 31, BE-3001 Leuven-Heverlee, Belgium
2To whom correspondence should be addressed (email bengt.persson@lnu.se).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
November 29 2011
Revision Received:
May 14 2012
Accepted:
May 15 2012
Accepted Manuscript online:
May 15 2012
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© The Authors Journal compilation © 2012 Biochemical Society
2012
Biochem J (2012) 445 (3): 413–422.
Article history
Received:
November 29 2011
Revision Received:
May 14 2012
Accepted:
May 15 2012
Accepted Manuscript online:
May 15 2012
Citation
Dieter R. Samyn, Lorena Ruiz-Pávon, Michael R. Andersson, Yulia Popova, Johan M. Thevelein, Bengt L. Persson; Mutational analysis of putative phosphate- and proton-binding sites in the Saccharomyces cerevisiae Pho84 phosphate:H+ transceptor and its effect on signalling to the PKA and PHO pathways. Biochem J 1 August 2012; 445 (3): 413–422. doi: https://doi.org/10.1042/BJ20112086
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.