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The intrinsic GTPase activity of the Gtr1 protein from Saccharomyces cerevisiae

Sengottaiyan, Palanivelu; Spetea, Cornelia; Lagerstedt, Jens LU ; Samyn, Dieter; Andersson, Michael; Ruiz-Pavon, Lorena and Persson, Bengt L. (2012) In BMC Biochemistry 13.
Abstract
Background: The Gtr1 protein of Saccharomyces cerevisiae is a member of the RagA subfamily of the Ras-like small GTPase superfamily. Gtr1 has been implicated in various cellular processes. Particularly, the Switch regions in the GTPase domain of Gtr1 are essential for TORC1 activation and amino acid signaling [R. Gong, L. Li, Y. Liu, P. Wang, H. Yang, L. Wang, J. Cheng, K. L. Guan, Y. Xu, Genes Dev. 25 (2011) 1668-1673]. Therefore, knowledge about the biochemical activity of Gtr1 is required to understand its mode of action and regulation. Results: By employing tryptophan fluorescence analysis and radioactive GTPase assays, we demonstrate that Gtr1 can adopt two distinct GDP- and GTP-bound conformations, and that it hydrolyses GTP much... (More)
Background: The Gtr1 protein of Saccharomyces cerevisiae is a member of the RagA subfamily of the Ras-like small GTPase superfamily. Gtr1 has been implicated in various cellular processes. Particularly, the Switch regions in the GTPase domain of Gtr1 are essential for TORC1 activation and amino acid signaling [R. Gong, L. Li, Y. Liu, P. Wang, H. Yang, L. Wang, J. Cheng, K. L. Guan, Y. Xu, Genes Dev. 25 (2011) 1668-1673]. Therefore, knowledge about the biochemical activity of Gtr1 is required to understand its mode of action and regulation. Results: By employing tryptophan fluorescence analysis and radioactive GTPase assays, we demonstrate that Gtr1 can adopt two distinct GDP- and GTP-bound conformations, and that it hydrolyses GTP much slower than Ras proteins. Using cysteine mutagenesis of Arginine-37 and Valine-67, residues at the Switch I and II regions, respectively, we show altered GTPase activity and associated conformational changes as compared to the wild type protein and the cysteine-less mutant. Conclusions: The extremely low intrinsic GTPase activity of Gtr1 implies requirement for interaction with activating proteins to support its physiological function. These findings as well as the altered properties obtained by mutagenesis in the Switch regions provide insights into the function of Gtr1 and its homologues in yeast and mammals. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Gtr1, GTPase, Intrinsic tryptophan fluorescence, Rag GTPase, Cysteine, mutagenesis, Switch region
in
BMC Biochemistry
volume
13
publisher
BioMed Central
external identifiers
  • wos:000310055500001
  • scopus:84862569403
ISSN
1471-2091
DOI
10.1186/1471-2091-13-11
language
English
LU publication?
yes
id
abd62169-a317-42d0-a29f-c50b9d341347 (old id 3287949)
date added to LUP
2013-01-07 09:44:41
date last changed
2017-07-23 04:09:41
@article{abd62169-a317-42d0-a29f-c50b9d341347,
  abstract     = {Background: The Gtr1 protein of Saccharomyces cerevisiae is a member of the RagA subfamily of the Ras-like small GTPase superfamily. Gtr1 has been implicated in various cellular processes. Particularly, the Switch regions in the GTPase domain of Gtr1 are essential for TORC1 activation and amino acid signaling [R. Gong, L. Li, Y. Liu, P. Wang, H. Yang, L. Wang, J. Cheng, K. L. Guan, Y. Xu, Genes Dev. 25 (2011) 1668-1673]. Therefore, knowledge about the biochemical activity of Gtr1 is required to understand its mode of action and regulation. Results: By employing tryptophan fluorescence analysis and radioactive GTPase assays, we demonstrate that Gtr1 can adopt two distinct GDP- and GTP-bound conformations, and that it hydrolyses GTP much slower than Ras proteins. Using cysteine mutagenesis of Arginine-37 and Valine-67, residues at the Switch I and II regions, respectively, we show altered GTPase activity and associated conformational changes as compared to the wild type protein and the cysteine-less mutant. Conclusions: The extremely low intrinsic GTPase activity of Gtr1 implies requirement for interaction with activating proteins to support its physiological function. These findings as well as the altered properties obtained by mutagenesis in the Switch regions provide insights into the function of Gtr1 and its homologues in yeast and mammals.},
  author       = {Sengottaiyan, Palanivelu and Spetea, Cornelia and Lagerstedt, Jens and Samyn, Dieter and Andersson, Michael and Ruiz-Pavon, Lorena and Persson, Bengt L.},
  issn         = {1471-2091},
  keyword      = {Gtr1,GTPase,Intrinsic tryptophan fluorescence,Rag GTPase,Cysteine,mutagenesis,Switch region},
  language     = {eng},
  publisher    = {BioMed Central},
  series       = {BMC Biochemistry},
  title        = {The intrinsic GTPase activity of the Gtr1 protein from Saccharomyces cerevisiae},
  url          = {http://dx.doi.org/10.1186/1471-2091-13-11},
  volume       = {13},
  year         = {2012},
}