Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-24410
Nagy, R; Grob, H; Weder, B; Green, P; Klein, M; Frelet-Barrand, A; Schjoerring, J K; Brearley, C; Martinoia, E (2009). The Arabidopsis ATP-binding cassette protein AtMRP5/AtABCC5 is a high affinity inositol hexakisphosphate transporter involved in guard cell signaling and phytate storage. Journal of Biological Chemistry, 284(48):33614-33622.
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Arabidopsis possesses a superfamily of ATP&-binding cassette (ABC) transporters. Among these, the multidrug resistance protein AtMRP5/AtABCC5 regulates stomatal aperture and controls plasma membrane anion channels of guard cells. Remarkably, despite the prominent role of AtMRP5 in conferring partial drought insensitivity upon Arabidopsis, we know little of the biochemical function of AtMRP5. Our phylogenetic analysis showed that AtMRP5 is closely related to maize MRP4, mutation of which confers a low inositol hexakisphosphate kernel phenotype. We now show that insertion mutants of AtMRP5 display a low inositol hexakisphosphate phenotype in seed tissue and that this phenotype is associated with alterations of mineral cation and phosphate status. By heterologous expression in yeast, we demonstrate that AtMRP5 encodes a specific and high affinity ATP&-dependent inositol hexakisphosphate transporter that is sensitive to inhibitors of ABC transporters. Moreover, complementation of the mrp5&-1 insertion mutants of Arabidopsis with a MRP5 construct driven from a guard cell-specific promoter restores the sensitivity of the mutant to ABA mediated inhibition of stomatal opening. Additionally, we show that mutation of residues of the Walker B motif prevents from restoring the multiple phenotypes associated with mrp5&-1. Our findings highlight a novel function of plant ABC transporters that may be relevant to other kingdoms. They also extend the signalling repertoire of this ubiquitous inositol polyphosphate signalling molecule.
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|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||07 Faculty of Science > Institute of Plant Biology|
|DDC:||580 Plants (Botany)|
|Deposited On:||15 Jan 2010 08:49|
|Last Modified:||28 Nov 2013 00:41|
|Publisher:||American Society for Biochemistry and Molecular Biology|
|Additional Information:||This research was originally published in "Journal of Biological Chemistry". Nagy, R. [et al.] The Arabidopsis ATP-binding cassette protein AtMRP5/AtABCC5 is a high affinity inositol hexakisphosphate transporter involved in guard cell signaling and phytate storage. J Biol Chem. 2009 Nov 27;284(48):33614-22.|
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