This Article Full Text Full Text (PDF) All Versions of this Article: 137/1/117    most recent pp.104.055079v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (20) Citing Articles via Google Scholar Google Scholar Articles by Grallath, S. Articles by Rentsch, D. Search for Related Content PubMed PubMed Citation Articles by Grallath, S. Articles by Rentsch, D. Agricola Articles by Grallath, S. Articles by Rentsch, D.

CELL BIOLOGY AND SIGNAL TRANSDUCTION

The AtProT Family. Compatible Solute Transporters with Similar Substrate Specificity But Differential Expression Patterns¹

Institute of Plant Sciences, University of Bern, 3013 Bern, Switzerland (S.G., A.M., C.G, M.S., D.R); Zentrum für Molekularbiologie der Pflanzen, Plant Physiology, 72076 Tübingen, Germany (T.W.); and Université de Neuchâtel, Laboratoire de Biochimie, 2007 Neuchâtel, Switzerland (J.-M.N.)

Proline transporters (ProTs) mediate transport of the compatible solutes Pro, glycine betaine, and the stress-induced compound -aminobutyric acid. A new member of this gene family, AtProT3, was isolated from Arabidopsis (Arabidopsis thaliana), and its properties were compared to AtProT1 and AtProT2. Transient expression of fusions of AtProT and the green fluorescent protein in tobacco (Nicotiana tabacum) protoplasts revealed that all three AtProTs were localized at the plasma membrane. Expression in a yeast (Saccharomyces cerevisiae) mutant demonstrated that the affinity of all three AtProTs was highest for glycine betaine (K_m = 0.1–0.3 mM), lower for Pro (K_m = 0.4–1 mM), and lowest for -aminobutyric acid (K_m = 4–5 mM). Relative quantification of the mRNA level using real-time PCR and analyses of transgenic plants expressing the -glucuronidase (uidA) gene under control of individual AtProT promoters showed that the expression pattern of AtProTs are complementary. AtProT1 expression was found in the phloem or phloem parenchyma cells throughout the whole plant, indicative of a role in long-distance transport of compatible solutes. -Glucuronidase activity under the control of the AtProT2 promoter was restricted to the epidermis and the cortex cells in roots, whereas in leaves, staining could be demonstrated only after wounding. In contrast, AtProT3 expression was restricted to the above-ground parts of the plant and could be localized to the epidermal cells in leaves. These results showed that, although intracellular localization, substrate specificity, and affinity are very similar, the transporters fulfill different roles in planta.

² Present address: Max-Planck-Institut für Biochemie, Zelluläre Biochemie, Am Klopferspitz 18a, 82152 Martinsried, Germany.

³ Present address: University of Cambridge, Department of Biochemistry, Building O, Downing Site, Cambridge CB2 1QW, UK.

Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.104.055079.

^* Corresponding author; e-mail doris.rentsch{at}ips.unibe.ch; fax 41–31–631–4942.

Received October 15, 2004; returned for revision November 5, 2004; accepted November 22, 2004.

This article has been cited by other articles:

				C. Paungfoo-Lonhienne, P. M. Schenk, T. G. A. Lonhienne, R. Brackin, S. Meier, D. Rentsch, and S. Schmidt Nitrogen affects cluster root formation and expression of putative peptide transporters J. Exp. Bot., July 1, 2009; 60(9): 2665 - 2676. [Abstract] [Full Text] [PDF]

				N. Y. Komarova, K. Thor, A. Gubler, S. Meier, D. Dietrich, A. Weichert, M. Suter Grotemeyer, M. Tegeder, and D. Rentsch AtPTR1 and AtPTR5 Transport Dipeptides in Planta Plant Physiology, October 1, 2008; 148(2): 856 - 869. [Abstract] [Full Text] [PDF]

				J. A. Khan, Q. Wang, R. D. Sjolund, A. Schulz, and G. A. Thompson An Early Nodulin-Like Protein Accumulates in the Sieve Element Plasma Membrane of Arabidopsis Plant Physiology, April 1, 2007; 143(4): 1576 - 1589. [Abstract] [Full Text] [PDF]

				E. Mazzucotelli, A. Tartari, L. Cattivelli, and G. Forlani Metabolism of {gamma}-aminobutyric acid during cold acclimation and freezing and its relationship to frost tolerance in barley and wheat J. Exp. Bot., November 1, 2006; 57(14): 3755 - 3766. [Abstract] [Full Text] [PDF]

				A. Meyer, S. Eskandari, S. Grallath, and D. Rentsch AtGAT1, a High Affinity Transporter for {gamma}-Aminobutyric Acid in Arabidopsis thaliana J. Biol. Chem., March 17, 2006; 281(11): 7197 - 7204. [Abstract] [Full Text] [PDF]

				T. A. Cuin and S. Shabala Exogenously Supplied Compatible Solutes Rapidly Ameliorate NaCl-induced Potassium Efflux from Barley Roots Plant Cell Physiol., December 1, 2005; 46(12): 1924 - 1933. [Abstract] [Full Text] [PDF]