Arabidopsis POLYOL TRANSPORTERS5, a New Member of the Monosaccharide Transporter-Like Superfamily, Mediates${\rm H}^{+}\text{-Symport}$of Numerous Substrates, Including myo-Inositol, Glycerol, and Ribose
Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Arabidopsis POLYOL TRANSPORTERS5, a New Member of the Monosaccharide Transporter-Like Superfamily, Mediates${\rm H}^{+}\text{-Symport}$of Numerous Substrates, Including myo-Inositol, Glycerol, and Ribose
Erschienen:
American Society of Plant Biologists, 2005
Erschienen in:The Plant Cell
Sprache:
Englisch
ISSN:
1040-4651
Entstehung:
Anmerkungen:
Beschreibung:
<p>Six genes of the Arabidopsis thaliana monosaccharide transporter-like (MST-like) superfamily share significant homology with polyol transporter genes previously identified in plants translocating polyols (mannitol or sorbitol) in their phloem (celery [Apium graveolens], common plantain [Plantago major], or sour cherry [Prunus cerasus]). The physiological role and the functional properties of this group of proteins were unclear in Arabidopsis, which translocates sucrose and small amounts of raffinose rather than polyols. Here, we describe POLYOL TRANSPORTERS (AtPLT5), the first member of this subgroup of Arabidopsis MST-like transporters. Transient expression of an AtPLT5-green fluorescent protein fusion in plant cells and functional analyses of the AtPLT5 protein in yeast and Xenopus oocytes demonstrate that AtPLT5 is located in the plasma membrane and characterize this protein as a broad-spectrum<tex-math>${\rm H}^{+}\text{-Symporter}$</tex-math>for linear polyols, such as sorbitol, xylitol, erythritol, or glycerol. Unexpectedly, however, AtPLT5 catalyzes also the transport of the cyclic polyol myo-inositol and of different hexoses and pentoses, including ribose, a sugar that is not transported by any of the previously characterized plant sugar transporters. RT-PCR analyses and AtPLT5 promoter-reporter gene plants revealed that AtPLT5 is most strongly expressed in Arabidopsis roots, but also in the vascular tissue of leaves and in specific floral organs. The potential physiological role of AtPLT5 is discussed.</p>