title: AtPTR4 and AtPTR6 are differentially expressed, tonoplast-localized members of the peptide transporter/nitrate transporter 1 (PTR/NRT1) family.
abstract: Members of the peptide transporter/nitrate transporter 1 (PTR/NRT1) family in plants transport a variety of substrates like nitrate, di- and tripepetides, auxin and carboxylates. We isolated two members of this family from Arabidopsis, AtPTR4 and AtPTR6, which are highly homologous to the characterized di- and tripeptide transporters AtPTR1, AtPTR2 and AtPTR5. All known substrates of members of the PTR/NRT1 family were tested using heterologous expression in Saccharomyces cerevisiae mutants and oocytes of Xenopus laevis, but none could be identified as substrate of AtPTR4 or AtPTR6. AtPTR4 and AtPTR6 show distinct expression patterns, while AtPTR4 is expressed in the vasculature of the plants, AtPTR6 is highly expressed in pollen and during senescence. Phylogenetic analyses revealed that AtPTR2, 4 and 6 belong to one clade of subgoup II, whereas AtPTR1 and 5 are found in a second clade. Like AtPTR2, AtPTR4-GFP and AtPTR6-GFP fusion proteins are localized at the tonoplast. Vacuolar localization was corroborated by co-localization of AtPTR2-YFP with the tonoplast marker protein GFP-AtTIP2;1 and AtTIP1;1-GFP. This indicates that the two clades reflect different intracellular localization at the tonoplast (AtPTR2, 4, 6) and plasma membrane (AtPTR1, 5), respectively.
authors: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland.
authors: Annett
authors: A
authors: Weichert
authors: Christopher
authors: C
authors: Brinkmann
authors: Nataliya Y
authors: NY
authors: Komarova
authors: Daniela
authors: D
authors: Dietrich
authors: Kathrin
authors: K
authors: Thor
authors: Stefan
authors: S
authors: Meier
authors: Marianne
authors: M
authors: Suter Grotemeyer
authors: Doris
authors: D
authors: Rentsch
mesh_terms: D000818:Animals; D027321:Anion Transport Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D061245:Axenic Culture; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D016366:Open Reading Frames; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000235:genetics / Q000378:metabolism; D011523:Protoplasts / Q000166:cytology / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism; D014982:Xenopus laevis / Q000235:genetics / Q000378:metabolism
chemical_list: D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; C101492:NRT1.1 protein, Arabidopsis; C098241:PTR2 protein, Arabidopsis; D010940:Plant Proteins; D018749:RNA, Plant; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins