Transport Function of Rice Amino Acid Permeases (AAPs)

• Published in: Plant and cell physiology Vol. 56; no. 7; pp. 1355 - 1363
• Main Authors: Taylor, Margaret R, Reinders, Anke, Ward, John M
• Format: Journal Article
• Language: English
• Published: Japan 01-07-2015
• Subjects: Amino Acid Transport Systems - classification; Amino Acid Transport Systems - genetics; Amino Acid Transport Systems - metabolism; Amino Acids - metabolism; Animals; Biological Transport; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Isoenzymes - genetics; Isoenzymes - metabolism; Membrane Potentials; Microscopy, Confocal; Onions - cytology; Onions - enzymology; Onions - metabolism; Oocytes - metabolism; Oocytes - physiology; Oryza - enzymology; Oryza - genetics; Phylogeny; Plant Epidermis - cytology; Plant Epidermis - enzymology; Plant Epidermis - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified; Reverse Transcriptase Polymerase Chain Reaction; Substrate Specificity; Xenopus laevis; Xenopus oocytes; rice AAPs; electrophysiology; amino acid transporters
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pcv053

The transport function of four rice (Oryza sativa) amino acid permeases (AAPs), OsAAP1 (Os07g04180), OsAAP3 (Os06g36180), OsAAP7 (Os05g34980) and OsAAP16 (Os12g08090), was analyzed by expression in Xenopus laevis oocytes and electrophysiology. OsAAP1, OsAAP7 and OsAAP16 functioned, similarly to Arabidopsis AAPs, as general amino acid permeases. OsAAP3 had a distinct substrate specificity compared with other rice or Arabidopsis AAPs. OsAAP3 transported the basic amino acids lysine and arginine well but selected against aromatic amino acids. The transport of basic amino acids was further analyzed for OsAAP1 and OsAAP3, and the results support the transport of both neutral and positively charged forms of basic amino acids by the rice AAPs. Cellular localization using the tandem enhanced green fluorescent protein (EGFP)-red fluorescent protein (RFP) reporter pHusion showed that OsAAP1 and OsAAP3 localized to the plasma membrane after transient expression in onion epidermal cells or stable expression in Arabidopsis.