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Seed and vascular expression of a high-affinity transporter for cationic amino acids in Arabidopsis.

ABSTRACT: In most plants amino acids represent the major transport form for organic nitrogen. A sensitive selection system in yeast mutants has allowed identification of a previously unidentified amino acid transporter in Arabidopsis. AAT1 encodes a hydrophobic membrane protein with 14 membrane-spanning regions and shares homologies with the ecotropic murine leukemia virus receptor, a bifunctional protein serving also as a cationic amino acid transporter in mammals. When expressed in yeast, AAT1 mediates high-affinity transport of basic amino acids, but to a lower extent also recognizes acidic and neutral amino acids. AAT1-mediated histidine transport is sensitive to protonophores and occurs against a concentration gradient, indicating that AAT1 may function as a proton symporter. AAT1 is specifically expressed in major veins of leaves and roots and in various floral tissues--i.e., and developing seeds.

SUBMITTER: Frommer WB

PROVIDER: S-EPMC40291 | biostudies-other | 1995 Dec

REPOSITORIES: biostudies-other

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Seed and vascular expression of a high-affinity transporter for cationic amino acids in Arabidopsis.

Frommer W B WB Hummel S S Unseld M M Ninnemann O O

Proceedings of the National Academy of Sciences of the United States of America 19951201 26

In most plants amino acids represent the major transport form for organic nitrogen. A sensitive selection system in yeast mutants has allowed identification of a previously unidentified amino acid transporter in Arabidopsis. AAT1 encodes a hydrophobic membrane protein with 14 membrane-spanning regions and shares homologies with the ecotropic murine leukemia virus receptor, a bifunctional protein serving also as a cationic amino acid transporter in mammals. When expressed in yeast, AAT1 mediates ...[more]

PMID: 8618839

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