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ARS Home » Research » Publications at this Location » Publication #71632
Title: UNDERSTANDING PLANT AMINO ACID TRANSPORTERS: STRUCTURE, FUNCTION, AND MOLECULAR CLONING

Author
item Bush, Daniel
item CHANG, HUI-CHU - PLANT BIOLOGY UOFI URBANA
item CHEN, LISCHAN - PLANT BIOLOGY UOFI URBANA

Submitted to: Department de Biologie Moleculaire et Structurale Centre Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 1/27/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: While plants are photoautotrophic organisms, they contain many heterotrophic tissue systems that must import sugars and amino acids to support growth and development. This resource redistribution process is a fundamental activity that allows higher plants to function as multicellular organisms. Previous work in our lab identified four amino acid transport systems based on biochemical analysis of transport activity and substrate specificity. Subsequently, we cloned one of those carriers, NAT2, by functional complementation of a yeast transport mutant with an Arabidopsis cDNA library constructed in a yeast expression vector. We have identified additional amino acid transporters in Arabidopsis using a variety of experimental approaches. One of these recent clones includes a basic amino acid transporter, LHT1. The emerging picture from our lab and others is that plants contain several families of amino acid transporters. As part of our endeavor to understand their contributions to plant growth and metabolism, we've decided to focus on a few transporters as prototypical examples of the various families. Our initial efforts have concentrated on determining the structure and function of NAT2. We are mapping the topology of the porter using c-myc epitope tags and glycosylation scanning mutagenesis. In parallel with that analysis, we've used site directed and random mutagenesis of this porter to identify essential amino acid residues and protein domains that contribute to the translocation reaction. These experiments have already provided molecular details about the structure and function of this important amino acid translocator.