title: Expression and transport function of the glutamate transporter EAAC1 in Xenopus oocytes is regulated by syntaxin 1A.
abstract: The function of several membrane proteins is regulated by interaction with the SNARE protein syntaxin 1A; this includes regulation of GAT1, the transporter for the dominating inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Here we demonstrate that also EAAC1, the transporter for the dominating excitatory neurotransmitter, is down-regulated by interaction with syntaxin 1A. This is shown by coexpression of EAAC1 and syntaxin 1A in Xenopus oocytes. Total EAAC1 expression is not significantly affected by the coexpression of syntaxin 1A, but more proteins become targeted to the membrane as demonstrated by biotinylation. Colocalization by coimmunoprecipitation suggests direct interaction between the two proteins. In contrast to the number of transporters, the glutamate transport activity becomes reduced, and even stronger inhibition is observed for the EAAC1-mediated conductance uncoupled from glutamate translocation. We conclude that the interaction of syntaxin 1A with EAAC1 particularly disrupts the structure of the conductance pathway of EAAC1.
authors.affiliation: Max-Planck Guest Laboratory at the Institute of Biochemistry and Cell Biology, CAS, Shanghai, China.
authors.forename: Yani
authors.initials: Y
authors.lastname: Zhu
authors.forename: Jian
authors.initials: J
authors.lastname: Fei
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schwarz
mesh_terms: D027322:Amino Acid Transport System X-AG / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D000954:Antigens, Surface / Q000096:biosynthesis / Q000494:pharmacology*; D015153:Blotting, Western / Q000379:methods; D002712:Chlorides / Q000494:pharmacology; D003001:Cloning, Molecular / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects*; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000528:radiation effects; D008845:Microinjections / Q000379:methods; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000494:pharmacology*; D009865:Oocytes / Q000378:metabolism*; D018408:Patch-Clamp Techniques / Q000379:methods; D021381:Protein Transport / Q000187:drug effects; D027981:Symporters / Q000494:pharmacology / Q000502:physiology*; D050827:Syntaxin 1; D014316:Tritium / Q000378:metabolism; D014981:Xenopus
chemical_list: D027322:Amino Acid Transport System X-AG; D000954:Antigens, Surface; D002712:Chlorides; D050491:Glutamate Plasma Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D027981:Symporters; D050827:Syntaxin 1; D014316:Tritium; D018698:Glutamic Acid