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Reconstitution of an electrogenic auxin transport activity mediated by Arabidopsis thaliana plasma membrane proteins
Author(s) -
Szponarski Wojciech,
Guibal Olivier,
Espuna Meriam,
Doumas Patrick,
Rossignol Michel,
Gibrat Rémy
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00200-8
Subject(s) - auxin , arabidopsis thaliana , indole 3 acetic acid , chemistry , biochemistry , membrane , efflux , biophysics , plant hormone , flux (metallurgy) , arabidopsis , biology , gene , mutant , organic chemistry
Plasma membrane proteins from Arabidopsis thaliana leaves were reconstituted into proteoliposomes and a K + diffusion potential was generated. The resulting ionic fluxes, determined in the presence of the plant hormone auxin (indole‐3 acetic acid), showed an additional electrogenic and saturable component, with a K M of 6 μM. This flux was neither detected in liposomes in the presence of indole‐3 acetic acid, nor in proteoliposomes in the presence of an inactive auxin analog and was completely inhibited by 3 μM naphtylphthalamic acid, a specific inhibitor of the auxin efflux carrier. The efficiency of the reconstituted carrier and the mechanism of its regulation by naphtylphthalamic acid are discussed.