Characterization of the tonoplast Ca2+/H+ antiport system from maize roots.

Détails

ID Serval
serval:BIB_3876
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Characterization of the tonoplast Ca2+/H+ antiport system from maize roots.
Périodique
Plant Physiology and Biochemistry
Auteur(s)
Chanson A.
ISSN
0981-9428
Statut éditorial
Publié
Date de publication
1994
Volume
32
Numéro
3
Pages
341-346
Langue
anglais
Résumé
The tonoplast calcium Ca2+/H+ antiport system of maize (Zea mays L. cv LG 11) roots was characterized using the ''pH jump'' technique in order to avoid interference from the tonoplast proton and Ca2+ pumps. Ca2+ uptake was recorded in the presence of different inhibitors and divalent ions. Chemical modification of amino acid residues of the antiport was used to elucidate the amino acid residues participating in the Ca2+ transport activity. The Ca2+/H+ antiport activity was found to be strongly inhibited by ruthenium red and verapamil, whereas diethylstilbestrol was less effective. Vanadate, erythrosin B, cyclopiazonic acid, bafilomycin, thapsigargin, N,N'-dicyclohexylcarbodiimide (DCCD) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS) were without effect. Lanthanum and divalent ions were strongly inhibitory (Cd2+ > Mn2+ > Sr2+ > Ba2+). While reagents modifying sulfhydryl groups (N-ethylmaleimide and 5,5'-dithio-bis(2-nitrobenzoate)) did not affect the antiport activity, modification of trytophan residues (N-bromosuccinimide) was strongly inhibitory. We conclude that ruthenium red, verapamil, lanthanum and divalent cations directly inhibit Ca2+ uptake independent of the function of the proton and Ca2+ pumps. Moreover, the results of chemically modified amino acid residues suggest that sulfhydryl groups are not involved in Ca2+ transport, while tryptophan residues seem important for this translocation.
Mots-clé
CA2+/H+ ANTIPORT, CALCIUM TRANSPORTERS, CALMODULIN, PROTON PUMPS, TONOPLAST, VACUOLE, ZEA MAYS
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Création de la notice
19/11/2007 11:14
Dernière modification de la notice
20/08/2019 14:27
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