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Homo- and hetero-oligomerization of ammonium transporter-1 NH4 uniporters.

Ludewig, Uwe ; Wilken, Stephanie ; Wu, Binghua ; Jost, Wolfgang ; Obrdlik, Petr ; El Bakkoury, Mohamed ; Marini, Anne-Marie ; André, Bruno ; Hamacher, Tanja ; Boles, Eckhard ; von Wirén, Nicolaus ; Frommer, Wolf B. :
Homo- and hetero-oligomerization of ammonium transporter-1 NH4 uniporters.
In: The Journal of biological chemistry, 278 (46) pp. 45603-10. ISSN 0021-9258
[Artikel], (2003)

Kurzbeschreibung (Abstract)

In most organisms, high affinity ammonium uptake is catalyzed by members of the ammonium transporter family (AMT/MEP/Rh). A single point mutation (G458D) in the cytosolic C terminus of the plasma membrane transporter LeAMT1;1 from tomato leads to loss of function, although mutant and wild type proteins show similar localization when expressed in yeast or plant protoplasts. Co-expression of LeAMT1;1 and mutant in Xenopus oocytes inhibited ammonium transport in a dominant negative manner, suggesting homo-oligomerization. In vivo interaction between LeAMT1;1 proteins was confirmed by the split ubiquitin yeast two-hybrid system. LeAMT1;1 is isolated from root membranes as a high molecular mass oligomer, converted to a approximately 35-kDa polypeptide by denaturation. To investigate interactions with the LeAMT1;2 paralog, co-localizing with LeAMT1;1 in root hairs, LeAMT1;2 was characterized as a lower affinity NH4+ uniporter. Co-expression of wild types with the respective G458D/G465D mutants inhibited ammonium transport in a dominant negative manner, supporting the formation of heteromeric complexes in oocytes. Thus, in yeast, oocytes, and plants, ammonium transporters are able to oligomerize, which may be relevant for regulation of ammonium uptake.

Typ des Eintrags: Artikel
Erschienen: 2003
Autor(en): Ludewig, Uwe ; Wilken, Stephanie ; Wu, Binghua ; Jost, Wolfgang ; Obrdlik, Petr ; El Bakkoury, Mohamed ; Marini, Anne-Marie ; André, Bruno ; Hamacher, Tanja ; Boles, Eckhard ; von Wirén, Nicolaus ; Frommer, Wolf B.
Titel: Homo- and hetero-oligomerization of ammonium transporter-1 NH4 uniporters.
Sprache: Englisch
Kurzbeschreibung (Abstract):

In most organisms, high affinity ammonium uptake is catalyzed by members of the ammonium transporter family (AMT/MEP/Rh). A single point mutation (G458D) in the cytosolic C terminus of the plasma membrane transporter LeAMT1;1 from tomato leads to loss of function, although mutant and wild type proteins show similar localization when expressed in yeast or plant protoplasts. Co-expression of LeAMT1;1 and mutant in Xenopus oocytes inhibited ammonium transport in a dominant negative manner, suggesting homo-oligomerization. In vivo interaction between LeAMT1;1 proteins was confirmed by the split ubiquitin yeast two-hybrid system. LeAMT1;1 is isolated from root membranes as a high molecular mass oligomer, converted to a approximately 35-kDa polypeptide by denaturation. To investigate interactions with the LeAMT1;2 paralog, co-localizing with LeAMT1;1 in root hairs, LeAMT1;2 was characterized as a lower affinity NH4+ uniporter. Co-expression of wild types with the respective G458D/G465D mutants inhibited ammonium transport in a dominant negative manner, supporting the formation of heteromeric complexes in oocytes. Thus, in yeast, oocytes, and plants, ammonium transporters are able to oligomerize, which may be relevant for regulation of ammonium uptake.

Titel der Zeitschrift, Zeitung oder Schriftenreihe: The Journal of biological chemistry
Band: 278
(Heft-)Nummer: 46
Fachbereich(e)/-gebiet(e): Fachbereich Biologie, Biology > Pflanzenernährung und Biomasse, Plant Nutrition and Biomass
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Fachbereich Biologie, Biology
Hinterlegungsdatum: 17 Mär 2010 15:47
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