Neuhäuser, Benjamin ; Dynowski, Marek ; Mayer, Maria ; Ludewig, Uwe (2007)
Regulation of NH4+ transport by essential cross talk between AMT monomers through the carboxyl tails.
In: Plant physiology, 143 (4)
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Ammonium transport across plant plasma membranes is facilitated by AMT/Rh-type ammonium transporters (AMTs), which also have homologs in most organisms. In the roots of the plant Arabidopsis (Arabidopsis thaliana), AMTs have been identified that function directly in the high-affinity NH4+ acquisition from soil. Here, we show that AtAMT1;2 has a distinct role, as it is located in the plasma membrane of the root endodermis. AtAMT1;2 functions as a comparatively low-affinity NH4+ transporter. Mutations at the highly conserved carboxyl terminus (C terminus) of AMTs, including one that mimics phosphorylation at a putative phosphorylation site, impair NH4+ transport activity. Coexpressing these mutants along with wild-type AtAMT1;2 substantially reduced the activity of the wild-type transporter. A molecular model of AtAMT1;2 provides a plausible explanation for the dominant inhibition, as the C terminus of one monomer directly contacts the neighboring subunit. It is suggested that part of the cytoplasmic C terminus of a single monomer can gate the AMT trimer. This regulatory mechanism for rapid and efficient inactivation of NH4+ transporters may apply to several AMT members to prevent excess influx of cytotoxic ammonium.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2007 |
| Autor(en): | Neuhäuser, Benjamin ; Dynowski, Marek ; Mayer, Maria ; Ludewig, Uwe |
| Art des Eintrags: | Bibliographie |
| Titel: | Regulation of NH4+ transport by essential cross talk between AMT monomers through the carboxyl tails |
| Sprache: | Englisch |
| Publikationsjahr: | 2007 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Plant physiology |
| Jahrgang/Volume einer Zeitschrift: | 143 |
| (Heft-)Nummer: | 4 |
| Kurzbeschreibung (Abstract): | Ammonium transport across plant plasma membranes is facilitated by AMT/Rh-type ammonium transporters (AMTs), which also have homologs in most organisms. In the roots of the plant Arabidopsis (Arabidopsis thaliana), AMTs have been identified that function directly in the high-affinity NH4+ acquisition from soil. Here, we show that AtAMT1;2 has a distinct role, as it is located in the plasma membrane of the root endodermis. AtAMT1;2 functions as a comparatively low-affinity NH4+ transporter. Mutations at the highly conserved carboxyl terminus (C terminus) of AMTs, including one that mimics phosphorylation at a putative phosphorylation site, impair NH4+ transport activity. Coexpressing these mutants along with wild-type AtAMT1;2 substantially reduced the activity of the wild-type transporter. A molecular model of AtAMT1;2 provides a plausible explanation for the dominant inhibition, as the C terminus of one monomer directly contacts the neighboring subunit. It is suggested that part of the cytoplasmic C terminus of a single monomer can gate the AMT trimer. This regulatory mechanism for rapid and efficient inactivation of NH4+ transporters may apply to several AMT members to prevent excess influx of cytotoxic ammonium. |
| Fachbereich(e)/-gebiet(e): | 10 Fachbereich Biologie > Pflanzenernährung und Biomasse ?? fb10_botanik ?? 10 Fachbereich Biologie |
| Hinterlegungsdatum: | 16 Mär 2010 13:15 |
| Letzte Änderung: | 05 Mär 2013 09:32 |
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