Mayer, Maria ; Schaaf, Gabriel ; Mouro, Isabelle ; Lopez, Claude ; Colin, Yves ; Neumann, Petra ; Cartron, Jean-Pierre ; Ludewig, Uwe (2006)
Different transport mechanisms in plant and human AMT/Rh-type ammonium transporters.
In: The Journal of general physiology, 127 (2)
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
The conserved family of AMT/Rh proteins facilitates ammonium transport across animal, plant, and microbial membranes. A bacterial homologue, AmtB, forms a channel-like structure and appears to function as an NH3 gas channel. To evaluate the function of eukaryotic homologues, the human RhCG glycoprotein and the tomato plant ammonium transporter LeAMT1;2 were expressed and compared in Xenopus oocytes and yeast. RhCG mediated the electroneutral transport of methylammonium (MeA), which saturated with Km = 3.8 mM at pHo 7.5. Uptake was strongly favored by increasing the pHo and was inhibited by ammonium. Ammonium induced rapid cytosolic alkalinization in RhCG-expressing oocytes. Additionally, RhCG expression was associated with an alkali-cation conductance, which was not significantly permeable to NH4+ and was apparently uncoupled from the ammonium transport. In contrast, expression of the homologous LeAMT1;2 induced pHo-independent MeA+ uptake and specific NH4+ and MeA+ currents that were distinct from endogenous currents. The different mechanisms of transport, including the RhCG-associated alkali-cation conductance, were verified by heterologous expression in appropriate yeast strains. Thus, homologous AMT/Rh-type proteins function in a distinct manner; while LeAMT1;2 carries specifically NH4+, or cotransports NH3/H+, RhCG mediates electroneutral NH3 transport.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2006 |
| Autor(en): | Mayer, Maria ; Schaaf, Gabriel ; Mouro, Isabelle ; Lopez, Claude ; Colin, Yves ; Neumann, Petra ; Cartron, Jean-Pierre ; Ludewig, Uwe |
| Art des Eintrags: | Bibliographie |
| Titel: | Different transport mechanisms in plant and human AMT/Rh-type ammonium transporters |
| Sprache: | Englisch |
| Publikationsjahr: | 2006 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | The Journal of general physiology |
| Jahrgang/Volume einer Zeitschrift: | 127 |
| (Heft-)Nummer: | 2 |
| Kurzbeschreibung (Abstract): | The conserved family of AMT/Rh proteins facilitates ammonium transport across animal, plant, and microbial membranes. A bacterial homologue, AmtB, forms a channel-like structure and appears to function as an NH3 gas channel. To evaluate the function of eukaryotic homologues, the human RhCG glycoprotein and the tomato plant ammonium transporter LeAMT1;2 were expressed and compared in Xenopus oocytes and yeast. RhCG mediated the electroneutral transport of methylammonium (MeA), which saturated with Km = 3.8 mM at pHo 7.5. Uptake was strongly favored by increasing the pHo and was inhibited by ammonium. Ammonium induced rapid cytosolic alkalinization in RhCG-expressing oocytes. Additionally, RhCG expression was associated with an alkali-cation conductance, which was not significantly permeable to NH4+ and was apparently uncoupled from the ammonium transport. In contrast, expression of the homologous LeAMT1;2 induced pHo-independent MeA+ uptake and specific NH4+ and MeA+ currents that were distinct from endogenous currents. The different mechanisms of transport, including the RhCG-associated alkali-cation conductance, were verified by heterologous expression in appropriate yeast strains. Thus, homologous AMT/Rh-type proteins function in a distinct manner; while LeAMT1;2 carries specifically NH4+, or cotransports NH3/H+, RhCG mediates electroneutral NH3 transport. |
| Fachbereich(e)/-gebiet(e): | 10 Fachbereich Biologie > Pflanzenernährung und Biomasse ?? fb10_botanik ?? 10 Fachbereich Biologie |
| Hinterlegungsdatum: | 16 Mär 2010 14:05 |
| Letzte Änderung: | 05 Mär 2013 09:32 |
| PPN: | |
| Export: | |
| Suche nach Titel in: | TUfind oder in Google |
 |
Frage zum Eintrag |
Optionen (nur für Redakteure)
 |
Redaktionelle Details anzeigen |
Drucken
Impressum