Figure 7.

Temperature dependence of NH₄⁺ currents and model for the regulation of AMT transporters by the C terminus. A, Normalized ammonium-induced currents (1 mm) at −100 mV by AtAMT1;2 (black circles) and the T472A mutant (white circles). The data were fitted with the Arrhenius equation. B, Each monomer contains an independent pathway for NH₄⁺, but the activation of all subunits within the trimer (e.g. by dephosphorylation) is essential for transport function. Conformational transitions are predicted to occur independent of further modifications in the carboxyl tail of the T472A mutant.