Fig. 1

CIPK15 inhibits AMT1 activity in Xenopus oocytes. a, b Co-expression of CIPK15 inhibited NH₄⁺-triggered inward currents of AMT1;1 in Xenopus oocytes. Oocytes were injected with water only, 50 ng cRNA of AMT1;1 only, 50 ng AMT1;1 + 50 ng CIPK15, or 50 ng CIPK15 only, and perfused with NH₄Cl at the indicated concentrations (a) or (b) 0.2 mM for current recordings (a) and IV curve (b). Oocytes were voltage clamped at a − 120 mV or b − 40 mV and stepped in − 20-mV increments between − 20 and − 200 mV for 300 ms. b Currents (nA) were background subtracted (difference between currents at + 300 ms in the cRNA-injected AMT1;1 only/AMT1;1 + CIPK15/CIPK15 only and water-injected control of the indicated substrates). The data are the mean ± SE for three experiments. c TVEC traces of oocytes injected with water only, 5 ng cRNA of AMT1;1 only, or 5 ng AMT1;1 + 0.5 ng CIPK15, and perfused with NH₄Cl at the indicated concentrations. Similar results were obtained in at least three independent experiments using different batches of oocytes