Fig. 2

Analyses of OsHKT1;4-mediated ion transport by two electrode voltage clamp experiments using X. laevis oocytes. a, A representative confocal microscopic image of green fluorescence from oocytes injected with 3 ng of EGFP-OsHKT1;4 cRNA. b, Red fluorescence of the same oocyte shown in a, treated with the plasma membrane marker FM4-64. c, Overlay image of a and b. d, A plot profile of EGFP (green trace) and FM4-64 (red trace) fluorescence, corresponding to the boxed region in white in panel c and the white line shown in the inset image. Cyt and Ext represent the cytosolic side and the external side of the plasma membrane of the oocyte, respectively. e, Current profiles obtained using an oocyte injected with either 3 ng of EGFP-OsHKT1;4 cRNA (cell shown in a) or water in the presence of 2 mM Na⁺ with a step pulse protocol described below. Zero current levels are shown by arrows. f, Current profiles obtained using an oocyte injected with either 3 ng of OsHKT1;4 cRNA or water in the presence of 2 mM or 20 mM Na⁺ with a step pulse protocol described below. g, Current–voltage relationships of oocytes injected with 3 ng of OsHKT1;4 cRNA or water, bathed in solutions supplemented with 2 mM or 20 mM Na⁺ (n = 6-7 for OsHKT1;4 cRNA-injected oocytes and n = 3-4 for water injected oocytes, ±SE). Voltage steps from +30 to −150 mV were applied with a holding potential of −40 mV