Table 1.

Coexpression with SYP121 Recovers Native AKT1-KC1 K⁺ Channel Gating Characteristics in Xenopus Oocytes

Expressed Proteins	V1/2 (mV)	δ
AKT1	−128 ±5	−1.21 ±0.03
AKT1+KC1	−208 ± 7
AKT1+KC1 +SYP121 (1:1)	−174 ± 5*	−2.18 ±0.12**
+KC1 +SYP121 (1:2)	−160 ± 2**
+KC1 +SYP121 (1:4)	−155 ± 2**

Results of joint, nonlinear, least squares fitting of K⁺ currents as described in Figure 3. For purposes of joint fittings, best results were obtained with the gating charge, δ, held in common for currents from oocytes expressing AKT1 and AKT1+KC1 and separately for currents from oocytes expressing combinations of AKT1+KC1 with SYP121. Values for the voltage giving half-maximal conductance, V_1/2, were allowed free between data sets. Data are from eight separate analysis sets. Both analyses and visual inspections showed roughly a twofold increase in δ and a saturable shift in V_1/2, with SYP121 inclusions as summarized below (means ± se, significant difference from AKT1+KC1: *, P < 0.05; **, P < 0.01), consistent with inward-rectifying K⁺ channel characteristics in the plant (see Figure 4).