Table 1. Coexpressing VAMP721 with the KAT1 K+ Channel in Xenopus Oocytes Suppresses the Current Amplitude and Alters Channel Gating.
| V1/2 (mV) | gmax (ms) | δ | |
|---|---|---|---|
| KAT1 | −126.1 ± 0.7 | 1.47 ± 0.01 | −1.70 ± 0.05 |
| KAT1+VAMP723 (1:4) | −128.5 ± 0.6 | ||
| KAT1+VAMP721 (1:1) | −126.7 ± 0.7 | ||
| KAT1+VAMP721 (1:2) | −136.8 ± 1.0* | 1.12 ± 0.02 | |
| KAT1+VAMP721 (1:4) | −139.7 ± 1.7* | 0.58 ± 0.01 | |
| KAT1+VAMP721 (1:8) | −141.5 ± 1.6* |
Parameter values are results of joint, nonlinear least-squares fitting of K+ currents in Figure 3. Fittings were carried out with the gating charge, δ, held in common, and values for the voltage giving half-maximal conductance V1/2 and conductance maximum gmax were allowed to vary between data sets. Data for KAT1 and KAT1+VAMP721 (1:1) were visually indistinguishable; therefore, gmax values were fitted jointly to simplify analysis. Similarly, gmax values for KAT1+VAMP721 (1:4) and KAT1+VAMP721 (1:8) were fitted jointly. Data are from seven or more separate experiments for each construct combination and are given as means ± se. Significance for V1/2 as the difference from KAT1 expressed alone at *P < 0.01.