Fig. 7.

Dependence of relaxation time constants (τ) on membrane voltage (V_m) for WT hSGLT1 and mutant W291C in the absence of Na⁺. Data were obtained from the experiments in Fig. 3. The solid symbols represent the ON response when V_m was stepped from holding (V_h = −50 mV) to various test values, and the open symbols are from the subsequent OFF response when V_m was returned from test voltage to V_h. For the OFF, τ was independent of test voltage, and data shown are the mean of the 10 voltage pulses. The error bars are SEs of the fit and when absent were smaller than the size of the symbol.