FIGURE 4.
Whole cell current kinetics of TRPML1 Pro substitutions. A, whole cell currents were elicited by voltage steps from −140 mV to +80 mV in increments of 20 mV in the standard extracellular (Tyrode) bath solution. Step duration = 90 ms; holding potential = 0 mV. B, no significant step current was seen for ITRPML1. C, relatively small inwardly rectifying ITRPML1-R427P. At negative potentials, ITRPML1-R427P was instantaneously activated and slowly inactivated. D–F, large strong inwardly rectifying ITRPML1-C430P (D), ITRPML1-C431P (E), and ITRPML1-V432P (F) were instantaneously activated. No obvious inactivation was seen at any voltage.