The TRPV4P19S allele is hypofunctioning in vitro. Time courses for whole-cell currents at −100 mV and +100 mV in HEK293 cells transfected with human TRPV4WT (A) and TRPV4P19S (B) exposed to 15% hypotonicity and then 4α-phorbol 12,13-didecanoate (4αPDD; 10 μM). (C and D) Corresponding whole-cell current/voltage relationships recorded at the times indicated by the color-coded boxes in A and B, respectively. (E) Mean current density (expressed as pA/pF at +100 mV) of TRPV4WT (WT) and TRPV4P19S (P19S) and of an equimolar ratio of the 2 alleles (WT:P19S) upon exposure to mild (i.e., 15%; Left) and more pronounced (i.e., 30%; Right) hypotonicity. (F) Representative current/voltage relationship at peak (maximum) currents from TRPV4WT and TRPV4P19S transfectants loaded with 156 nM epoxyeicosatrienoic acid (EET) in the pipette solution, and the mean responses (G). Data are expressed as the mean ± SEM of the number of experiments shown in brackets. *P < 0.05, relative to other transfectants in presence of 15% hypotonicity, via one-way ANOVA and Tukey post hoc.