The activity of TRPV1 is dependent on phosphoinositides.

<p>(A) Confocal images of cells expressing PJ-Dead (<i>top</i>), PJ-Sac (<i>middle</i>), INPP5E (<i>middle</i>), or PJ (<i>bottom</i>) with LDR and respective biosensors for PI(4)P (Osh1-PH-GFP) or PI(4,5)P₂ (PLCδ1-PH-GFP). Images before and after the addition of rapamycin (1 μM) for 60 s (Scale bar, 5 μm). (B) Cytosolic fluorescence intensities of RFP (<i>red</i>) and GFP (<i>green</i>) for the cells in (A). The values of the Y-axis use an arbitrary unit. Cells expressing PJ-Dead (<i>top</i>), PJ-Sac (<i>middle</i>), INPP5E (<i>middle</i>), or PJ (<i>bottom</i>) (n = 3, respectively). (C) TRPV1 currents triggered by prolonged extracellular pH drop to 5.0 for 150 s. Rapamycin (1 μM) was co-applied for 90 s during the acid stimuli. Amiloride (300 μM) was pretreated for 30 s before the pH pulse. Black dashed line indicates the zero current level. Red dashed line indicates the point of rapamycin application. (D) Percentage of current decrease in (C) during 45 s of acidification before (grey) and after (red) rapamycin addition (n = 12 for PJ-Dead; n = 14 for PJ-Sac; n = 12 for INPP5E; n = 10 for PJ). ** <i>P</i> < 0.01 and *** <i>P</i> < 0.001, with two-way ANOVA followed by Bonferroni post-hoc test and one-way ANOVA followed by Bonferroni post-hoc test. Data are mean ± SEM.