Fig. 2: OLPVR1 is expressed intracellularly and activates surface CaCCs through release of intracellular Ca²⁺.

a Surface expression of HiBit-tagged OLPVR1_HB compared to ChR2_HB measured using XenoGlo technique. OLPVR1, in contrast with ChR2, is not expressed at the surface membrane of oocytes. Mean luminescence recorded in oocytes injected with 7.5 ng RNA coding for OLPVR1_HB and ChR2_HB before (blue) and after (red) membrane permeabilization. The OLPVR1 surface value is 2360 ± 700 RLUs. The numbers of oocytes batches are in parentheses (Error bars, SEM). **P = 0.007, ****P < 0.0001 two-way ANOVA with Sidak’s post hoc test (DF = 60). b Photocurrents elicited by successive 10-s illuminations separated by a 40-s dark interval. Oocytes coexpressing OLPVR1 (30 ng RNA) and Gq-coupled muscarinic M3 receptor (2.5 ng) were bathed in ND96 0Ca solution. c, d Between the 2 illuminations, activation of M3 by ACh (5 µM; 30 s) induced Ca²⁺ release and large transient CaCC currents. Panel d is an enlarged version of c, showing a drastic reduction of the second photocurrent. e Average ratios of OLPVR1 peak current induced by the second illumination (Peak 2) over that of the first (Peak 1) with and without ACh application in between. Numbers of oocytes are in parentheses (Error bars, SEM). f Photocurrents at +60 mV in ND96 solution from oocytes expressing OLPVR1 (7.5 ng RNA) before (Control) and after 10’ incubation with 10 µM YM-254890. g, h Representative photocurrents at +60 mV in ND96 (g) or 49 Ca²⁺(h) solution from oocytes expressing OLPVR1 (7.5 ng RNA) before (Control) and after 60’ incubation with 100 µM 2-APB. Statistics are shown in Supplementary Fig. 1. Source data are provided as a Source Data file.