Fig. 6

Application of monSTIM1 variants in neurons. A Top: Schematic of the experiment. AAV-compatible monSTIM1 variants are expressed under the control of a CaMKIIα promoter targeted to the hippocampal CA1 region. Bottom: Mice were illuminated with blue LED light via a customized transcranial light illumination system and perfused for immunohistochemistry. B Schematic displaying the areas used for the quantification of active neurons expressing cFos and monSTIM1 variants in the CA1 region. Two AAV-compatible monSTIM1 variants—AAV-CaMKIIα-FLAG-monSTIM1 and AAV-CaMKIIα-EGFP-STIM1(318–450)—were used. Representative images showing CA1 neurons expressing FLAG-monSTIM1. Blue, DAPI; Green, FLAG; Magenta, NeuN. Scale bar, 50 μm. C Representative images showing cFos-positive cells expressing each monSTIM1 variants, with or without non-invasive light delivery, and EGFP (control). Scale bar, 50 μm. D Quantification of cFos-positive cells expressing FLAG-monSTIM1. E Quantification of cFos-positive cells expressing EGFP-STIM1(318–450). EGFP: n = 4; FLAG-monSTIM1 (-Light): n = 5; FLAG-monSTIM1 (+ Light): n = 5; EGFP-CRY2-STIM1(318–450) (-Light): n = 5; EGFP-CRY2-STIM1(318–450) (+ Light): n = 6 mice. Data are presented as means ± SEM (*p < 0.05, **p < 0.01; one-way ANOVA followed by Holm-sidak’s multiple comparison test); ns, not significant (p > 0.05)