Extended Data Fig. 3: Improvements to ASAP4.2.
From: A positively tuned voltage indicator for extended electrical recordings in the brain
(A) Mean fluorescent responses of ASAP4.2 F413X variants to a series of voltage steps from –120 to +50 mV, from a holding potential of –70 mV in voltage-clamped HEK293A cells. Error bars represent SEM. Only proline was excluded due to expression issues. (B) F/Fmax a 23 °C for ASAP4.2 and the three best derivatives. Error bars represent SEM centered on measured mean values; curved lines represent Boltzmann distributions fit to the measured mean values. (C) F/Fmax at 23 and 37 °C for ASAP3, ASAP4b, and ASAP4e. Error bars represent SEM. (D) F/Fmax in HEK cells under 2-photon illumination at 940 nm for ASAP3, ASAP4b, and ASAP4e imaged at 23 °C. n = 73 for ncpASAP4b, 81 for ASAP3, 126 for ASAP4b, and 76 for ASAP4e. Bars represent mean ± SEM. All GEVIs were significantly different from each other (p < 0.0001), except for ASAP4b vs. ASAP4e (p = 0.8108) by Dunnett’s multiple comparison test. (E) One-photon excitation and emission spectra measured for ASAP3, ASAP4b, and ASAP4e in HEK293-Kir2.1 cells at 23 °C. (F) Two-photon excitation spectra measured with 2-nm spectral intervals from HEK293-Kir2.1 cells. Peaks were at 938 nm. n = 52 for ncpASAP4b, 57 for ASAP3, 57 for ASAP4b, and 44 for ASAP4e.
