Highly Dynamic and Sensitive NEMOer Calcium Indicators for Imaging ER Calcium Signals in Excitable Cells

Gu, W.; Chen, J.-H.; Zhang, Y.; Wang, Z.; Li, J.; Wang, S.; Zhang, H.; Jiang, A.; Zhong, Z.; Zhang, J.; Xi, C.; Hou, T.; Gill, D. L.; Li, D.; Mu, Y.; Wang, S.-Q.; Tang, A.-H.; Wang, Y.

doi:10.1101/2024.03.08.583332

bioRxiv · 10.1101/2024.03.08.583332

Highly Dynamic and Sensitive NEMOer Calcium Indicators for Imaging ER Calcium Signals in Excitable Cells

Gu, W.·Chen, J.-H.·Zhang, Y.·Wang, Z.·Li, J.·Wang, S.·Zhang, H.·Jiang, A.·Zhong, Z.·Zhang, J.·Xi, C.·Hou, T.·Gill, D. L.·Li, D.·Mu, Y.·Wang, S.-Q.·Tang, A.-H.·Wang, Y.

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Abstract

Endoplasmic/sarcoplasmic reticulum (ER/SR) sits at the heart of the calcium (Ca2+) signaling machinery, yet current genetically encoded Ca2+ indicators (GECIs) lack the ability to detect elementary Ca2+ release events from ER/SR, particularly in muscle cells. Here we report a set of organellar GECIs, termed NEMOer, to efficiently capture ER Ca2+ dynamics with increased sensitivity and responsiveness. Compared to G-CEPIA1er, NEMOer indicators exhibit dynamic ranges that are an order of magnitude larger, which enables up to 5-fold more sensitive detection of Ca2+ oscillation in both non-excitable and excitable cells. The ratiometric version further allows super-resolution monitoring of local ER Ca2+ homeostasis and dynamics. Notably, the NEMOer-f variant enabled the inaugural detection of Ca2+ blinks, elementary Ca2+ releasing signals from the SR of cardiomyocytes, as well as in vivo spontaneous SR Ca2+ releases in zebrafish. In summary, the highly dynamic NEMOer sensors expand the repertoire of organellar Ca2+ sensors that allow real-time monitoring of intricate Ca2+ dynamics and homeostasis in live cells with high spatiotemporal resolution.

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Gu, W., Chen, J.-H., Zhang, Y., Wang, Z., Li, J., Wang, S., Zhang, H., Jiang, A., Zhong, Z., Zhang, J., Xi, C., Hou, T., Gill, D. L., Li, D., Mu, Y., Wang, S.-Q., Tang, A.-H., Wang, Y.. 2024-03-09. Highly Dynamic and Sensitive NEMOer Calcium Indicators for Imaging ER Calcium Signals in Excitable Cells. https://doi.org/10.1101/2024.03.08.583332

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