A genetically encoded far-red fluorescent calcium ion biosensor derived from a biliverdin-binding protein.

ABSTRACT: Far-red and near-infrared (NIR) genetically encoded calcium ion (Ca²⁺ ) indicators (GECIs) are powerful tools for in vivo and multiplexed imaging of neural activity and cell signaling. Inspired by a previous report to engineer a far-red fluorescent protein (FP) from a biliverdin (BV)-binding NIR FP, we have developed a far-red fluorescent GECI, designated iBB-GECO1, from a previously reported NIR GECI. iBB-GECO1 exhibits a relatively high molecular brightness, an inverse response to Ca²⁺ with ΔF/F_min  = -13, and a near-optimal dissociation constant (K_d ) for Ca²⁺ of 105 nM. We demonstrate the utility of iBB-GECO1 for four-color multiplexed imaging in MIN6 cells and five-color imaging in HEK293T cells. Like other BV-binding GECIs, iBB-G

SUBMITTER: Hashizume R 

PROVIDER: S-EPMC9518226 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature