G-CatchER⁺ is an engineered green fluorescent Ca[2+] indicator that was generated by introducing a single Ca[2+] binding site with negatively charged residues into the EGFP fluorescent protein, along with a number of other mutations designed to overcome folding limitations and to increase dynamic range. G-CatchER⁺ is designed to report rapid local endoplasmic reticulum Ca[2+] dynamics (FBrf0248336).