CEPIA4 is a genetically encoded fluorescent Ca[2+] indicator (K[[d]]] of 59μM). It is a fusion protein that contains the calmodulin-binding peptide M13, a circularly permuted fluorescent protein (based on EGFP) and calmodulin. It was derived by mutagenesis of cfGCaMP2 (itself a derivative of GCaMP2) and contains the mutations E31D, F92W and D133E relative to cfGCaMP2 (PMID:24923787). For a comparison of CEPIA4 with other CEPIA series sensors, see PMID:24923787.
