jGCaMP7s is a genetically encoded fluorescent Ca[2+] indicator. It consists of the calmodulin-binding peptide M13, a circularly permuted green fluorescent protein and calmodulin. jGCaMP7s contains the following mutations relative to GCaMP6s : A52V and A317L. jGCaMP7s is considered the most sensitive of the '7' series of jGCaMP sensors (7b, 7c, 7f, 7s), as well as very bright (FBrf0242918).