(a) Graphic representation of plasmid construction. Amino acid sequences of the linker between calmodulin (CaM) and myosin light chain (M13) peptide for YC-Nano15 and YC-Nano50 are shown. (b) Live cell images of the trophozoite stage parasite. Bright field (BF), CFP, YFP, and FRET (YFP/CFP) signals and merged image (BF-CFP-YFP). Purple to red color scale in the YFP/CFP panel represents low to high FRET efficiency (0 to 2.5). Scale bar, 2.5 μm. (c) The normalized fractional changes of the FRET signals (ΔR/R₀) are plotted against the different Ca²⁺ concentration (0, 20, 40, 60, 80, and 100 nM). The curves represent the averaged data of ten parasites from 3 independent experiments.