Fig. 4. Cellular distribution of CaM in conditions of low Ca²⁺. Bar graphs show the ratio of nucleoplasmic to cytoplasmic fluorescence (F_np/F_cytoplasm). (A) CaM distributions in glial, neuronal and HeLa cells in conditions of low Ca²⁺ concentration. Cells electroporated with 6ROX-CaM with or without 20 µg/ml WGA and 2 mM EGTA. (B) HeLa cells, electroporated with 6ROX-CaM and 6ROX-CaM1234 in 2 mM EGTA with or without 20 µg/ml WGA. 6ROX-CaM was also measured after electroporation of 10 mM EGTA instead of 2 mM EGTA. The distribution of 6ROX-CaM is shown in cells incubated with 10 µM mTrp peptide before electroporation (single bar at the right). (C) 6ROX-CaM diffusion rates in low intracellular Ca²⁺ concentration (<10 nM). HeLa cells were electroporated with 6ROX-CaM and with 20 µg/ml WGA in 2 mM EGTA and the F_np/F_cytoplasm ratio for 6ROX-CaM was recorded for 1 hour.