Fig. 6. Close temporal relationship between the BzATP-induced rise of [Ca²⁺]_i and PKC translocation. (A) Simultaneous imaging of [Ca²⁺]_i using the fluorescent Ca²⁺ indicator dye Fura-red (red) and PKC-EGFP (green). Fura-red intensity (F) decreases with the rise of [Ca²⁺]_i, so data are expressed as the ratio of initial intensity (F₀) to F for a region of interest in the cytosol. BzATP was added at 50 seconds (vertical broken line) and PKC translocation follows the rise in [Ca²⁺]_i. Data are representative of seven out of ten cells tested. (B,C) BzATP induced a repetitive translocation of PKC-EGFP in some osteoclast-like cells. An osteoclast-like cell was stimulated with BzATP (150 µM, applied at 25 seconds) as indicated, inducing repetitive translocation of PKC between the cytosol and membrane. A confocal slice through the cell is shown in B, with membrane localization plotted in C for the same cell. Responses are representative of repetitive PKC translocation seen in 18 out of 68 osteoclast-like cells that responded to BzATP.