Effects of PLC-β1 or PLC-β4 overexpression on Ca²⁺ and IP₃ dynamics evoked by histamine stimulation.

<p>(A) Western blotting analyses of cell lysates prepared from HeLa cells transfected with PLC-β1-IRES-mRFP (lane 2) or PLC-β4-IRES-mRFP (lane 4). Non-transfected cells were used as controls (lanes 1 and 3). (B) Representative traces of Indo-5F signal changes (F/F₀; top) and IRIS-1 signal changes (ΔR/R₀; bottom) in transfected cells stimulated with 3 µM histamine. The plasmid DNAs used to transfect the cells are shown on the left. The horizontal broken lines indicate the baseline levels of IRIS-1 and Indo-5F signals. The vertical broken lines indicate the onsets of stimulation. (B–D) Histograms for the inverse time constants for exponential decay of the Ca²⁺ oscillation amplitude (B), Ca²⁺ oscillation frequencies (C), and integrated IP₃ signals (D) in cells expressing mRFP (top row), PLC-β1 and mRFP (second row), and PLC-β4 and mRFP (third row). The means ± SD are shown at the bottom. The numbers of cells measured are shown in parentheses. Statistical analyses were performed by one-way ANOVA followed by Scheffe’s multiple comparison test. **P<0.01, vs. the values in IRES-mRFP transfected cells.