Figure 3.

PIP5KIγpan siRNA attenuates intracellular Ca ²⁺ signaling. Cells loaded with fura2-AM in randomly chosen microscopic fields were ratio imaged (F₃₄₀/F₃₈₀) to obtain baseline Ca²⁺ values. Histamine was added in the absence of extracellular Ca²⁺, and the ratio image was recorded as a function of time. (A) Ca²⁺ response to 100 μM histamine (indicated by the arrow). Representative tracings for each type of RNAi are shown. Values in bar graphs are expressed as percent (mean ± SEM) of control. (B) In vivo rescue of intracellular Ca²⁺ signaling in PIP5KIγpan siRNA-treated cells by Shuttle PIP₂. Top panels are representative tracings. (Bottom) The Ca²⁺ flux of the transients elicited by the second histamine addition was plotted and 10 cells were analyzed per condition.