IGF2 increases intracellular Ca²⁺ mobilization by PLCβ2. (A) EPCs were preincubated 6 hours with or without 50 ng/mL PTX or preincubated for 30 minutes with or without 5 mM M6P or 5 μM BAPTA-AM. Cells were stimulated with 50 ng/mL IGF2, and intracellular Ca²⁺ levels were measured. Both mRNA and protein levels of the PLC isozymes β1, β2, β3, and β4 were measured by RT-PCR (B) and Western blotting (C). (D) EPCs were transfected with nonsilencing (siCont) or PLCβ2 siRNA (siPLCβ2). After 48 hours, PLCβ2 mRNA and protein levels were measured by RT-PCR (top) and Western blotting (bottom). (E,F) EPCs were transfected as in panel D and stimulated with 50 ng/mL IGF2, and intracellular Ca²⁺ levels and adhesion were measured. (A,E) Images were viewed using an Olympus IX81-ZDC microscope with a LUCPL FLN 20×/0.45 NA lens, and processed using MetaMorph v.7.0 software. Data are the mean plus or minus SE. **P < .01 versus siCont + IGF2.