Phosphoprotein Phosphatase 1 Is Required for Extracellular Calcium-Induced Keratinocyte Differentiation

Figure 9

Knockdown of E-cadherin/catenins or PLC-γ1 blocks calcium-induced PIP5K1α activity. Cultured human keratinocytes were treated with siRNA for E-cadherin, β-catenin, p120, and PLC-γ1 for 72 hours and then with calcium for 5 min. Cells were harvested and total cell lysates were isolated for PIP5K1α activity assay. (a) The autoradiograph shown is from a representative experiment repeated thrice with three separate siRNA treatments. (b) The PIP₂ signal intensities were quantitated by Image Pro Plus Software and normalized to band intensities of PIP5K1α in the corresponding western blot. Results are expressed as percentages of the values in the control lane (the presence of 0.03 mM calcium and control siRNA). Data are expressed as mean ± SD of three separate experiments, (significantly different from the control in the presence of 0.03 mM calcium and siRNA).

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