FIGURE 5.
PTPD1 regulates EGFR stability. A, J82 cells were transiently transfected with siRNAPTPD1 or siRNAc. Twenty-four h after transfection, cells were serum-deprived overnight and then stimulated with EGF (100 ng/ml) for 30 min. Before fixation, cells were pulsed with mouse anti-EGFR, washed with phosphate-buffered saline, and formalin-fixed. Cells were subjected to immunostaining for PTPD1. Images were collected by confocal microscopy. A merged composite is shown on the right. B, quantification of fluorescence signals in cells subjected to pulse-chase experiments as described in A. Fluorescence values ± S.E. (error bars) were normalized to the value of control, serum-deprived cells. C, total lysates from J82 transfected cells (as in A) were subjected to immunoblot analysis with the indicated antibodies. A representative set of autoradiograms is shown. D, quantitative analysis of the experiments shown in C. A mean value ± S.E. of four independent experiments is shown. *, p < 0.01 versus control (siRNAc). P-ERK, phospho-ERK.