SHP2 regulates the phosphorylation and internalization of CDCP1.

<p><b>A.</b> HeLa cells stably transfected with an empty vector or with a WT-CDCP1 construct were stably transfected with a SHP2-targeting shRNA (D1 or D2), as indicated. Total cell lysates were prepared and analyzed by western blotting with the antibodies indicated. <b>B.</b> Stable HeLa-CDCP1 and HeLa-CDCP1-shSHP2 D1 cell lines (described above and in the experimental procedures) were first incubated with an anti-CDCP1 antibody at 4°C. The cells were washed and incubated at 37°C for the times indicated, to allow internalization of the CDCP1-antibody complexes. The cells were then incubated again at 4°C with the appropriate secondary antibody, and the amount of CDCP1 remaining at the cell surface was analyzed by flow cytometry. The results are indicated as a percentage of membrane CDCP1 ± SEM for three independent experiments. ns: p > 0.05 *: p = 0.03; ****: p = 10^–4 in non-parametric Student's <i>t</i> tests. The data shown are representative of at least three independent experiments performed in triplicate.