Skip to main content
. Author manuscript; available in PMC: 2018 Jun 22.
Published in final edited form as: Cell. 2011 Mar 4;144(5):703–718. doi: 10.1016/j.cell.2011.02.003

Figure 2. PTPN12 Interacts with and Inhibits the HER2/EGFR Signaling Axis.

Figure 2

(A and B) Tyrosine phosphoproteins regulated by PTPN12. HMECs expressing an inducible PTPN12-shRNA were quantified in the presence and absence of PTPN12 for tyrosine-phosphorylated peptides using a quantitative proteomic approach (described in Experimental Procedures). Interactions between the 69 PTPN12-regulated phosphoproteins were analyzed via (A) Ingenuity and (B) the HPRD.

(C) HER2 and EGFR RTKs interact with PTPN12 in HMECs. The left panel shows the experimental design of the BiFC system. PTPN12 was fused with the N terminus of YFP, and RTKs were fused with the C terminus of YFP. HMECs were transduced with retroviruses expressing PTPN12-N-YFP and individual RTK-C-YFP cDNAs. In the right panel the interaction between PTPN12 and HER family RTKs was assessed by cellular fluorescence. Asterisk indicates p < 0.01.

(D) Substrate-trapping PTPN12 mutant displays increased interaction with HER2. Breast cancer cells expressing PTPN12-WT-N-YFP or mutant PTPN12-C231S-N-YFP in combination with HER2-C-YFP were analyzed for cellular fluorescence.

(E) PTPN12 loss of function elicits hyperactivation of HER2, EGFR, and a MAPK-signaling cascade. HMECs engineered with an inducible PTPN12-shRNA were cultured ± dox for 3 days, starved of growth factors, and analyzed for levels of the indicated total and phosphorylated proteins by western.

(F) PTPN12 suppresses HER2, EGFR, and MAPK signaling. HMECs engineered with an inducible PTPN12-cDNA were cultured and analyzed as in (E). Error bars represent standard error.