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. 2012 Nov 5;109(47):19226–19231. doi: 10.1073/pnas.1211491109

Fig. 1.

Fig. 1.

PTP1B regulates the ligand-inducible endocytosis of IFNAR1. (A) Degradation of IFNAR1 in human 293-IL-1RI cells treated with CHX (20 µg/mL) and either PBS, IFN-α (1,000 U/mL), or IL-1β (2 ng/mL) for indicated times. (B) Phosphorylation and ubiquitination of IFNAR1 immunopurified from 293-IL-1RI cells treated with PBS, IFN-α (1,000 U/mL), or IL-1β (2 ng/mL) for 10 min were analyzed by immunoblotting using the indicated antibodies. (C) Internalization rate of endogenous IFNAR1 in cells treated with PBS (diamonds), IFN-α (1,000 U/mL; squares), or IL-1β (2 ng/mL; circles) for indicated times was assessed from three independent experiments (each in six replicates) and depicted as average + SEM. (D) The interaction between endogenous IFNAR1 and PTP1B in 293-IL-1RI cells stimulated with either IFN-α (1,000 U/mL) or IL-1β (2 ng/mL) for 10 min was assessed by immunoprecipitation–immunoblotting using indicated antibodies. Levels of PTP1B in whole cell lysates (WCLs) were also analyzed. (E) Internalization of endogenous IFNAR1 in 293-IL-1RI cells treated with IFN-α (1,000 U/mL) in the presence of vehicle (DMSO; gray diamonds) or PTP1B inhibitors CinnGel2Me (10 µm; black triangles) or sodium stibogluconate (SSG; 10 µg/mL; black squares). (F) Internalization of endogenous IFNAR1 in IFN-α–treated 293-IL-1RI cells transfected with empty vector (Vec; gray diamonds) or constructs for expression of PTP1B (WT, black squares; D181A mutant, open circles). (G) Internalization of endogenous IFNAR1 in IFN-α–treated 293-IL-1RI cells that received control shRNA (black diamonds) or shRNA against PTP1B (shP1B; gray squares). Inset shows the effect of these shRNAs on the levels of PTP1B (Upper) or β-actin (Lower).