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. 1997 Jun 24;94(13):6904–6909. doi: 10.1073/pnas.94.13.6904

Figure 4.

Figure 4

TAP-mediated peptide translocation is inhibited in US6-transfected cells and can be overcome with IFN-γ. Streptolysin-O (Murex)-permeabilized US6 and control-transfected Pala cells (A), HeLaM (B), and HeLaM cells that had been pretreated with IFN-γ (200 unit/ml) for 48 hr (C) were incubated with an iodinated reporter peptide at 37°C for the indicated time period, and the reaction was stopped by lysis with 3% Triton X-100, as described in Materials and Methods. Translocation into the ER was assessed by binding of the glycosylated reporter peptide to concanavalin A-Sepharose beads and counting on a γ-counter. HeLaM, US6-transfected HeLaM, and US6-transfected HeLaM cells that had been pretreated with IFN-γ were analyzed for class I surface expression by flow cytometry, using the mAb w6/32 and fluorescein-conjugated rabbit anti-mouse IgG (D). The control was a nonspecific isotype-matched monoclonal antibody.