Fig. 8.

Curcumin induces ubiquitination, internalization, and lysosomal degradation of IFNγRα. A: total cell lysates with T-84 cells treated with 75 μM curcumin for 0–4 h were immunoprecipitated (IP) with control IgG or anti-IFNγRα antibody. The precipitated protein was analyzed with ubiquitin-specific or IFNγRα-specific antibody (loading control) by Western blotting (WB). B: cell surface biotinylation performed in T-84 cells treated with 75 μM curcumin at 37°C (1–8 h; left) or 4°C (1 h; right). GAPDH or IFNγRα were analyzed in the total cell lysate as input controls. C: degradation of total cellular IFNγRα protein in T-84 cells treated with 75 μM curcumin for 1–8 h. Analysis was performed in the absence (left) or presence of the lysosomal inhibitor bafilomycin A1 (right; see materials and methods).