Fig. 5

2-thio-6-azauridine dose not affect lysosomal-dependent degradation. a Models for the ubiquitin-mediated down-regulation of BST-2 by Vpu and for the ubiquitin-mediated down-regulation of IFNAR1 upon treatment of cells with IFN-α. Left panel Vpu interacts with BST-2 via the transmembrane domain and then induces BST-2 ubiquitination through the recruitment of β-TrCP2-containing E3 ubiquitin ligase complex, thus targeting the ubiquitinated proteins to lysosomal degradation. Right panel Treatment with IFN-α promotes phosphorylation of IFNAR1. Phosphorylated IFNAR1 recruits β-TrCP2-containing E3 ubiquitin ligase complex and is ubiquitinated, then ubiquitinated proteins are degraded through lysosomal pathway. b Effect of 2-thio-6-azauridine on IFN-induced down-regulation of IFNAR1. HeLa cells were transfected with IFNAR1 expressing plasmid pcDNA3-IFNAR1-FLAG or empty vector as indicated. 40 h later, cells were treated as indicated for 4 h. Western blots of cell lysates were probed with anti-FLAG (top panel) and anti-β-actin (bottom panel) antibodies, respectively