Human Papillomavirus (HPV) Upregulates the Cellular Deubiquitinase UCHL1 to Suppress the Keratinocyte's Innate Immune Response
Figure 8
Interaction of UCHL1 with the PRR downstream signaling molecules TRAF6 and NEMO.
(A) UCHL1 overexpression results in a modest poly-ubiquitination of TRAF6. HEK293T cells were co-transfected with Flag-TRAF6, HA-tagged WT-Ub, and with either empty vector or WT UCHL1. TRAF6 was immunoprecipitated with Flag antibody and western Blotting (WB) was done with HA or Flag antibodies (top two panels). The bottom three panels show a WB analysis of UCHL1 and Flag of non-immunoprecipitated lysate and a Ponceau S stained loading control for WB. (B) The effect of UCHL1 on NEMO. HEK293T cells were co-transfected with Flag-NEMO, HA-tagged WT-Ub, and with either empty vector or WT UCHL1. NEMO was immunoprecipitated with Flag antibody and WB was done with HA or Flag antibodies (top two panels). (C) The overexpression of UCHL1 mediates the degradation of NEMO. HEK293T cells were co-transfected with Flag-NEMO, HA-tagged WT-Ub, and with either empty vector or WT UCHL1. Cells were left untreated or were treated with MG132, NEMO was immunoprecipitated with Flag antibody and WB was done with HA or Flag antibodies (top two panels). (D) USP8 does not deubiquitinate NEMO. HEK293T cells were co-transfected with Flag-NEMO, HA-tagged wild-type ubiquitin (WT-Ub) and UCHL1 or USP8. NEMO was immunoprecipitated with Flag antibody and WB was done with HA antibodies (top panel). The bottom four panels show a WB analysis of Flag, UCHL1, and USP8 of non-immunoprecipitated lysate and a Ponceau S stained loading control for WB.