Figure 5.

Role of SUMOylation in the regulation of Tax oncoprotein of the human T-cell lymphotropic virus type I (HTLV1) virus. Upon As₂O₃ and INFα treatment, Tax is recruited to PML NBs. It is then poly-SUMOylated, recognized by RNF4, poly-ubiquitylated, and degraded by the proteasome. Another involvement of SUMOylation in the regulation of Tax was shown upon DNA damage, where its RNF4-dependant ubiquitylation triggers its cytosolic translocation. This leads to the activation of the NFκB pathway, probably thanks to its ability to bind to and activate NEMO and the IKK complex.