Stimulation of DNA Glycosylase Activities by XPC Protein Complex: Roles of Protein-Protein Interactions

Figure 3

XPC physically interacts with SUMO-1-conjugated TDG, but not with EcMUG. Glutathione-Sepharose beads (20 𝜇l) were incubated in 100 𝜇l of the binding mixture containing 10 nM of GST (negative control), GST-TDG (positive control), GST-EcMUG, or SUMO-1-GST-TDG in the presence of the same concentration of XPC-RAD23B. After extensive washing, bound proteins were eluted with buffer containing 10 mM glutathione. One-fourth of each eluate was mixed with whole cell extract from XP4PASV cells which do not express XPC and subjected to 8% SDS-PAGE followed by immunoblotting with anti-XPC antibody (upper panel). The same samples were also subjected to 12% SDS-PAGE followed by immunoblotting with anti-GST antibody (lower panel).