Figure 4.

RPN1 was identified as the protein that binds to FUT8 in an SH3 domain–dependent manner. A, FUT8 WT and ΔSH3 expressed in HEK293 FUT8KO cells were immunoprecipitated (IP), and the precipitated proteins were subjected to silver staining. Arrows, co-immunoprecipitated proteins with FUT8 that were identified by proteomics. B, HEK293 FUT8KO cells were transfected with the plasmids for FUT8 WT and ΔSH3, lysed, and subjected to immunoprecipitation with anti-FUT8 (sheep Ab) antibodies. The immunoprecipitated proteins were analyzed by Western blotting with anti-FUT8 (sheep Ab), anti-RPN1, and anti-GAPDH Abs.