Figure 2.

SUMOylation of ScPCNA catalyzed by the Arabidopsis SUMOylation cascade. ScPCNA labeled with a Myc tag was isolated from E. coli and directly applied to the gel (lane 1), or incubated with AtSUMO1 in the presences of Arabidopsis SUMO E1 and E2 enzymes (lane 2). In lanes 3 to 5, selected components of the Arabidopsis SUMOylation machinery, as listed in the top part of the figure, were excluded from the reaction mixture. Proteins were separated on a 12% SDS-polyacrylamide gel, and ScPCNA mobility shifts were detected by western-blot analysis using a Myc peptide-specific antiserum.