Pairing of selected E2s with different types of E3s.
A–F, SLCA of PUB20 composed of U-box (yellow) and ARM repeats (A), PUB24 composed of U-box (yellow) and ARM repeats (B), PUB4 composed of UND domain, U-box (yellow) and ARM repeats (C), PUB13 composed of UND domain, U-box (yellow) and ARM repeats (D), MIEL1 composed of two zinc fingers and a RING domain (red) (E), and AvrPtoB composed of two kinase-interacting domains and a U-box-like domain (purple) (F). E3s were assayed against UBC1 (group III), UBC5 (group IV), UBC9 (group VI), UBC12 (group VI), UBC17 (group VII), UBC26 (group XI), UBC28 (group VI), UBC30 (group VI), UBC35 (group XV), and COP10 transiently co-transformed in Arabidopsis mesophyll protoplasts. Transformation efficiencies were normalized by Renilla Luc harbored in the E2-containing vector. Strongest signal intensities are shown in blue. Values indicate the average of three independent biological experiments ± S.D. Statistically significant differences indicated by different letters were determined by one-way ANOVA and Tukey post hoc test (p < 0.05).