FIGURE 2.

Mapping of regions responsible for interaction between Arkadia and RB1CC1. A, shown is a schematic representation of RB1CC1 deletion mutants. The putative Arkadia-binding region is indicated by a bold arrow. a.a., amino acids. B, shown is mapping of the Arkadia binding region on RB1CC1. HEK293T cells were transfected with the deletion mutants of RB1CC1 and the Arkadia C937A mutant lacking E3 ligase activity (Arkadia-CA). RB1CC1 was immunoprecipitated, and co-precipitated Arkadia was detected. Expression of Arkadia and RB1CC1 mutants is shown in the two bottom panels. C, Arkadia fragments used for binding assay are schematically presented. Asterisks represent putative nuclear localization signals. A putative RB1CC1 binding region is indicated by a bold arrow. D, mapping of the RB1CC1 binding region on Arkadia is shown. HEK293T cells were transfected with RB1CC1 and various Arkadia fragments. Arkadia fragments were immunoprecipitated, and co-precipitated RB1CC1 was visualized. Expression of each protein is presented in the two bottom panels.