Figure 7: Model for the role of ubiquitination in BRI1 endocytosis.

Ubiquitination of BRI1 acts at the cell surface, redundantly with other mechanisms, to mediate BRI1 internalization. Internalized BRI1 may be deubiquitinated and recycled to the plasma membrane, or sorted into late endosomal compartments for vacuolar delivery. Ubiquitination of BRI1 is essential for proper sorting and targeting to the vacuole.