Working model for the removal of Rab5 from the LCV. (I–IV) GDP-bound inactive Rab5 is targeted to the LCV and activated by the exchange of GDP for GTP (I). The SCF complex containing Lpg2525 recognizes Rab5 on the LCV and catalyzes ubiquitination on it (II). RabGAP-5 associates with Rab5, which is ubiquitinated on its K134 residue (III). RabGAP-5 inactivates Rab5 and removes it from the LCV (IV).