Rabaptin-5 is an effector for the small GTPase Rab5, a regulator of the early steps in endocytosis. In addition, Rabaptin-5 interacts with the small GTPase Rab4 that has been implicated in recycling from early endosomes to the cell surface. Recently we have identified a ubiquitous transcript encoding the Rabaptin-5 isoform, Rabaptin-5d. To evaluate the interaction properties of Rabaptin-5d with the small GTPases Rab4 and Rab5, we have applied protein interaction assays using the yeast two-hybrid system and a glutathione S-transferase pull-down assay. .
