Rab11 is one of best-studied Rab GTPases; it associates primarily with recycling endosomes (REs), which are often found in a perinuclear region, and regulates the recycling of endocytosed proteins. However, it remains poorly understood which step in the recycling process Rab11 is involved in. On page , Kazuhisa Nakayama and colleagues aim to shed light on this question by closely analysing the Rab11 distribution in the cell. They find that some of the Rab11, together with the recycling protein transferring receptor (TfnR), also localises to the peripheral tip regions of the cell. Importantly, the authors show that Rab11 acts with the exocyst complex in the docking and fusion of REs at the plasma membrane (PM), as depletion of Rab11, or of exocyst components, abolishes the fusion of the vesicles with the PM and leads to their accumulation beneath it. On the basis of these observations, the authors propose that Rab11 participates in one of the final steps in exocytosis, the exit of recycling vesicles from perinuclear REs, which are transported along microtubules towards the cell periphery without any involvement of Rab11, by regulating the tethering of recycling vesicles to the PM in concert with the exocyst complex. Further experiments will help to elucidate how exactly Rab11 mediates the fusion of REs before their exocytosis and the other factors involved.
