Grab serves as a guanine exchange factor for the activation of Rab8. Grab also interacts with Tfrc and Rab11. Activated Rab8 is postulated to bind to the Sec15 subunit of the exocyst complex and thus recruits the exocyst complex to the recycling endosome. Another subunit of the exocyst complex interacts with the plasma membrane and is involved in the assembly of the fusion machinery. Fusion of the recycling endosome with the plasma membrane promotes exocytosis of Tf and completes the recycling Tfrc to the plasma membrane. Professional illustration by Somersault18:24.