Affinity purification of Ypt6 effectors and identification of TMF/ARA160 as a Rab6 interactor.

Rab/Ypt GTPases are key regulators of intracellular traffic in eukaryotic cells. One important function of Rab/Ypts is the nucleotide-dependent recruitment of downstream effector molecules onto the membrane of organelles. In budding yeast Ypt6 is required for recycling of membrane proteins from endosomes back to the Golgi. A biochemical approach based on the affinity purification of Ypt6:GTP-interacting proteins from yeast cytosol led to the identification of two conserved Ypt6 effectors, the tetrameric VFT complex and Sgm1. The mammalian homolog of Sgm1, TMF/ARA160, contains a short conserved coiled-coil motif that is sufficient for the binding to the three mammalian orthologs of Ypt6, Rab6A, Rab6A', and Rab6B.