“…Both budding and fusion of the carriers depend on complex molecular machineries that are recruited from the cytosol onto membranes. A core component of the endosomal budding machinery is the retromer complex, which comprises a VPS26-VPS29-VPS35 heterotrimer and various combinations of sorting nexin (SNX) proteins, including a SNX1/2-SNX5/6 heterodimer, SNX3, and/or SNX27 ( Gallon and Cullen, 2015 ; Hierro et al ., 2015 ). Various other components, such as membrane phosphatidylinositol 3-phosphate (PtdIns3P; Burda et al ., 2002 ), the small GTPase Rab7 ( Rojas et al ., 2008 ; Seaman et al ., 2009 ), the Rab-GAP TBC1D5 ( Seaman et al ., 2009 ), the WASH complex ( Gomez and Billadeau, 2009 ), and dynactin ( Hong et al ., 2009 ; Wassmer et al ., 2009 ), interact with retromer to mediate different steps in the process of tubule formation and translocation.…”