Schematic summary of WDR91 function in retromer-dependent recycling. SNX-retromer–mediated endosomal recycling occurs concomitantly with endosome conversion in the endosome–lysosome pathway. During the early-to-late endosome conversion, the active Rab7 recruits WDR91 to endosomes, where WDR91 inhibits endosomal PtdIns3P synthesis to facilitate endosome maturation. WDR91 promotes the interaction of Rab7 with SNX-retromer components, and interacts with the WASH complex on endosomes, thereby establishing the endosomal retrieval domain required for generation and release of retromer tubules.