RAB11A and RAB11B control mitotic spindle function in intestinal epithelial progenitor cells of mice

RAB11 small GTPases and associated recycling endosomes localize to mitotic spindles and have been implicated in the regulation of mitosis. However, the physiological significance of this function has not been addressed in mammals. We use newly engineered mouse models to investigate intestinal epithelial renewal in the absence of one or both of RAB11 family members, i.e. Rab11a and Rab11b. In contrast to single-knockout mice, the double-knockout animals demonstrate defects in cell cycle entry and significant mitotic arrest followed by apoptosis, and lethality within 3 days of gene ablation. Upon Rab11 deletion ex vivo, enteroids show abnormal mitotic spindle formation and cell death. Untargeted proteomic profiling of Rab11a and Rab11b immunoprecipitates reveals a shared interactome that includes mitotic spindle microtubule regulators. Disruption of Rab11 alters kinesin motor KIF11 function and impairs bipolar spindle formation and cell division. These data demonstrate that RAB11A and RAB11B redundantly control mitotic spindle function and intestinal progenitor cell division, a mechanism that may also be utilized to control homeostasis and renewal of other mammalian tissues.