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

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Rab small GTPases, including Rab11, are linked to endosome recycling and have been observed in mitotic spindles.
• Their precise physiological role in mammalian mitosis and tissue homeostasis remains unclear.

Purpose of the Study:

• To investigate the function of Rab11a and Rab11b in intestinal epithelial renewal using genetically engineered mouse models.
• To elucidate the molecular mechanisms by which Rab11 isoforms regulate cell division.

Main Methods:

• Generation of single and compound knockout mouse models for Rab11a and Rab11b.
• Ex vivo analysis of enteroids derived from knockout mice.
• Proteomic profiling of Rab11a and Rab11b immunoprecipitates.
• Assessment of mitotic spindle formation and cell cycle progression.

Main Results:

• Compound ablation of Rab11a and Rab11b leads to severe intestinal defects, including defective cell cycle entry, mitotic arrest, apoptosis, and lethality within 3 days.
• Ex vivo enteroids lacking Rab11 exhibit abnormal spindle formation and cell death.
• Proteomic analysis identified shared interactors involved in mitotic spindle regulation, including KIF11.
• Rab11 disruption impairs KIF11 function, leading to abnormal spindle assembly and cell division.

Conclusions:

• Rab11a and Rab11b play redundant roles in controlling mitotic spindle function and intestinal progenitor cell division.
• This Rab11-mediated mechanism is crucial for maintaining intestinal homeostasis and renewal.
• The findings suggest a conserved role for Rab11 in tissue renewal across mammalian systems.