RabGAP1L modulates Rab7A and Rab10 to orchestrate cell-autonomous immunity

Area of Science:

• Cell biology
• Immunology
• Microbiology

Background:

• Cell-autonomous immunity employs membrane trafficking, including selective autophagy and extracellular expulsion, to combat intracellular pathogens.
• The regulatory mechanisms coordinating these distinct cell-autonomous defense systems remain largely uncharacterized.

Purpose of the Study:

• To investigate the role of Rab GTPase-activating protein 1-like (RabGAP1L) in modulating cell-autonomous immune responses against group A Streptococcus (GAS).
• To elucidate the specific Rab GTPases and cellular pathways regulated by RabGAP1L during infection.

Main Methods:

• Confocal microscopy was used to analyze the localization and function of Rab GTPases and trafficking pathways.
• Genetic manipulation, including ATG7 and ATG5 knockout models, was employed to assess the impact of autophagy deficiency.
• Infection models with group A Streptococcus (GAS) were utilized to study host-pathogen interactions.

Main Results:

• RabGAP1L inactivates Rab7A and Rab10, key regulators of cellular defense mechanisms.
• Rab7A promotes selective autophagy against GAS by facilitating endolysosomal trafficking.
• Rab7A and Rab10 inhibit GAS expulsion by interfering with Rab11A-positive recycling endosome formation, while autophagy-deficient cells show increased RabGAP1L-dependent bacterial expulsion.

Conclusions:

• RabGAP1L acts as a crucial regulator of cell-autonomous immunity by coordinating distinct pathways involving Rab GTPases.
• The findings reveal a novel mechanism where RabGAP1L balances selective autophagy and bacterial expulsion to enhance intracellular pathogen clearance.