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Rab6 regulates recycling and retrograde trafficking of MR1 molecules

Megan E Huber1,2, Regina Kurapova1, Chelsea M Heisler1

  • 1Department of Pulmonary and Critical Care Medicine, Oregon Health & Science University, Portland, OR, 97239, USA.

Scientific Reports
|November 28, 2020
PubMed

Insights

Mucosal-associated invariant T (MAIT) cells use the MR1 molecule to detect bacterial metabolites. Rab6 protein controls MR1 recycling, influencing how MAIT cells recognize infected lung cells.

Area of Science:

  • Immunology
  • Cell Biology
  • Microbiology

Background:

  • Mucosal-associated invariant T (MAIT) cells are crucial for early immune responses against lung pathogens.
  • MAIT cells identify bacterial metabolites presented by the MR1 molecule.
  • MR1 ligand sampling involves intracellular pathways, potentially including endosomal trafficking.

Purpose of the Study:

  • To investigate the role of Rab6, a small GTPase, in MR1 trafficking and antigen presentation.
  • To understand how Rab6 influences the presentation of Mycobacterium tuberculosis (Mtb) ligands to MAIT cells.

Main Methods:

  • Utilized inducible MR1 expression systems.
  • Investigated Rab6-mediated endosomal trafficking pathways.
  • Examined MR1 recycling from the cell surface to the trans-Golgi network (TGN).

Main Results:

  • Rab6 was found to regulate the recycling of MR1 molecules.
  • MR1 recycles via endosomal compartments to the TGN, dependent on Rab6.
  • This Rab6-dependent pathway makes MR1 available for reloading with bacterial ligands.

Conclusions:

  • Rab6 controls a key pathway for MR1 recycling and ligand exchange.
  • This mechanism is vital for MAIT cell recognition of Mtb-infected cells in the lung.
  • Understanding MR1 trafficking enhances insights into innate-like T cell responses.

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