Diverse Gut Pathogens Exploit the Host Engulfment Pathway via a Conserved Mechanism

Area of Science:

• Cell biology
• Microbiology
• Immunology

Background:

• Macrophages engulf pathogens in phagolysosomes, but pathogens can escape by subverting host cells using effector proteins.
• These effectors often contain a WxxxE motif and help pathogens form protective vacuoles.

Approach:

• Identified a conserved hotspot on the PH-domain of ELMO1 (Engulfment and Cell Motility1) targeted by WxxxE-effectors.
• Utilized homology modeling and site-directed mutagenesis to confirm binding of a lysine triad on ELMO1 to effectors like SifA, IpgB1, IpgB2, and Map.
• Integrated protein-protein interaction networks and performed functional studies to assess the impact of disrupted SifA-ELMO1 interaction.

Key Points:

• A specific lysine triad on ELMO1 directly binds diverse WxxxE-motif containing effectors from various pathogens.
• Disrupting the SifA-ELMO1 interaction reduces Rac1 activity and microbial invasion.
• The conserved binding interface suggests a convergence point for pathogen intrusion and host vulnerability.

Conclusions:

• The ELMO1 binding site represents a critical interface in the co-evolutionary arms race between pathogens and host cells.
• Targeting this interface could be a therapeutic strategy to combat microbial infections.