EspH utilizes phosphoinositide and Rab binding domains to interact with plasma membrane infection sites and Rab...

Area of Science:

• Microbiology
• Cell Biology
• Molecular Biology

Background:

• Enteropathogenic E. coli (EPEC) is a significant cause of persistent diarrhea.
• EPEC injects effector proteins into host cells to manipulate cellular functions.
• Understanding effector mechanisms is key to combating EPEC infections.

Purpose of the Study:

• To elucidate the host-pathogen interactions mediated by the EPEC effector protein EspH.
• To identify the specific host factors and domains within EspH involved in virulence.

Main Methods:

• Utilized AlphaFold for structural predictions.
• Employed site-directed mutagenesis to probe EspH function.
• Performed gene knockout experiments for Rab8a.
• Investigated protein-protein interactions and cellular localization.

Main Results:

• EspH interacts with multiple host Rab GTPases, with specific residues (Glu37, Lys41) critical for binding.
• Mutations in these residues abrogate EspH's ability to inhibit Akt/mTORC1 signaling, lysosomal exocytosis, and bacterial invasion.
• Rab8a plays a role in Akt/mTORC1 signaling and lysosomal exocytosis.
• A phosphoinositide-binding domain in EspH, including a critical tyrosine, is essential for Rab interaction and localization at infection sites.

Conclusions:

• Identified novel EspH-Rab GTPase interactions crucial for EPEC pathogenesis.
• Demonstrated the role of specific EspH residues and a phosphoinositide-binding domain in virulence.
• Revealed EspH-dependent mechanisms influencing host immune signaling and membrane trafficking during EPEC infection.