Enteropathogenic E. coli (EPEC) transfers its receptor for intimate adherence into mammalian cells

Area of Science:

• Microbiology
• Cell Biology
• Pathogen-Host Interactions

Background:

• Enteropathogenic E. coli (EPEC) causes disease by rearranging host cell actin and forming pedestals.
• EPEC adherence relies on the interaction between bacterial intimin and a host cell receptor (Hp90).
• This interaction triggers host signaling and actin nucleation.

Purpose of the Study:

• To elucidate the true identity of the Hp90 protein involved in EPEC adherence.
• To understand the mechanism by which EPEC establishes intimate attachment and pedestal formation.

Main Methods:

• Investigated the molecular nature of the Hp90 protein.
• Analyzed the role of bacterial proteins in host cell manipulation.

Main Results:

• Hp90 is identified as a bacterial protein, termed Tir (Translocated Intimin Receptor).
• EPEC injects Tir into host cells, which then serves as the receptor for intimin.
• Tir is tyrosine-phosphorylated upon translocation into the host cell, mediating adherence and signaling.

Conclusions:

• EPEC utilizes a novel strategy by inserting its own receptor (Tir) into host cell membranes.
• This mechanism is crucial for intimate bacterial attachment, host cell actin rearrangement, and pedestal formation.
• Tir acts as a key virulence factor, hijacking host cell machinery for bacterial invasion.