Diverted recycling-Shigella subversion of Rabs

Area of Science:

• Cell Biology
• Microbiology
• Pathogen-Host Interactions

Background:

• Small GTPases of the Rab protein family are crucial for intracellular vesicular trafficking.
• Intracellular bacteria commonly exploit host vesicular pathways for niche formation and survival.
• Rab subversion is well-documented for bacteria within vacuoles, but less so for those escaping into the cytoplasm.

Purpose of the Study:

• To review Rab targeting strategies employed by intracellular bacteria.
• To focus on Shigella's mechanism of Rab subversion for cytosolic escape.
• To introduce the concept of diverted recycling via host Rab GTPases as a novel pathogen strategy.

Main Methods:

• Review of recent literature on Rab subversion by intracellular bacteria.
• Focus on molecular mechanisms employed by Shigella, including effector proteins.
• Analysis of host-pathogen interactions at the level of vesicular trafficking.

Main Results:

• Shigella recruits Rab11, a key regulator of the recycling compartment, to macropinosomes using its effector IpgD.
• This recruitment facilitates efficient bacterial-containing vacuole (BCV) rupture and subsequent escape into the host cytoplasm.
• Examples of Rab targeting by both vacuole-dwelling and cytosolic bacteria are presented.

Conclusions:

• Host Rab GTPases are critical targets for intracellular bacterial pathogens.
• Shigella's strategy involves hijacking Rab11 for BCV rupture and cytosolic invasion.
• Diverted recycling through host Rab GTPases represents an emerging and significant pathogen survival mechanism.