Activating mutations of N-WASP alter Shigella pathogenesis

Area of Science:

• Microbiology
• Cell Biology
• Molecular Biology

Background:

• Shigella pathogenesis involves host protein N-WASP.
• N-WASP's structural conformation and phospho-regulation are key to Shigella infection.
• Understanding N-WASP's role is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the impact of N-WASP structural conformation and phospho-regulation on Shigella pathogenesis.
• To elucidate how N-WASP's open conformation and phosphorylation affect Shigella's lifecycle.

Main Methods:

• Constructed mutant N-WASP proteins with altered conformations (L229P, L232P) and phosphorylation states (Y253E, Y253F).
• Utilized pyrene actin assays to assess N-WASP activity.
• Infected cell lines expressing mutant N-WASP with Shigella to analyze actin tail formation, invasion, motility, and plaque formation.

Main Results:

• N-WASP L229P and L232P mutants showed constitutive activity in vitro.
• Cells expressing these mutants had shorter Shigella actin tails despite increased actin polymerization.
• N-WASP's structural conformation, not phosphorylation, significantly impacted Shigella plaque numbers.

Conclusions:

• N-WASP structural conformation is a critical regulator of Shigella pathogenesis.
• Specific N-WASP conformations influence distinct stages of the Shigella lifecycle.
• Targeting N-WASP conformation could offer novel therapeutic strategies against Shigella infections.