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Updated: Mar 19, 2026
11:50
Purification and Quality Control of Recombinant Septin Complexes for Cell-Free Reconstitution
Published on: June 23, 2022
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Septins guide microtubule protrusions induced by actin-depolymerizing toxins like Clostridium difficile transferase
Thilo Nölke1, Carsten Schwan1, Friederike Lehmann2
1Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany;
Summary
Septins are crucial for Clostridium difficile transferase (CDT)-induced cell protrusions, which enhance pathogen adherence. This study reveals how CDT hijacks septins and microtubule interactions for cellular manipulation.
Area of Science:
- Cell Biology
- Microbiology
- Molecular Biology
Background:
- Hypervirulent Clostridium difficile strains cause significant morbidity and mortality.
- Clostridium difficile transferase (CDT) is an actin-ADP ribosylating toxin produced by these strains.
- CDT induces cell protrusions, actin depolymerization, and increases pathogen adherence.
Purpose of the Study:
- To investigate the role of septins in CDT-induced protrusion formation.
- To elucidate the molecular mechanisms by which CDT manipulates host cell structures.
Main Methods:
- Septin localization studies at protrusion sites.
- Inhibition of septin function using forchlorfenuron or knockdown.
- Co-immunoprecipitation and surface plasmon resonance to study protein interactions.
- Colocalization studies with Cdc42, Borgs, and EB1.
Main Results:
- Septins (SEPT2, -6, -7, -9) accumulate at protrusion sites, forming collar-like structures.
- Septin inhibition or knockdown prevents CDT-induced protrusion formation.
- Septins colocalize with Cdc42 and Borgs, upstream regulators of septin polymerization.
- Septins bind with high affinity to EB1, influencing microtubule dynamics.
Conclusions:
- Septins are essential for CDT-induced cell protrusions.
- CDT exploits conserved mechanisms of microtubule-membrane interactions involving septins, Cdc42, Borgs, and actin remodeling.
- Understanding these interactions could inform strategies against C. difficile infections.
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