Functional redundancy between penicillin-binding proteins during asymmetric cell division in Clostridioides difficile

Area of Science:

• Microbiology
• Cell Biology
• Biochemistry

Background:

• Peptidoglycan synthesis is vital for bacterial growth and division, involving SEDS glycosyltransferases and class B penicillin-binding proteins (bPBPs).
• Multiple bPBPs in bacteria can have specialized or redundant roles, contributing to cell wall stress resistance and antibiotic resistance.
• Endospore-forming bacteria utilize multiple bPBPs for sporulation, a complex morphological process.

Purpose of the Study:

• To investigate the role of the sporulation-specific bPBP, SpoVD, in asymmetric division and spore cortex peptidoglycan synthesis during sporulation in Clostridioides difficile.
• To elucidate the mechanisms underlying functional redundancy among bPBPs, particularly in the context of sporulation and cell wall stress.

Main Methods:

• Genetic manipulation of Clostridioides difficile to study the function of SpoVD, SpoVE, and PBP3 during sporulation.
• Analysis of cell morphology and peptidoglycan synthesis during asymmetric division and cortex formation.
• Investigating protein-protein interactions between SpoVD, SpoVE, and PBP3 using co-immunoprecipitation or similar techniques.

Main Results:

• SpoVD's catalytic activity is essential for spore cortex peptidoglycan synthesis but dispensable for mediating asymmetric division in Clostridioides difficile.
• The dispensability of SpoVD's catalytic activity for asymmetric division requires its SEDS partner, SpoVE, and is facilitated by another sporulation-induced bPBP, PBP3.
• PBP3 interacts with SpoVD and potentially other components of the asymmetric division machinery.

Conclusions:

• SpoVD plays a dual role in Clostridioides difficile sporulation, with its catalytic activity being crucial for cortex synthesis but not asymmetric division.
• Functional redundancy among bPBPs, exemplified by SpoVD, SpoVE, and PBP3, provides a mechanism for coping with cell wall stresses and may contribute to antibiotic resistance.
• Understanding these compensatory mechanisms involving bPBPs can offer insights into bacterial survival strategies and potential therapeutic targets.