GpsB Coordinates Cell Division and Cell Surface Decoration by Wall Teichoic Acids in Staphylococcus aureus

Area of Science:

• Microbiology
• Cell Biology
• Biochemistry

Background:

• Bacterial cell division requires complex protein coordination, with regulation poorly understood in pathogens like Staphylococcus aureus.
• GpsB, a conserved protein in Firmicutes, is known to regulate cell division and cell wall synthesis in various species.
• Previous work showed GpsB directly regulates FtsZ polymerization in S. aureus.

Purpose of the Study:

• To investigate the function of GpsB in S. aureus, particularly its role in cell division and cell wall synthesis.
• To identify key residues and interaction partners of GpsB involved in its regulatory functions.
• To explore the potential conservation of GpsB's function in other bacterial species.

Main Methods:

• Isolation and characterization of spontaneous suppressors of S. aureus GpsB overproduction lethality in Bacillus subtilis.
• Identification of critical residues within GpsB essential for its function.
• Biochemical assays to demonstrate direct interaction between GpsB and the wall teichoic acid (WTA) export protein TarG in S. aureus.
• Localization studies of TarG in S. aureus to assess its association with the divisome complex.

Main Results:

• Several key residues essential for GpsB function were identified through suppressor analysis.
• GpsB directly interacts with TarG, a protein involved in WTA export, and a specific region of GpsB mediates this interaction.
• TarG localization suggests the WTA machinery is integrated into the divisome complex.

Conclusions:

• GpsB plays a crucial role in S. aureus by linking cell division and WTA biosynthesis, essential for cell surface decoration.
• The interaction between GpsB and TarG highlights a novel mechanism for coordinating cell envelope biogenesis.
• GpsB's dual role in cell division and WTA synthesis may be conserved among GpsB homologs, impacting bacterial cytokinesis and cell wall integrity.