Cardiolipin-Containing Lipid Membranes Attract the Bacterial Cell Division Protein DivIVA

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• DivIVA protein is a key spatial regulator of bacterial cell division in Gram-positive bacteria.
• It localizes to curved membrane regions, such as cell poles and division sites, recruiting binding partners.
• Previous hypotheses suggested negative membrane curvature sensing as DivIVA's primary binding mechanism.

Purpose of the Study:

• To investigate the binding mechanism of DivIVA from Clostridioides difficile.
• To determine if DivIVA interacts with specific membrane phospholipids.
• To explore DivIVA's role in modifying lipid bilayers during cell division.

Main Methods:

• Lipid-binding assays using Clostridioides difficile DivIVA.
• Analysis of DivIVA's interaction with various phospholipids, focusing on cardiolipin.
• Microscopy and biophysical techniques to observe DivIVA-induced changes in lipid bilayers.

Main Results:

• Clostridioides difficile DivIVA preferentially binds to membranes containing negatively charged phospholipids, particularly cardiolipin.
• DivIVA binding alters lipid distribution within the membrane.
• DivIVA induces significant changes in the structure of cardiolipin-containing lipid bilayers.

Conclusions:

• DivIVA's interaction with bacterial membranes is mediated by specific negatively charged phospholipids, not solely by membrane curvature.
• DivIVA actively modifies lipid bilayers upon binding.
• These findings suggest a more complex and previously unrecognized active role for DivIVA in the formation of the cell division septal membrane.