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Analysis of MinC reveals two independent domains involved in interaction with MinD and FtsZ
1Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City 66160, USA.
Abstract:
In Escherichia coli FtsZ assembles into a Z ring at midcell while assembly at polar sites is prevented by the min system. MinC, a component of this system, is an inhibitor of FtsZ assembly that is positioned within the cell by interaction with MinDE. In this study we found that MinC consists of two functional domains connected by a short linker. When fused to MalE the N-terminal domain is able to inhibit cell division and prevent FtsZ assembly in vitro. The C-terminal domain interacts with MinD, and expression in wild-type cells as a MalE fusion disrupts min function, resulting in a minicell phenotype. We also find that MinC is an oligomer, probably a dimer. Although the C-terminal domain is clearly sufficient for oligomerization, the N-terminal domain also promotes oligomerization. These results demonstrate that MinC consists of two independently functioning domains: an N-terminal domain capable of inhibiting FtsZ assembly and a C-terminal domain responsible for localization of MinC through interaction with MinD. The fusion of these two independent domains is required to achieve topological regulation of Z ring assembly.
Insights
MinC, a cell division inhibitor, has two domains: one blocks FtsZ assembly, the other localizes MinC. Their fusion regulates Z-ring assembly, preventing polar division in Escherichia coli.
Area of Science:
- Cell biology
- Microbiology
- Molecular biology
Background:
- Escherichia coli cell division involves FtsZ ring assembly at midcell.
- The Min system prevents FtsZ assembly at polar sites.
- MinC inhibits FtsZ assembly and is localized by MinDE.
Purpose of the Study:
- To elucidate the functional domains of MinC.
- To understand the mechanism of MinC's localization and inhibition.
- To investigate the role of MinC oligomerization in cell division regulation.
Main Methods:
- Domain analysis of MinC through fusions with MalE.
- In vitro FtsZ assembly inhibition assays.
- Expression of MinC fusions in wild-type Escherichia coli.
Main Results:
- MinC comprises two functional domains: N-terminal (inhibits FtsZ assembly) and C-terminal (interacts with MinD).
- MalE-N-terminal MinC fusion inhibits cell division and FtsZ assembly.
- MalE-C-terminal MinC fusion disrupts Min system function, causing a minicell phenotype.
- MinC exhibits oligomerization, likely dimeric, with both domains contributing.
Conclusions:
- MinC has two independent domains: one for FtsZ inhibition and one for MinD-mediated localization.
- The combined action of these domains is essential for topological regulation of Z-ring assembly.
- Understanding these domains provides insight into bacterial cell division control.