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Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
Inside-out Z rings--constriction with and without GTP hydrolysis
Masaki Osawa1, Harold P Erickson
1Department of Cell Biology, 3079, Duke University Medical Center, Durham, NC 27710-3709, USA. m.osawa@cellbio.duke.edu
Molecular Microbiology
|June 3, 2011
Summary
Bacterial cell division protein FtsZ forms dynamic
Area of Science:
- Cell Biology
- Microbiology
- Biochemistry
Background:
- FtsZ, a homologue of eukaryotic tubulin, forms the Z ring essential for bacterial cytokinesis.
- Previous work demonstrated FtsZ with a C-terminal membrane-inserting helix (mts) can form contractile Z rings in liposomes.
Purpose of the Study:
- To investigate the assembly and constriction dynamics of 'inside-out' Z rings formed by mts-FtsZ-YFP.
- To determine the role of GTP hydrolysis in Z-ring constriction and force generation.
Main Methods:
- In vitro assembly of FtsZ variants in tubular liposomes.
- Utilizing microscopy to observe Z-ring formation and dynamics.
- Analyzing the effect of GTP hydrolysis inhibition on Z-ring constriction.
Main Results:
- mts-FtsZ-YFP assembled 'inside-out' Z rings on the exterior of tubular liposomes.
- These dynamic rings generated constriction forces, consistent with models of membrane bending by curved protofilaments.
- Inhibition of GTP hydrolysis allowed initial constriction but led to rapid stabilization, halting further constriction.
Conclusions:
- Remodelling of the Z ring, driven by GTP hydrolysis and subunit exchange, is crucial for sustained constriction during bacterial cytokinesis.
- The study provides insights into the physical mechanisms of Z-ring-mediated membrane constriction.
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