Cell and Molecular Biology
Escherichia coli; ZapE; cell division
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During bacterial cell division, a large, dynamic cytoskeletal structure called the Z-ring assembles at the site of division. The Z-ring is comprised of the major cell division protein FtsZ, a tubulin-like GTPase that utilizes GTP to assemble into linear polymers. In Escherichia coli, there are several cell division proteins that interact with FtsZ and regulate Z-ring assembly, constriction, and disassembly. The accessory proteins that interact with FtsZ are called Z-ring associated proteins (ZAPs). The Zaps which include ZapA, ZapB, ZapC, ZapD and ZapE are recruited to the divisome and influence Z-ring assembly and stability. Specifically, ZapE was identified to be an ATPase present in Gram-negative bacteria including E. coli and accumulates during late constriction of the Z-ring. ZapE is important for bacterial growth under high temperatures and low- oxygen conditions. (Marteyn, et al., 2014, mBio). In vitro, ZapE destabilizes FtsZ polymers suggesting that it may promote Z-ring disassembly in vivo. To analyze ZapE function in vivo, we compared viability of strains deleted for zapE and minC under stressful conditions of high temperature, low salt, and anaerobiosis. MinC is an essential cell division protein involved in regulating assembly of the Z-ring. This assay will be used in future studies to identify mutations in zapE that lead to loss of function in vivo. To further evaluate ZapE function, we also amplified zapE for cloning into a high-copy inducible expression vector and attached a N-terminal histidine tag for subsequent purification by metal affinity chromatography. ZapE will be purified and examined for ATP hydrolysis and disassembly of FtsZ polymers in vitro. These studies will help us to further understand the functional role and biochemical activity of ZapE during cell division.