The Escherichia coli Hsp90 homolog plays a role during bacterial cell division

Wednesday, September 24, 2014 — Poster Session IV
10:00 a.m. –12:00 p.m.	FAES Academic Center	NCI	MICROBIO-7

* FARE Award Winner

Authors

• M. Markovski
• S. Wickner

Abstract

Conserved from bacteria to humans, heat shock proteins (Hsps) are ubiquitous molecular chaperones that assist in protein folding during stress conditions. In particular, the members of the Hsp90 chaperone family are ATP-dependent molecular machines that refold non-native or unfolded proteins into their native conformations. In eukaryotes, Hsp90 is an essential protein and is required to remodel and activate hundreds of clients. During tumor progression, cancer cells exploit Hsp90 because it is needed for the function of tumor-promoting factors. In Escherichia coli, the activity of its Hsp90 homolog (Hsp90Ec) has remained elusive. Little is known about its function. Here, we investigate the role that Hsp90Ec plays in bacterial cells. Recently, our group showed that overexpression of Hsp90Ec causes cells to filament. To determine whether inhibition of the essential complex required for cell division and constriction causes this phenotype, we visualized early divisome formation using fluorescence microscopy in cells overexpressing Hsp90Ec and looked for an interaction between Hsp90Ec and the first divisome component FtsZ using an in vitro co-sedimentation assay. Our results suggest that under stress, high levels of Hsp90Ec may play a role in the early stages of cell division possibly by preventing divisome assembly at improper locations by sequestering FtsZ.

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