DepartmentMolecular Cell Biology
Publication date9-Mar-2010

Shinya Sugimoto, Kunitoshi Yamanaka, Shingo Nishikori, Atsushi Miyagi, Toshio Ando, Teru Ogura. (2010) AAA+ chaperone ClpX regulates dynamics of prokaryotic cytoskeletal protein FtsZ. J. Biol. Chem. 285: 6648-6657.

  AAA+ chaperone ClpX has been suggested to be a modulator of prokaryotic cytoskeletal protein FtsZ, but the details of recognition and remodeling of FtsZ by ClpX are largely unknown. In this study, we have extensively investigated the nature of FtsZ polymers and mechanisms of ClpX-regulated FtsZ polymer dynamics. We found that FtsZ polymerization is inhibited by ClpX in an ATP-independent manner and that the N-terminal domain of ClpX plays a crucial role for the inhibition of FtsZ polymerization. Single molecule analysis with high speed atomic force microscopy directly revealed that FtsZ polymer is in a dynamic equilibrium between polymerization and depolymerization on a time scale of several seconds. ClpX disassembles FtsZ polymers presumably by blocking reassembly of FtsZ. Furthermore, Escherichia coli cells overproducing ClpX and N-terminal domain of ClpX show filamentous morphology with abnormal localization of FtsZ. These data together suggest that ClpX modulates FtsZ polymer dynamics in an ATP-independent fashion, which is achieved by interaction between the N-terminal domain of ClpX and FtsZ monomers or oligomers.



Fig : High speed AFM images of FtsZ polymers.

A) Raw AFM images of FtsZ polymers taken at the indicated times. There are many single filaments, bundles, and curved filaments.

B) To emphasize dynamic nature of filaments, raw images in (A) are shown in gray scale and selected filaments are colored in red and yellow. A straight filament was curved, disassembled, reassembled, and bundled during the observation period. A scale bar is given as 100 nm.

C) The model for conformational changes of FtsZ polymers. FtsZ is in a GTP-dependent polymer dynamics. GTP-binding triggers FtsZ polymerization, while hydrolysis or release of GTP induces depolymerization. Reassembly of the disassembled FtsZ filaments and/or monomers is induced by GDP/GTP exchange or GTP rebinding. Some straight filaments gradually curved, and others laterally associated into bundles.