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Adenine Nucleotide-Dependent Regulation of Assembly of Bacterial Tubulin-Like FtsZ by a Hypermorph of Bacterial Actin-Like FtsA

Publication Date

5-22-2009

Journal

The Journal of Biological Chemistry

Abstract

Cytokinesis in bacteria depends upon the contractile Z ring, which is composed of dynamic polymers of the tubulin homolog FtsZ as well as other membrane-associated proteins such as FtsA, a homolog of actin that is required for membrane attachment of the Z ring and its subsequent constriction. Here we show that a previously characterized hypermorphic mutant FtsA (FtsA*) partially disassembled FtsZ polymers in vitro. This effect was strictly dependent on ATP or ADP binding to FtsA* and occurred at substoichiometric levels relative to FtsZ, similar to cellular levels. Nucleotide-bound FtsA* did not affect FtsZ GTPase activity or the critical concentration for FtsZ assembly but was able to disassemble preformed FtsZ polymers, suggesting that FtsA* acts on FtsZ polymers. Microscopic examination of the inhibited FtsZ polymers revealed a transition from long, straight polymers and polymer bundles to mainly short, curved protofilaments. These results indicate that a bacterial actin, when activated by adenine nucleotides, can modify the length distribution of bacterial tubulin polymers, analogous to the effects of actin-depolymerizing factor/cofilin on F-actin.

Keywords

Actins, Adenine Nucleotides, Adenosine Diphosphate, Adenosine Triphosphate, Adenylyl Imidodiphosphate, Bacterial Proteins, Cytoskeletal Proteins, Escherichia coli, Escherichia coli Proteins, GTP Phosphohydrolases, Histidine, Hydrogen-Ion Concentration, Oligopeptides, Polymers, Protein Binding, Tubulin

DOI

10.1074/jbc.M808872200

PMID

19297332

PMCID

PMC2682856

PubMedCentral® Posted Date

May 2009

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

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