Adenine nucleotide-dependent regulation of assembly of bacterial tubulin-like FtsZ by a hypermorph of bacterial actin-like FtsA.
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.
Beuria
Tushar K
TK
Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, Texas 77030, USA.
Mullapudi
Srinivas
S
Mileykovskaya
Eugenia
E
Sadasivam
Mahalakshmi
M
Dowhan
William
W
Margolin
William
W
D000199:Actins / Q000378:metabolism*; D000227:Adenine Nucleotides / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000266:Adenylyl Imidodiphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism* / Q000648:ultrastructure; D003598:Cytoskeletal Proteins / Q000378:metabolism* / Q000648:ultrastructure; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000302:isolation & purification / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006639:Histidine / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009842:Oligopeptides / Q000378:metabolism; D011108:Polymers / Q000378:metabolism; D011485:Protein Binding; D014404:Tubulin / Q000378:metabolism*
D000199:Actins; D000227:Adenine Nucleotides; D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C489310:FtsA protein, E coli; C071525:FtsZ protein, Bacteria; C471213:His-His-His-His-His-His; D009842:Oligopeptides; D011108:Polymers; D014404:Tubulin; D000266:Adenylyl Imidodiphosphate; D006639:Histidine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D020558:GTP Phosphohydrolases