Peptide inhibitor of cytokinesis during sporulation in Bacillus subtilis.
Cytokinesis in bacteria is mediated by the tubulin-like protein FtsZ, which forms a Z-ring at the division site. Using FtsZ as bait in a two-hybrid screen, we discovered a 40-amino-acid peptide, termed MciZ, from Bacillus subtilis that appeared to interact with FtsZ. Cells engineered to produce MciZ during growth formed aseptate filaments that lacked Z-rings. A mutant resistant to the toxic effects of MciZ during growth harboured an amino acid substitution near the GTP binding pocket of FtsZ. Synthetic MciZ inhibited the GTPase activity of FtsZ and its ability to polymerize. MciZ was produced during sporulation under the control of the transcription factor sigma(E). In the absence of MciZ, the mother-cell compartment of the sporangium aberrantly formed a Z-ring at a time in development when cytokinetic events normally have ceased. We conclude that MciZ is a previously unrecognized inhibitor of FtsZ that prevents inappropriate Z-ring formation during sporulation. MciZ showed little sequence similarity to other peptides in the databases, except the mouse antimicrobial peptide CRAMP, which we speculate works in part by inhibiting cytokinesis.
Handler
Aaron A
AA
The Biological Laboratories, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
Lim
Joo Eun
JE
Losick
Richard
R
D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000378:metabolism; D001412:Bacillus subtilis / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054804:Cathelicidins; D048749:Cytokinesis / Q000187:drug effects*; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013171:Spores, Bacterial / Q000254:growth & development*; D020798:Two-Hybrid System Techniques
D023181:Antimicrobial Cationic Peptides; D001426:Bacterial Proteins; D054804:Cathelicidins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria