The Che4 pathway of Myxococcus xanthus regulates type IV pilus-mediated motility.
Myxococcus xanthus co-ordinates cell movement during its complex life cycle using multiple chemotaxis-like signal transduction pathways. These pathways regulate both type IV pilus-mediated social (S) motility and adventurous (A) motility. During a search for new chemoreceptors, we identified the che4 operon, which encodes homologues to a MCP (methyl-accepting chemotaxis protein), two CheWs, a hybrid CheA-CheY, a response regulator and a CheR. Deletion of the che4 operon did not cause swarming or developmental defects in either the wild-type (A(+)S(+)) strain or in a strain sustaining only A motility (A(+)S(-)). However, in a strain displaying only S motility (A(-)S(+)), deletion of the che4 operon or the gene encoding the response regulator, cheY4, caused enhanced vegetative swarming and prevented aggregation and sporulation. In contrast, deletion of mcp4 caused reduced vegetative swarming and enhanced development compared with the parent strain. Single-cell analysis of the motility of the A(-)S(+) parent strain revealed a previously unknown inverse correlation between velocity and reversal frequency. Thus, cells that moved at higher velocities showed a reduced reversal frequency. This co-ordination of reversal frequency and velocity was lost in the mcp4 and cheY4 mutants. The structural components of the S motility apparatus were unaffected in the che4 mutants, suggesting that the Che4 system affects reversal frequency of cells by modulating the function of the type IV pilus.
Vlamakis
Hera C
HC
Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3204, USA.
Kirby
John R
JR
Zusman
David R
DR
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D010861:Fimbriae, Bacterial / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order; D005798:Genes, Bacterial; D017930:Genes, Reporter; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D000072236:Methyl-Accepting Chemotaxis Proteins; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009068:Movement; D016941:Myxococcus xanthus / Q000235:genetics / Q000502:physiology*; D009876:Operon; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C051236:CheW protein, Bacteria; D008780:Methyltransferases; C038706:chemotaxis methyltransferase; D001616:beta-Galactosidase