FibA and PilA act cooperatively during fruiting body formation of Myxococcus xanthus.
The extracellular matrix (ECM) of Myxococcus xanthus is essential for social (S-) motility and fruiting body formation. An ECM-bound protein, FibA, is homologous to M4 zinc metalloproteases and is important for stimulation by a phosphatidylethanolamine (PE) chemoattractant and for formation of discrete aggregation foci. In this work, we demonstrate that a correlation exists between a reduced ability to respond to PE and the observed defects in fruiting body morphogenesis. Furthermore, the fibA aggregation defect is accentuated by the absence of either PilA, the structural subunit of type IV pili, or DifD, a chemosensory response regulator. The inability to form fruiting bodies is not due to a loss of S-motility, but rather the loss of PilA and pili as pilT fibA mutants form fruiting bodies. The FibA active site residue E342 is important for fruiting body morphogenesis in the absence of PilA. Mutants exhibiting defects in fruiting body morphogenesis also produce fewer viable spores. It is proposed that FibA and PilA act as extracellular sensors for developmental signals.
Bonner
Pamela J
PJ
Department of Microbiology, University of Georgia, Athens, GA 30602, USA.
Black
Wesley P
WP
Yang
Zhaomin
Z
Shimkets
Lawrence J
LJ
D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D002633:Chemotaxis / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D008969:Molecular Sequence Data; D016941:Myxococcus xanthus / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D016415:Sequence Alignment
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D008565:Membrane Proteins; D010714:Phosphatidylethanolamines; C118696:fibA protein, bacteria; C483858:phosphatidylethanolamine