Regulation of dynamic polarity switching in bacteria by a Ras-like G-protein and its cognate GAP.
The rod-shaped cells of the bacterium Myxococcus xanthus move uni-directionally and occasionally undergo reversals during which the leading/lagging polarity axis is inverted. Cellular reversals depend on pole-to-pole relocation of motility proteins that localize to the cell poles between reversals. We show that MglA is a Ras-like G-protein and acts as a nucleotide-dependent molecular switch to regulate motility and that MglB represents a novel GTPase-activating protein (GAP) family and is the cognate GAP of MglA. Between reversals, MglA/GTP is restricted to the leading and MglB to the lagging pole defining the leading/lagging polarity axis. For reversals, the Frz chemosensory system induces the relocation of MglA/GTP to the lagging pole causing an inversion of the leading/lagging polarity axis. MglA/GTP stimulates motility by establishing correct polarity of motility proteins between reversals and reversals by inducing their pole-to-pole relocation. Thus, the function of Ras-like G-proteins and their GAPs in regulating cell polarity is found not only in eukaryotes, but also conserved in bacteria.
Leonardy
Simone
S
Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
Miertzschke
Mandy
M
Bulyha
Iryna
I
Sperling
Eva
E
Wittinghofer
Alfred
A
Søgaard-Andersen
Lotte
L
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology; D016764:Cell Polarity; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D016941:Myxococcus xanthus / Q000166:cytology / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D020690:GTPase-Activating Proteins; D011993:Recombinant Fusion Proteins; C071728:MglA protein, Myxococcus xanthus; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate