title: FrzS regulates social motility in Myxococcus xanthus by controlling exopolysaccharide production.
abstract: Myxococcus xanthus Social (S) motility occurs at high cell densities and is powered by the extension and retraction of Type IV pili which bind ligands normally found in matrix exopolysaccharides (EPS). Previous studies showed that FrzS, a protein required for S-motility, is organized in polar clusters that show pole-to-pole translocation as cells reverse their direction of movement. Since the leading cell pole is the site of both the major FrzS cluster and type IV pilus extension/retraction, it was suggested that FrzS might regulate S-motility by activating pili at the leading cell pole. Here, we show that FrzS regulates EPS production, rather than type IV pilus function. We found that the frzS phenotype is distinct from that of Type IV pilus mutants such as pilA and pilT, but indistinguishable from EPS mutants, such as epsZ. Indeed, frzS mutants can be rescued by the addition of purified EPS, 1% methylcellulose, or co-culturing with wildtype cells. Our data also indicate that the cell density requirement in S-motility is likely a function of the ability of cells to construct functional multicellular clusters surrounding an EPS core.
authors: Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America.
authors: James E
authors: JE
authors: Berleman
authors: Juan J
authors: JJ
authors: Vicente
authors: Annie E
authors: AE
authors: Davis
authors: Sharon Y
authors: SY
authors: Jiang
authors: Young-Eun
authors: YE
authors: Seo
authors: David R
authors: DR
authors: Zusman
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology*; D056265:Microbial Interactions; D016941:Myxococcus xanthus / Q000502:physiology*; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D053038:Quorum Sensing
chemical_list: D001426:Bacterial Proteins; C415990:FrzS protein, Myxococcus xanthus; D011135:Polysaccharides, Bacterial