Inorganic polyphosphate in the social life of Myxococcus xanthus : Motility, development, and predation

doi:10.1073/pnas.0506520102

Inorganic polyphosphate in the social life of Myxococcus xanthus: Motility, development, and predation

Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307

Contributed by Arthur Kornberg, August 4, 2005

Abstract

Inorganic polyphosphate (poly P), a polymer of tens or hundreds of phosphate residues linked by high-energy, ATP-like bonds, is found in all organisms and performs a wide variety of functions. Myxococcus xanthus, a social bacterium that feeds on other bacteria and forms fruiting bodies and spores, depends on poly P for motility, development, and nutritional predation. Two poly P metabolizing enzymes were studied in M. xanthus: poly P kinase 1, which synthesizes poly P reversibly from ATP, and poly P:AMP phosphotransferase, which uses poly P as a donor to also reversibly convert AMP to ADP. The null mutant of ppk1 is defective in social motility, overproduces pilin protein on the cell surface, is delayed in fruiting body formation, produces fewer spores, is delayed in germination, and forms far smaller plaques on a lawn of Klebsiella aerogenes. The pap mutant is also impaired in social motility, but shows only slightly reduced abilities in development and predation.

Footnotes

↵ † To whom correspondence should be addressed at: Department of Biochemistry, Stanford University School of Medicine, B415 Beckman Center, 279 Campus Drive West, Stanford, CA 94305-5307. E-mail: akornber{at}cmgm.stanford.edu.
↵ * Present address: Regenetiss, 1-9-4, Asahigaoka, Hino, Tokyo 191-0065, Japan.
Abbreviations: poly P, inorganic polyphosphate; PPK1, polyphosphate kinase 1; PAP, poly P:AMP phosphotransferase; A-motility, adventurous motility; S-motility, social motility; TFP, type IV pili; EPS, exopolysaccharide.
Data deposition: The sequences of M. xanthus pap and ppk1 reported in this paper have been deposited in the GenBank database (accession nos. DQ091855 and DQ091856).