ReviewMolecular Mechanisms of Signaling in Myxococcus xanthus Development

- M. xanthus displays elaborate development, forming multicellular fruiting bodies.
- Extensive gene duplication led to an expansion of signaling proteins in M. xanthus.
- Fruiting body formation is an obligate multicellular process and is kin selective.
- Single-cell regulation is mediated by the stringent response and several two-component signaling systems.
- Development at the population level is regulated by a series of extracellular cues.

Myxococcus xanthus is an environmental bacterium that displays a complex life cycle that includes motility, predation, multicellular fruiting body development, and sporulation. Given the elaborate fruiting body development of this bacterial species, M. xanthus has served as a model organism for the study of multicellular development of bacteria, and a remarkable number of genes have been identified that contribute to the regulation of this highly dynamic process. Included among these developmental factors is a robust repertoire of signaling proteins, which have arisen from extensive gene duplication in M. xanthus and related species. In this review, we explore several aspects of the molecular mechanisms of signaling in M. xanthus development. This includes mechanisms of kin selection, single-cell sensing of nutrient depletion and the stringent response, the production of and response to extracellular population cues, and the contribution of several two-component signaling systems regulating developmental transcriptional programs. Collectively, these signaling mechanisms function to tightly regulate the sensing of nutrient depletion, the aggregation of populations of cells, and the temporal and spatial formation of complex fruiting bodies and sporulation of M. xanthus.

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