Orphan Hybrid Histidine Protein Kinase SinK Acts as a Signal Integrator To Fine-Tune Multicellular Behavior in Myxococcus xanthus

Biofilms are multicellular communities of microorganisms that play important roles in host disease or environmental biofouling. Design of preventative strategies to block biofilms depends on understanding the molecular mechanisms used by microorganisms to build them. The production of biofilms in bacteria often involves two-component signal transduction systems in which one protein component (a kinase) detects an environmental signal and, through phosphotransfer, activates a second protein component (a response regulator) to change the transcription of genes necessary to produce a biofilm. We show that an atypical kinase, SinK, modulates several distinct stages of specialized biofilm produced by the environmental bacteriumMyxococcus xanthus . SinK likely integrates multiple signals to fine-tune biofilm formation in response to distinct environmental conditions.