(56g) Proprioception in Bacteria (Invited Speaker)

Motile bacteria employ tactile sensors to sense their adhesion to surfaces. Surface sensing triggers signaling pathways that induce the formation of biofilms, mediate the uptake of extracellular genetic material, and promote infections by bacteria. Among the major tactile sensors, also termed as mechanosensors, is the flagellum. A tiny electric motor rotates the flagellum to propel the cell. The flagellar motor exhibits a staggering diversity of functions, which include thermal sensing, chemical sensing, mechanosensing, motility and chemotactic migration. I will discuss our recent discoveries, which suggest that the flagellar motor is involved in sensing the cell’s position and swimming speeds – also known as proprioception in higher organisms. I will discuss how membrane-bound mechanosensors in the motor detect extracellular mechanical stimuli and in response, tune the sensitivity of the chemotaxis signaling network to novel chemical stimuli via long-range allosteric mechanisms. This particular flagellar function appears to be critical for chemotaxis, and especially when the cell enters a highly-viscous environment such as the gastric mucosa. Also, it is likely to be critical for surface sensing, genetic competence, and surface colonization. Proprioceptive feedback has previously been described only in plants and animals, especially, in the neuromuscular systems of insects and vertebrates. Ours is the first report of proprioception in prokaryotes.