The cyanobacterial taxis protein HmpF regulates type IV pilus activity in response to light
Thomas V. Harwood, Esthefani G. Zuniga, HoJun Kweon, Douglas D. Risser
Abstract
Significance Many photosynthetic cyanobacteria are capable of migrating in response to light in a process known as phototaxis. In all of the cyanobacteria where this process has been characterized at the genetic and molecular level, motility has been shown to be powered by type IV pili and influenced by chemotaxis-like systems with methyl-accepting chemotaxis proteins containing light-sensing GAF domains. However, the means by which the light-sensing systems modulate T4P activity has not been defined. In this study we provide evidence that cyanobacteria possess a second, distinct system for sensing light, the Hmp chemotaxis-like system, which lacks a GAF domain and modulates direct interaction between the cyanobacterial taxis protein HmpF and the T4P to regulate motility in response to light.