Energy and information transduction of bacteria flagellar motor of chimeric cell

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An Escherichia coli cell transduces extracellular stimuli sensed by chemoreceptors to the state of an intracellular signal molecule, which regulates switching of the rotational direction of the flagellar motors from counterclockwise (CCW) to clockwise (CW). Here, we performed high-speed imaging of flagellar motor rotation and showed that the switching of two different motors on a cell is controlled coordinately by an intracellular signal protein, phosphorylated CheY (CheY-P). The switching is highly coordinated, with a sub-second delay between motors that is correlated with the distance of each motor from the chemoreceptor patch, which is localized at the cell pole. The coordinated switching was disordered by the expression of constitutively active CheY protein, which mimics the CW-rotation stimulating function. Also, the coordinated switching was required the CheZ, which is a phosphatase for CheY-P. Our results suggest that a transient increase and decrease in the concentration of a signal protein from the chemoreceptor patch, which is probably a wave-like change in under a second, triggers and regulates the coordinated switching of flagellar motors. We firstly measured the propagation of intracellular signaling in a single bacterial cell by applying the simultaneous measurement for the rotation of multiple flagellar motors.