Question

How does the CheA protein affect glucose concentration levels? If the CheA protein wasn't working anymore, what would happen to your ability to respond to glucose concentrations and why?

Answer 1

CheA is a protein functioning in transmission of signals from chemoreceptors to flagellar motors on a sensory stimulus. It is a histidine kinase. It undergoes autophosphorylation, at a histidine residue in its C-terminal sequence. On sensing glucose in the surroundings, the receptor on the membrane of bacteria, signal autophosphorylation of CheA via their cytoplasmic domains. CheA then phosphorylates CheY in the downstream pathway. CheY binds to the flagellar motor, finally resulting in rotation of the flagellum. This would facilitate movement of the bacterium towards glucose which is sensed as a food source. This is called chemotaxis. Thus, if the CheA protein is not functional, the chain for signaling from receptor to flagellar motor is broken. The bacterium wouldn’t show specific movement towards the food source in such acase.