Proteolysis of the McpA chemoreceptor does not require the Caulobacter major chemotaxis operon

The degradation of the McpA chemoreceptor in Caulobacter crescentus accompa nies the swarmer cell to the stalked-cell differentiation event. To further analyze the requirements for its degradation, we have constructed a series of strains that have deletions in the mcpA gene and in the mcpA chemotaxis operon. Internal deletions of the mcpA gene demonstrate that the highly co nserved domain (signalling unit) and the methylation domains are not requir ed for cell cycle-regulated proteolysis. The deletion of the chemotaxis ope ron, which is absolutely required for chemotaxis and McpA chemoreceptor met hylation, has no effect on McpA proteolysis.