Multicellular organisms must be able to adapt to cellular events to accommodate prevailing conditions. Sensory-response circuits operate by making use of a phosphorylation control mechanism known as the "two-component system." Sections include: Computational Analyses of Sequences and Sequence Alignments Biochemical and Genetic Assays of Individual Components of Signaling Systems Physiological Assays and Readouts - Presents detailed protocols - Includes troubleshooting tips