Protein Kinase C Peptide Substrate is targeted to a specific cellular compartment in a manner dependent on second messengers and on specific adapter proteins in response to extracellular signals that activate G-protein-coupled receptors, tyrosine kinase receptors, or tyrosine kinase-coupled receptors. Protein Kinase C Peptide Substrate then regulates various physiological functions including the activation of nervous, endocrine, exocrine, inflammatory, and immune systems^[1].