"The plasma membrane of a neuronal cell contains protein kinase C (PKC). This neuronal cell responds to electrical stimulation from other neurons by opening calcium channels, also located at the plasma membrane. In turn, these channels allow extracellular calcium to enter the cytoplasm, greatly raising its intracellular concentration. Calcium is a potent activator of PKC. Would you expect that PKC will be activated every time the neuronal cell is stimulated?"