The Golgi association of endothelial nitric oxide synthase is necessary for the efficient synthesis of nitric oxide

The particulate enzyme, endothelial nitric oxide synthase (eNOS), produces nitric oxide to maintain normal vasodilator tone in blood vessels. In this study, we demonstrate that eNOS is a Golgi-associated protein in cultured endothelial cells and intact blood vessels. Using a heterologous expression system in HEK 293 cells, we show that wild-type myristoylated and palmitoylated eNOS, but not mutant, non-acylated eNOS targets to the Golgi. More importantly, HEK 293 cells expressing wild-type eNOS release substantially more NO than cells expressing the mutant, non-acylated enzyme. Thus, eNOS is a novel Golgi-associated protein, and Golgi compartmentalization is necessary for the enzyme to respond to intracellular signals and produce NO.