S-nitrosylation of NSF controls membrane trafficking.

Nitric oxide is a diffusible molecule with profound effects on regulated exocytosis in several biological systems-however, the molecular targets remain elusive. In this issue of Cell, Matsushita et al. report that in aortic endothelial cells, S-nitrosylation of NSF, an ATPase essential for the activation of the membranefusion machinery, inhibits the exocytosis of Weibel-Palade bodies, secretory granules containing a cocktail of mediators essential to the regulation of vascular vessel tone.