The sphingomyelin (SM) pathway is an ubiquitous, evolutionarily conserved signaling
system, analogous to conventional systems such as the cAMP and phosphoinositide
pathways. Ceramide is generated from SM by the action of a neutral or acid SMase, or by de
novo synthesis coordinated through the enzyme ceramide synthase. Once generated,
ceramide may serve as a second messenger in signaling responses to physiologic or
environmental stimuli, or may be converted to a variety of structural or effector molecules. In …