Source:http://linkedlifedata.com/resource/umls/id/C1516396
NCI: Ceramide is a sphingosine-based lipid-signaling molecule involved in the regulation of cellular differentiation, proliferation, and apoptosis. This diagram represents some of the current understanding of the cascades that couple ceramide to specific signaling pathways. These cascades illustrate that ceramide can be a growth stimulus or proapoptotic signal. The ultimate ceramide action is determined within the context of other stimuli and by the subcellular topology of its production and is cell-type specific. There are 2 forms of sphingomyelinase, acid (acid-sphingomyelinase, A-SMase) and neutral (neutral-sphingomyelinase, N-SMase), that can produce ceramide. TNF-alpha can stimulate either form of sphingomyelinase as can other death receptors. Different domains of TNF-alpha stimulate the different SMases. N-SMase stimulation is enhanced by the receptor for activated-C kinase 1 (RACK1). The activity of each form is dependent on the local intracellular pH. In the illustration the forms are separated to red