Sphingomyelinase-MAPK activation

Injury to cell plasma membrane can activate acid sphingomyelinase to break down membrane lipid sphingomyelin and generate the second messenger ceramide, a complex lipid, to initiate the apoptosis (HI). Ceramide, perhaps through intracellular mitogen-activated protein kinases (MAPK), can alter cellular susceptibility to TNF-a, FasL, and ionizing radiation-induced apoptosis (HI, Wll). 

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