Membrane Lipid Signaling In Aging and Age-related Disease

The lipids that comprise membranes of cells, be they phospholipids, sphingolipids, glycolipids or even cholesterol, serve many functions beyond their role in the structural organization of the membranes. In response to stimulation by various agonists, and environmental insults such as oxidative stress, several different membrane lipids are cleaved either enzymatically or non-enzymatically. Products are thereby released that act as important signals mediating physiological responses to the stimuli. Among the most intensively studied signaling pathways is the inositol phospholipid signaling, which leads to the production of IP3 and diacylglycerol with consequent calcium release and protein kinase activation. Another example of a prominent signaling pathway involves sphingomyelin hydrolysis resulting in the production of ceramide, which acts as an important signal in both physiological and pathophysiological settings.