Inositol lipids and second messengers

We have already seen how the two products of phosphatidylinositol bisphosphate hydrolysis can interact through their cellular effects. A good example is liver, where the inositol 1,4,5-triphosphate/Ca pathway controls the activity of phosphorylase kinase whereas the diacylglycerol/ protein kinase C pathway switches off glycogen synthetase. 

Considering the explosion of interest in and knowledge gained about phosphoinositides in the last ten years, it will not be surprising if many other fascinating aspects are uncovered in the next decade. 

9 ROLE OF LIPIDS IN IMMUNITY LIPIDS PLAY A ROLE IN IMMUNITY BY INFLUENCING THE PROPERTIES OF MEMBRANES IN CELLS OF THE IMMUNE SYSTEM AND BY ACTING AS PRECURSORS OF REGULATORY SUBSTANCES 

Lipids can be involved in immunity in a number of ways, principally through their roles in membrane integrity and in providing precursors for eicosanoid formation. Thus, the proliferation of lymphocytes involves rapid synthesis of new membranes the interaction of antigens with receptors on the lymphocyte surface is influenced by the physico-chemical properties of the membrane (sections 6.5.4 and 8.1) and the eicosanoids play a key role in inflammatory reactions. Dietary lipids may modulate immune reactions, therefore, either by modifying the composition of cell membranes and membrane surface components or by influencing the nature of the precursor pool for eicosanoids. 

The glycosphingolipid content of plasma membranes and, hence, their antigenicity changes during embryogenesis and differentiation. The embryonic stage-specific substances have been postulated to regulate cell 

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