Phospholipids and Electrolyte Transport

Our understanding of the role of phospholipids in ion transport processes is only beginning to be appreciated. Although the role of polyphosphoinositide and its derived second messenger molecules IP₃, diacylglycerol, and arachidonic acid are well studied, we are still not certain as to how changes in the lipid bilayer structure influence the status of ion channels. This review focused on those studies which show a strong correlation with ion conductance changes and the status of the membrane phospholipids. In addition, a number of observations point to a major role of lipid second messengers that activate enzymes involved in protein phosphorylations, i.e., protein kinase C, as major regulators of a variety of ion channels and transporters. Such lipid second messengers provide a cellular mechanism whereby hormones, neurotransmitters, and pharmacologic agents functionally control the ionic environment and intracellular pH of target cells. Some of these pathways still remain to be elucidated; however, an appreciation for the participation of membrane phospholipids in these actions has been presented.