An amphiphilic lipid has properties that permit formation of cellular membranes. Lipids can be hydrophobic (water-hating) or amphiphilic. Lipids are a structurally diverse group of molecules and can be best defined as substances that are soluble in non-polar organic solvents (e.g. In addition to this most basic function, lipids serve as energy stores, sources of signalling molecules and platforms for protein recruitment. They are the structural components of cell membranes, without which cells (and life) would not exist. Lipids play essential functions in cellular physiology and pathology. The wide range of physiological processes in which a specific involvement of lipids has been identified explains the need for lipid diversity present in mammalian cells. Alternatively, bioactive lipids also provide a platform for reversible recruitment of proteins to membranes using their lipid-binding domains. Bioactive metabolites can be second messengers, or released to the external medium to regulate other cells. The function of individual metabolites is also highlighted. These transient bioactive metabolites allow cells to respond to the external environment to maintain cellular health. Cellular lipids are metabolised by phospholipases, lipid kinases and phosphatases to make new bioactive metabolites. Lipid synthesis is intimately connected to their transport within cells the contribution by proteins that transport lipids, lipid transport proteins will be described. The fatty acids (FAs) are the main building blocks of lipids and contribute to the diversity. This review summarises the biosynthesis of the lipids of the mammalian cell phospholipids, sphingolipids and cholesterol and how lipid diversity is achieved. Understanding lipid diversity, their synthesis and metabolism to generate signalling molecules will provide insight into the fundamental function of the cell. Lipids regulate many physiological functions of cells and alterations in membrane lipid metabolism are associated with major diseases including cancer, Type II diabetes, cardiovascular disease and immune disorders.

Once regarded merely as structural components, lipids have taken centre stage with the discovery of their roles in cell signalling and in the generation of bioactive metabolites. Lipids are essential constituents of cellular membranes.

Structure of lipids download