Cholesterol metabolism: increasingly complex

Cholesterol metabolism: increasingly complex. Cholesterol is an important molecule; it is necessary for the biosynthesis of steroidal hormones, bile salts and to maintain the stability of biological membranes in animal cells. However, its excess is negative and is responsible for the development of many diseases involving the heart and brain, or in the generation of some types of cancer. For these reasons, the cellular cholesterol levels must be finely regulated and therefore, an infinite number of mechanisms participate in this regulation, which undertake the organism as a whole. These mechanisms should begin to operate efficiently from the intake of cholesterol from the diet, its incorporation into the enterocyte, where are involved carriers such as ABC and NCP1 transporters, PDZ structural motif, to name a few. It is also necessary an adequate regulation of circulating cholesterol and once inside the body, there should be a perfect harmony between the addition of cholesterol to various tissues, its metabolic use, the mechanisms of its tissue deposition, and the synthesis of this lipid. From this perspective, this review offers a general view of the molecular mechanisms that allow the regulation of extra and intracellular cholesterol levels.