Apolipoproteina A-I: estructura y funciones

GARDA, H. A.; TRICERRI, M. A.; TOLEDO, J. D.; CORSICO B; GONZALEZ, MARINA CECILIA; PRIETO, E. D.

Academia Nacional de Ciencias de Buenos Aires

Lugar: Buenos Aires; Año: 2005 vol. 66 p. 7 - 25

Apolipoprotein A-I (apoAI) plays a key role and is responsible for very important functions in “reverse cholesterol transport” (RCT), a process with great antiatherogenic relevance producing the removal and elimination of cholesterol excess in peripheral tissues. This protein of 28.1 kD (243 residues) is formed near exclusively by amphipathic a-helices and presents a large conformational flexibility, which is crucial for its ability to adopt different states (free or bound to membranes or to a variety of lipoproteic complexes of different size, composition and morphology). In this report, the structural aspects of this protein and its lipoproteic complexes are discussed in relationship with their function in RCT. In particular, studies of our laboratory on the structure and function of a central apoAI domain containing two amplhipathic helices with a particular charge distribution are described. The results of these studies indicate that this domain is responsible for anchoring discoidal HDL to cholesterol-rich membranes and to facilitate the cholesterol exchange between them, as well as for triggering in cells the mobilization toward the plasma membrane of intracellular cholesterol depots, as that available to be esterified.