apoA1

Apolipoprotein A-I (apoA1) is the principal protein component of high-density lipoprotein (HDL) and a key mediator of plasma cholesterol transport and cellular cholesterol homeostasis^[1][2]. ApoA1 initiates and sustains reverse cholesterol transport by accepting cellular cholesterol and phospholipids through interactions with ATP-binding cassette transporters, particularly ABCA1, thereby promoting nascent HDL formation and cholesterol efflux from peripheral tissues^[2][3][4]. During HDL maturation, apoA1 functions as an essential cofactor for lecithin-cholesterol acyltransferase (LCAT), facilitating cholesterol esterification and the generation of mature HDL particles that support systemic cholesterol trafficking^[2][5]. Mechanistically, apoA1 interacts with ABCA1, ABCG1, and scavenger receptor class B type I (SR-B1), placing it at the center of HDL metabolism and reverse cholesterol transport pathways^[2][4]. In cardiovascular disease models, apoA1 and HDL contribute to atheroprotection by promoting cholesterol removal and limiting low-density lipoprotein deposition within the vascular wall^[6][7]. Compared with related apolipoproteins such as apoA-II, apoA1 serves as the predominant structural and functional component of HDL and participates in nearly all established HDL biological activities^[8][9]. For experimental applications, apoA1 variants and apoA1-mimetic particles have been used to investigate cholesterol efflux, HDL function, and anti-atherosclerotic mechanisms, with the apoA1-Milano variant showing enhanced interaction with SR-B1 and stronger inhibition of low-density lipoprotein deposition in preclinical studies^[6].

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