Figure 1.

Mechanism of lipid efflux mediated by ABCA1. ① Low-density lipoprotein binds to ABCA1 to form a complex. ② The complex is internalized, part of it is transferred to the lysosome for degradation and the rest is located to the endosome. ③ The complex on the endosome combines with lipid to form the apoA-l/lipid complex. ④ The lipid complexes are resecreted through exocytosis, and after dissociation, they are conducive to the formation of high-density lipoprotein complexes. Apo, apolipoprotein; ABC, ATP-binding cassette.