Cell surface-expressed moesin-like HDL/apoA-I binding protein promotes cholesterol efflux from human macrophages

• Main Authors: Akifumi Matsuyama, Naohiko Sakai, Hisatoyo Hiraoka, Ken-ichi Hirano, Shizuya Yamashita
• Format: Article
• Language: English
• Published: Elsevier 2006-01-01
• Series: Journal of Lipid Research
• Subjects: apolipoprotein A-I; glycosylphosphatidylinositol-anchored protein; moesin-like protein; atherosclerosis
• Online Access: http://www.sciencedirect.com/science/article/pii/S0022227520336579

HDL and its major component, apolipoprotein A-I (apoA-I), play a central role in reverse cholesterol transport. We recently reported the involvement of a glycosylphosphatidylinositol anchor (GPI anchor) in the binding of HDL and apoA-I on human macrophages, and purified an 80 kDa HDL/apoA-I binding protein. In the present study, we characterized the GPI-anchored HDL/apoA-I binding protein from macrophages. The HDL/apoA-I binding protein was purified from macrophages and digested with endopeptidase, and the resultant fragments were sequenced. Cholesterol efflux, flow cytometry, immunoblotting, and immunohistochemical analyses were performed to characterize the HDL/apoA-I binding protein. Two parts of seven amino acid sequences completely matched those of moesin. Flow cytometry, immunoblotting, and immunohistochemistry using anti-moesin antibody showed that the HDL/apoA-I binding protein was N-glycosylated and expressed on the cell surface. It was termed moesin-like protein. Treatment of macrophages with anti-moesin antibody blocked the binding of HDL/apoA-I and suppressed cholesterol efflux. The moesin-like protein was exclusively expressed on macrophages and was upregulated by cholesterol loading and cell differentiation. Our results indicate that the moesin-like HDL/apoA-I binding protein is specifically expressed on the surface of human macrophages and promotes cholesterol efflux from macrophages.—Matsuyama, A, N. Sakai, H. Hiraoka, K-i. Hirano, and S. Yamashita. Cell surface-expressed moesin-like HDL/apoA-I binding protein promotes cholesterol efflux from human macrophages.