Cell surface-expressed moesin-like HDL/apoA-I binding protein promotes cholesterol efflux from human macrophages.
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.
Matsuyama
Akifumi
A
Medical Center for Translational Research, Osaka University Hospital, 2-15 Yamada-oka, Suita.
Sakai
Naohiko
N
Hiraoka
Hisatoyo
H
Hirano
Ken-ichi
K
Yamashita
Shizuya
S
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D016632:Apolipoprotein A-I / Q000378:metabolism*; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008075:Lipoproteins, HDL / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008970:Molecular Weight; D009000:Monocytes / Q000166:cytology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D016632:Apolipoprotein A-I; D002352:Carrier Proteins; D017261:Glycosylphosphatidylinositols; D008075:Lipoproteins, HDL; D008565:Membrane Proteins; D008840:Microfilament Proteins; C071058:moesin; D002784:Cholesterol