title: The β-chain of cell surface F(0)F(1) ATPase modulates apoA-I and HDL transcytosis through aortic endothelial cells.
abstract: OBJECTIVE
  Both HDLs and their major protein constituent apolipoprotein A-I (apoA-I) are transported through aortic endothelial cells. The knock-down of the ATP-binding cassette transporters A1 (ABCA1), G1 (ABCG1), and of the scavenger receptor-BI (SR-BI) diminishes but does not completely block the transport of apoA-I or HDL, so that other receptors appear to be involved. The ectopic β-chain of F(0)F(1) ATPase has been previously characterized as an apoA-I receptor, triggering HDL internalization in hepatocytes.
  
  
  RESULTS
  The ectopic presence of the β-chain of F(0)F(1) ATPase on the surface of endothelial cells was confirmed by cell surface biotinylation. RNA-interference and the F(0)F(1) ATPase inhibitory peptide IF(1) reduced cell binding of apoA-I but not HDL, as well as association and transendothelial transport of both apoA-I and HDL. Furthermore, apoA-I stimulated F(0)F(1) ATPase catalyzed ATP hydrolysis. The generated ADP as well as apoA-I stimulated the binding, cell association, and internalization of HDL. Both in the presence and absence of ADP inhibition of the purinergic receptor P2Y(12) but not P2Y(1) decreased the cell association of apoA-I and HDL. Coinhibition of β-ATPase and ABCA1 had no additive effects on the cell association and transport of apoA-I. Reduced cell association of HDL by β-ATPase inhibition was not further decreased by additional knock-down of ABCG1 or SR-BI.
  
  
  CONCLUSIONS
  Binding of apoA-I to ectopic F(0)F(1) ATPase triggers the generation of ADP, which via activation of the purinergic receptor P2Y(12) stimulates the uptake and transport of HDL and initially lipid-free apoA-I by endothelial cells.
authors: Institute of Clinical Chemistry, University and University Hospital Zurich, Zurich, Switzerland.
authors: Clara
authors: C
authors: Cavelier
authors: Pascale M
authors: PM
authors: Ohnsorg
authors: Lucia
authors: L
authors: Rohrer
authors: Arnold
authors: A
authors: von Eckardstein
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D016632:Apolipoprotein A-I / Q000378:metabolism*; D001483:Base Sequence; D018955:CD36 Antigens / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004705:Endocytosis; D042783:Endothelial Cells / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000378:metabolism*; D008954:Models, Biological; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D058925:Receptors, Purinergic P2Y12 / Q000378:metabolism; D057900:Transcytosis
chemical_list: D018528:ATP-Binding Cassette Transporters; D016632:Apolipoprotein A-I; D018955:CD36 Antigens; D008075:Lipoproteins, HDL; D034741:RNA, Small Interfering; D058925:Receptors, Purinergic P2Y12; D000244:Adenosine Diphosphate; D006180:Proton-Translocating ATPases