Cholesterol binding, efflux, and a PDZ-interacting domain of scavenger receptor-BI mediate HDL-initiated signaling

Chatchawin Assanasen, Chieko Mineo, Divya Seetharam, Ivan S. Yuhanna, Yves L. Marcel, Margery A. Connelly, David L. Williams, Margarita De La Llera-Moya, Philip W. Shaul, David L. Silver

Research output: Contribution to journalArticle

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Abstract

The binding of HDL to scavenger receptor-BI (SR-BI) mediates cholesterol movement. HDL also induces multiple cellular signals, which in endothelium occur through SR-BI and converge to activate eNOS. To determine the molecular basis of a signaling event induced by HDL, we examined the proximal mechanisms in HDL activation of eNOS. In endothelial cells, HDL and methyl-β-cyclodextrin caused comparable eNOS activation, whereas cholesterol-loaded methyl-β-cyclodextrin had no effect. Phosphatidylcholine-loaded HDL caused greater stimulation than native HDL, and blocking antibody against SR-BI, which prevents cholesterol efflux, prevented eNOS activation. In a reconstitution model in COS-M6 cells, wild-type SR-BI mediated eNOS activation by both HDL and small unilamellar vesicles (SUVs), whereas the SR-BI mutant AVI, which is incapable of efflux to SUV, transmitted signal by only HDL. In addition, eNOS activation by methyl-β-cyclodextrin was SR-BI dependent. Studies of mutant and chimeric class B scavenger receptors revealed that the C-terminal cytoplasmic PDZ-interacting domain and the C-terminal transmembrane domains of SR-BI are both necessary for HDL signaling. Furthermore, we demonstrated direct binding of cholesterol to the C-terminal transmembrane domain using a photoactivated derivative of cholesterol. Thus, HDL signaling requires cholesterol binding and efflux and C-terminal domains of SR-BI, and SR-BI serves as a cholesterol sensor on the plasma membrane.

Original languageEnglish (US)
Pages (from-to)969-977
Number of pages9
JournalJournal of Clinical Investigation
Volume115
Issue number4
DOIs
StatePublished - Apr 2005

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PDZ Domains
Scavenger Receptors
Cholesterol
Cyclodextrins
Unilamellar Liposomes
Class B Scavenger Receptors
Blocking Antibodies
COS Cells
Endothelium
Endothelial Cells
Cell Membrane

ASJC Scopus subject areas

  • Medicine(all)

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Cholesterol binding, efflux, and a PDZ-interacting domain of scavenger receptor-BI mediate HDL-initiated signaling. / Assanasen, Chatchawin; Mineo, Chieko; Seetharam, Divya; Yuhanna, Ivan S.; Marcel, Yves L.; Connelly, Margery A.; Williams, David L.; De La Llera-Moya, Margarita; Shaul, Philip W.; Silver, David L.

In: Journal of Clinical Investigation, Vol. 115, No. 4, 04.2005, p. 969-977.

Research output: Contribution to journalArticle

Assanasen, C, Mineo, C, Seetharam, D, Yuhanna, IS, Marcel, YL, Connelly, MA, Williams, DL, De La Llera-Moya, M, Shaul, PW & Silver, DL 2005, 'Cholesterol binding, efflux, and a PDZ-interacting domain of scavenger receptor-BI mediate HDL-initiated signaling', Journal of Clinical Investigation, vol. 115, no. 4, pp. 969-977. https://doi.org/10.1172/JCI200523858
Assanasen, Chatchawin ; Mineo, Chieko ; Seetharam, Divya ; Yuhanna, Ivan S. ; Marcel, Yves L. ; Connelly, Margery A. ; Williams, David L. ; De La Llera-Moya, Margarita ; Shaul, Philip W. ; Silver, David L. / Cholesterol binding, efflux, and a PDZ-interacting domain of scavenger receptor-BI mediate HDL-initiated signaling. In: Journal of Clinical Investigation. 2005 ; Vol. 115, No. 4. pp. 969-977.
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AU - Assanasen, Chatchawin

AU - Mineo, Chieko

AU - Seetharam, Divya

AU - Yuhanna, Ivan S.

AU - Marcel, Yves L.

AU - Connelly, Margery A.

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AU - Shaul, Philip W.

AU - Silver, David L.

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