Endocytosis is not required for the selective lipid uptake mediated by murine SR-BI

Thomas J.F. Nieland, Marcelo Ehrlich, Monty Krieger, Tomas Kirchhausen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The scavenger receptor class B, type I (SR-BI) mediates the cellular selective uptake of cholesteryl esters and other lipids from high-density lipoproteins (HDL) and low-density lipoproteins (LDL). This process, unlike classical receptor-mediated endocytosis, does not result in lipoprotein degradation. Instead, the lipid depleted particles are released into the medium. Here we show that selective lipid uptake mediated by murine SR-BI can be uncoupled from the endocytosis of HDL or LDL particles. We found that blocking selective lipid uptake by incubating cells with the small chemical inhibitors BLT-1 or BLT-4 did not affect endocytosis of HDL. Similarly, blocking endocytosis by hyperosmotic sucrose or K+ depletion did not prevent selective lipid uptake from HDL or LDL. These findings suggest that mSR-BI-mediated selective uptake occurs at the cell surface upon the association of lipoproteins with mSR-BI and does not require endocytosis of HDL or LDL particles.

Original languageEnglish
Pages (from-to)44-51
Number of pages8
JournalBiochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
Volume1734
Issue number1
DOIs
StatePublished - 1 May 2005
Externally publishedYes

Funding

FundersFunder number
National Institutes of HealthHL66105, HL52212 HL48739, GM62566
National Heart, Lung, and Blood InstituteR01HL048739

    Keywords

    • BLT
    • Endocytosis
    • High-density lipoprotein
    • Low-density lipoprotein
    • Scavenger receptor
    • Scavenger receptor class B, type I

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