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Apolipoprotein A-I directly interacts with extracellular domain 1 of human ABCA1.

Authors :
Kawanobe, Takaaki
Shiranaga, Naoko
Kioka, Noriyuki
Kimura, Yasuhisa
Ueda, Kazumitsu
Source :
Bioscience, Biotechnology & Biochemistry. Mar2019, Vol. 83 Issue 3, p490-497. 8p.
Publication Year :
2019

Abstract

ATP-binding cassette transporter A1 (ABCA1) is critical for the generation of nascent high-density lipoprotein (HDL) and plays important roles in cholesterol homeostasis. ABCA1 has two large extracellular domains (ECDs), which may interact directly with apolipoprotein A-I (apoA-I). However, the molecular mechanisms underlying HDL formation and the importance of ABCA1-apoA-I interactions in HDL formation remain unclear. We investigated the ABCA1-apoA-I interaction in photo-activated crosslinking experiments using sulfo-SBED-labeled apoA-I. ApoA-I bound to cells expressing ABCA1, but not to untransfected cells or cells expressing non-functional ABCA1. Binding was inhibited by sulfo-SBED-labeled apoA-I, and crosslinking of sulfo-SBED-labeled apoA-I with ABCA1 was inhibited by non-labeled apoA-I, suggesting that sulfo-SBED-labeled apoA-I specifically binds and crosslinks with functional ABCA1. Proteolytic digestion of crosslinked ABCA1 revealed that apoA-I bound the N-terminal half of ABCA1, and that the first ECD of ABCA1 is an apoA-I binding site. Abbreviations: ABC: ATP-binding cassette; apoA-I: apolipoprotein A-I; ATP: adenosine triphosphate; CHAPS: 3-(3-cholamidepropyl)dimethylammonio-1- propanesulphonate; DTT: dithiothreitol; ECD: extra cellular domain; EDTA: ethylenediaminetetraacetic acid; GFP: green fluorescent protein; HA: hemagglutinin; HDL: high density lipoprotein; HEK: human embryonic kidney; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; sulfo-SBED: (sulfosuccinimidyl-2-[6-(biotinamido)-2-(p-azidobenzamido)hexanoamido] ethyl-1,3สน-dithiopropionate; NHS-ester, N-hydroxysuccinimide-ester [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09168451
Volume :
83
Issue :
3
Database :
Academic Search Index
Journal :
Bioscience, Biotechnology & Biochemistry
Publication Type :
Academic Journal
Accession number :
134716521
Full Text :
https://doi.org/10.1080/09168451.2018.1547106