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10:08

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A PEST sequence in ABCA1 regulates degradation by calpain protease and stabilization of ABCA1 by apoA-I

Nan Wang1, Wengen Chen, Patrick Linsel-Nitschke

  • 1Division of Molecular Medicine, Department of Medicine, Columbia University, New York, New York 10032, USA. nw30@columbia.edu

The Journal of Clinical Investigation
|January 4, 2003
PubMed

Insights

Apolipoprotein A-I (apoA-I) binding to ABCA1 cholesterol transporter enhances lipid efflux and cell survival. This discovery offers a new therapeutic strategy for atherosclerosis by inhibiting ABCA1 degradation.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Molecular Medicine

Background:

  • Cholesterol-loaded macrophage foam cells are key in atherosclerosis.
  • ATP-binding cassette transporter A1 (ABCA1) facilitates cholesterol efflux to apolipoprotein A-I (apoA-I), reversing foam cell formation.
  • ABCA1 dysfunction causes Tangier disease.

Purpose of the Study:

  • To investigate the regulatory mechanisms of ABCA1 activity and stability.
  • To explore the role of the PEST sequence in ABCA1 degradation.
  • To identify potential therapeutic targets for atherosclerosis.

Main Methods:

  • Identification of a PEST sequence within ABCA1.
  • Assessing ABCA1 degradation by calpain protease.
  • Investigating the effect of apoA-I binding on ABCA1 levels and activity.
  • In vivo studies involving apoA-I infusion.

Main Results:

  • A PEST sequence in ABCA1 enhances its degradation by calpain protease, controlling cell surface levels and cholesterol efflux.
  • ApoA-I binding to ABCA1 promotes lipid efflux, inhibits calpain-mediated degradation, and increases ABCA1 levels.
  • In vivo apoA-I infusion also elevates ABCA1 levels.

Conclusions:

  • ABCA1 regulation involves PEST sequence-mediated calpain proteolysis, counteracted by apoA-I-mediated lipid efflux.
  • Inhibiting calpain-dependent ABCA1 degradation presents a novel therapeutic strategy for increasing macrophage cholesterol efflux and reducing atherosclerosis.

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