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Updated: Feb 23, 2026

A High-Throughput Luciferase Assay to Evaluate Proteolysis of the Single-Turnover Protease PCSK9
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A High-Throughput Luciferase Assay to Evaluate Proteolysis of the Single-Turnover Protease PCSK9

Published on: August 28, 2018

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Heparan sulfate proteoglycans present PCSK9 to the LDL receptor

Camilla Gustafsen1, Ditte Olsen2, Joachim Vilstrup3

  • 1Department of Biomedicine, Aarhus University, Ole Worms Allé 3, 8000, Aarhus, Denmark. gustafsen@biomed.au.dk.

Nature Communications
|September 13, 2017
PubMed

Insights

Researchers discovered that liver heparan sulfate proteoglycans act as receptors for PCSK9, a key protein in high cholesterol. Blocking this interaction offers a new therapeutic strategy for coronary artery disease.

Area of Science:

  • Biochemistry
  • Cardiovascular Biology
  • Molecular Medicine

Background:

  • Coronary artery disease (CAD) is a leading global cause of mortality, significantly influenced by elevated levels of low-density lipoprotein (LDL) cholesterol.
  • Circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) exacerbates CAD by promoting the degradation of the LDL receptor (LDLR) in hepatocytes, impairing LDL clearance.
  • Understanding the precise mechanisms of PCSK9 action is crucial for developing effective CAD therapies.

Purpose of the Study:

  • To identify the specific liver molecules that bind PCSK9 and mediate its effect on LDLR degradation.
  • To investigate the role of heparan sulfate proteoglycans (HSPGs) as potential receptors for PCSK9 on the liver surface.
  • To explore the therapeutic potential of targeting the PCSK9-HSPG interaction for managing hypercholesterolemia and CAD.

Main Methods:

  • Utilized biochemical assays to identify PCSK9 binding partners on the liver surface.
  • Characterized the binding site of PCSK9 for heparan sulfate using structural and mutational analyses.
  • Tested the efficacy of heparan sulfate mimetics and monoclonal antibodies targeting the PCSK9 binding site as PCSK9 inhibitors.

Main Results:

  • Demonstrated that liver heparan sulfate proteoglycans serve as essential receptors for PCSK9.
  • Identified a specific heparan sulfate-binding site within the PCSK9 prodomain, involving basic residues interacting with trisulfated heparan sulfate disaccharides.
  • Showed that heparan sulfate mimetics and antibodies blocking this site are potent inhibitors of PCSK9 activity.
  • Proposed a model where cell-surface HSPGs capture PCSK9, facilitating subsequent LDLR degradation.

Conclusions:

  • Heparan sulfate proteoglycans are critical mediators of PCSK9 function in regulating LDL receptor levels.
  • Targeting the PCSK9-heparan sulfate interaction represents a promising novel therapeutic strategy for reducing LDL cholesterol and treating coronary artery disease.

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