The glycosylation-dependent interaction of perlecan core protein with LDL: implications for atherosclerosis.

Academic Article

Abstract

  • Perlecan is a major heparan sulfate (HS) proteoglycan in the arterial wall. Previous studies have linked it to atherosclerosis. Perlecan contains a core protein and three HS side chains. Its core protein has five domains (DI-DV) with disparate structures and DII is highly homologous to the ligand-binding portion of LDL receptor (LDLR). The functional significance of this domain has been unknown. Here, we show that perlecan DII interacts with LDL. Importantly, the interaction largely relies on O-linked glycans that are only present in the secreted DII. Among the five repeat units of DII, most of the glycosylation sites are from the second unit, which is highly divergent and rich in serine and threonine, but has no cysteine residues. Interestingly, most of the glycans are capped by the negatively charged sialic acids, which are critical for LDL binding. We further demonstrate an additive effect of HS and DII on LDL binding. Unlike LDLR, which directs LDL uptake through endocytosis, this study uncovers a novel feature of the perlecan LDLR-like DII in receptor-mediated lipoprotein retention, which depends on its glycosylation. Thus, perlecan glycosylation may play a role in the early LDL retention during the development of atherosclerosis.
  • Authors

  • Xu, Yu-Xin
  • Ashline, David
  • Liu, Li
  • Tassa, Carlos
  • Shaw, Stanley Y
  • Ravid, Katya
  • Layne, Matthew D
  • Reinhold, Vernon
  • Robbins, Phillips W
  • Status

    Publication Date

  • February 2015
  • Published In

    Keywords

  • Animals
  • Atherosclerosis
  • COS Cells
  • Cell Line
  • Cercopithecus aethiops
  • Glycosylation
  • HeLa Cells
  • Heparan Sulfate Proteoglycans
  • Humans
  • Immunohistochemistry
  • Lipoproteins, LDL
  • Microscopy, Confocal
  • Mutagenesis, Site-Directed
  • N-Acetylneuraminic Acid
  • Rats
  • Receptors, LDL
  • low density lipoprotein
  • low density lipoprotein receptor
  • sialic acid
  • Digital Object Identifier (doi)

    Start Page

  • 266
  • End Page

  • 276
  • Volume

  • 56
  • Issue

  • 2