The LOX-1 scavenger receptor cytoplasmic domain contains a transplantable endocytic motif

Biochem Biophys Res Commun. 2009 May 29;383(2):269-74. doi: 10.1016/j.bbrc.2009.04.012. Epub 2009 Apr 7.

Abstract

Oxidized low-density lipoprotein particles is a pro-atherogenic factor implicated in atherosclerotic plaque formation. The LOX-1 scavenger receptor binds OxLDL and is linked to atherosclerotic plaque initiation and progression. We tested the hypothesis that the LOX-1 cytoplasmic domain contains a transplantable signal for membrane protein endocytosis. Structural modeling of the LOX-1 cytoplasmic domain reveals that a tripeptide motif (DDL) implicated in LOX-1 endocytosis is part of a curved beta-pleated sheet structure. The two aspartic acid residues within this structural model are highly solvent-accessible enabling recognition by cytosolic factor(s). A triple alanine substitution of the DDL motif within the LOX-1 scavenger receptor substantially reduced endocytosis of OxLDL. Transplantation of the LOX-1 cytoplasmic domain into a transferrin receptor reporter molecule conferred efficient endocytosis on this hybrid protein. Mutation of the DDL motif within the hybrid LOX-1-TfR protein also substantially reduced receptor-mediated endocytosis. Thus a transplantable endocytic motif within the LOX-1 cytoplasmic domain is needed to ensure efficient internalization of pro-atherogenic OxLDL particles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs / genetics
  • Amino Acid Sequence
  • Cytoplasm / chemistry
  • Cytoplasm / metabolism
  • Endocytosis*
  • Humans
  • Lipoproteins, LDL / metabolism*
  • Molecular Sequence Data
  • Protein Structure, Tertiary / genetics
  • Scavenger Receptors, Class E / chemistry
  • Scavenger Receptors, Class E / genetics
  • Scavenger Receptors, Class E / metabolism*

Substances

  • Lipoproteins, LDL
  • OLR1 protein, human
  • Scavenger Receptors, Class E
  • oxidized low density lipoprotein