Uptake of oxidized low density lipoprotein by CD36 occurs by an actin-dependent pathway distinct from macropinocytosis

J Biol Chem. 2009 Oct 30;284(44):30288-97. doi: 10.1074/jbc.M109.045104. Epub 2009 Sep 9.

Abstract

The class B scavenger receptor CD36 has numerous ligands that include modified forms of low density lipoprotein, fibrillar amyloid, apoptotic cells, and Plasmodium falciparum-infected red blood cells, linking this molecule to atherosclerosis, Alzheimer disease, malaria, and other diseases. We studied the signaling events that follow receptor engagement and lead to CD36 and ligand internalization. We show that oxidized low density lipoprotein or antibody-induced clustering of CD36 triggers macropinocytosis and internalization of the receptor-ligand complex. Remarkably, however, CD36 internalization is independent of macropinocytosis and occurs by a novel endocytic mechanism that depends on actin, but not dynamin. This actin-driven endocytosis requires the activation Src family kinases, JNK, and Rho family GTPases, but, unlike macropinocytosis, it is not affected by inhibitors of phosphatidylinositol 3-kinase or Na/H exchange. Manipulation of this unique mode of internalization may prove helpful in the prevention and management of the wide range of diseases in which CD36 is implicated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism*
  • CD36 Antigens / physiology*
  • Cells, Cultured
  • Humans
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Lipoproteins, LDL / metabolism*
  • Macrophages / cytology
  • Macrophages / metabolism
  • Pinocytosis*
  • Signal Transduction*
  • rho GTP-Binding Proteins / metabolism
  • src-Family Kinases / metabolism

Substances

  • Actins
  • CD36 Antigens
  • Lipoproteins, LDL
  • oxidized low density lipoprotein
  • src-Family Kinases
  • JNK Mitogen-Activated Protein Kinases
  • rho GTP-Binding Proteins