Intracellular transport of low density lipoprotein derived free cholesterol begins at clathrin-coated pits and terminates at cell surface caveolae

Biochemistry. 1996 Nov 26;35(47):14932-8. doi: 10.1021/bi9613382.

Abstract

Free cholesterol (FC) is selectively internalized from low-density lipoprotein (LDL) by confluent fibroblast monolayers (Fielding & Fielding (1995) Biochemistry 34, 14237-14244). The kinetics of transport of LDL-derived 3H-FC within the cell were studied by density-gradient ultracentrifugal fractionation and in terms of the effects of inhibitors of endocytosis and intracellular transport. By these criteria, the initial uptake of LDL-FC was mediated by the cell-surface clathrin-coated pits. FC label then appeared in clathrin-coated dense vesicles. Uncoating of clathrin from these vesicles led to the appearance of label in a light density fraction and, subsequently, in an intermediate density fraction coincident with protein markers of the trans-Golgi network in these cells. 3H-FC was finally transported to the plasma membrane via a temperature-sensitive, probably microtubule-dependent pathway. These data are consistent with a role for the trans-Golgi network as an intermediate compartment in intracellular FC transport. They provide further evidence of a role for cell-surface caveolae in FC efflux.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Biological Transport / drug effects
  • Cell Line
  • Cell Membrane / metabolism
  • Centrifugation, Density Gradient
  • Cholesterol, LDL / metabolism*
  • Clathrin / metabolism*
  • Coated Pits, Cell-Membrane / metabolism*
  • Cytochalasin D / pharmacology
  • Humans
  • Lipoproteins / metabolism
  • Macrolides*
  • Monensin / pharmacology
  • Nocodazole / pharmacology
  • Subcellular Fractions / metabolism

Substances

  • Anti-Bacterial Agents
  • Cholesterol, LDL
  • Clathrin
  • Lipoproteins
  • Macrolides
  • bafilomycin A
  • Cytochalasin D
  • Monensin
  • Nocodazole