Vesicular and non-vesicular sterol transport in living cells: The endocytic recycling compartment is a major sterol storage organelle Academic Article uri icon

Overview

MeSH Major

  • Ergosterol
  • Sterols
  • Transport Vesicles

abstract

  • We examined the intracellular transport of sterol in living cells using a naturally fluorescent cholesterol analog, dehydroergosterol (DHE), which has been shown to mimic many of the properties of cholesterol. By using DHE loaded on methyl-beta-cyclodextrin, we followed this cholesterol analog in pulse-chase studies. At steady state, DHE co-localizes extensively with transferrin (Tf), a marker for the endocytic recycling compartment (ERC), and redistributes with Tf in cells with altered ERC morphology. Expression of a dominant-negative mutation of an ERC-associated protein, mRme-1 (G429R), results in the slowing of both DHE and Tf receptor return to the cell surface. [3H]Cholesterol is found in the same fraction as 125I-Tf on sucrose density gradients, and this fraction can be specifically shifted to a higher density based on the presence of horseradish peroxidase-conjugated Tf in the same organelle. Whereas vesicular transport of Tf and efflux of DHE from the ERC are entirely blocked in energy-depleted cells, delivery of DHE to the ERC from the plasma membrane is only slightly affected. Biochemical studies performed using [3H]cholesterol show that the energy dependence of cholesterol transport to and from the ERC is similar to DHE transport. We propose that a large portion of intracellular cholesterol is localized in the ERC, and this pool might be important in maintaining cellular cholesterol homeostasis.

publication date

  • January 4, 2002

Research

keywords

  • Academic Article

Identity

Language

  • eng

Digital Object Identifier (DOI)

  • 10.1074/jbc.M108861200

PubMed ID

  • 11682487

Additional Document Info

start page

  • 609

end page

  • 17

volume

  • 277

number

  • 1