Ceramides modulate cell-surface acetylcholine receptor levels

Biochim Biophys Acta. 2008 Apr;1778(4):917-30. doi: 10.1016/j.bbamem.2007.10.019. Epub 2007 Oct 30.

Abstract

The effects of ceramides (Cer) on the trafficking of the nicotinic acetylcholine receptor (AChR) to the plasma membrane were studied in CHO-K1/A5 cells, a clonal cell line that heterologously expresses the adult murine form of the receptor. When cells were incubated with short- (C6-Cer) or long- (brain-Cer) chain Cer at low concentrations, an increase in the number of cell-surface AChRs was observed concomitant with a decrease in intracellular receptor levels. The alteration in AChR distribution by low Cer treatment does not appear to be a general mechanism since the surface expression of the green fluorescent protein derivative of the vesicular stomatitis virus protein (VSVG-GFP) was not affected. High Cer concentrations caused the opposite effects, decreasing the number of cell-surface AChRs, which exhibited higher affinity for [125I]-alpha-bungarotoxin, and increasing the intracellular pool, which colocalized with trans-Golgi/TGN specific markers. The generation of endogenous Cer by sphingomyelinase treatment also decreased cell-surface AChR levels. These effects do not involve protein kinase C zeta or protein phosphatase 2A activation. Taken together, the results indicate that Cer modulate trafficking of AChRs to and stability at the cell surface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells
  • Cattle
  • Ceramides / pharmacology*
  • Cricetinae
  • Cricetulus
  • Endocytosis / drug effects
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / metabolism
  • Humans
  • Intracellular Space / drug effects
  • Intracellular Space / metabolism
  • Nystatin / pharmacology
  • Receptors, Nicotinic / metabolism*
  • Sphingomyelin Phosphodiesterase / pharmacology
  • Sphingosine / pharmacology

Substances

  • Ceramides
  • Receptors, Nicotinic
  • Nystatin
  • Sphingomyelin Phosphodiesterase
  • Sphingosine