AChR distribution after ceramide treatment of Cho-k1/a5 cells

PEDICONI M.; GALLEGOS C.; DE LOS SANTOS E.; CUTINI P.; BARRANTES F.J.

Congreso; ARGENTINE SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY XXXIX ANNUAL MEETING. BIOPHYSICAL SOCIETY OF ARGENTINA XXXII ANNUAL MEETING. BARILOCHE PROTEIN SYMPOSIUM; 2003

With the aim to study the mechanisms involved in the regulation of acetylcholine receptor (AChR) targeting to the plasma membrane, we studied the effect promoted by short (C6)- or long brain ceramides on AChR expression, metabolism, and cellular distribution. C6-Cer reduced by 30-80% the amount of [125 I]alpha-BTX AChR detected at the cell surface of CHO-K1/A5 cells. This decrease was a dose- and time-dependent effect, augmenting also the ligand affinity for [125I] alpha-BTX. The half-life of surface AChR was 5.7 and 8.3 h for control and treated cells, respectively. C6-Cer produced intracellular accumulation of AChR (72±15% vs. 49±3 in control cells) without apparent cell damage. Fluorescence microscopy using Alexa594 alpha-BTX labeling showed that brain-Cer and C6-cer decreased the amount of AChR localized at the plasmalemma. Whereas C6-Cer induced intracellular AChR accumulation in a vesicle-like compartment, brain Cer increased the amount of intracellular AChR with a more homogeneous distribution.