Diacylglicerides affect distribution and binding properties of the nicotinic acetylcholine receptor

KAMERBEEK, C.B.; VALLÉS, A.S.; PEDICONI, M.F.; BARRANTES, F.J.

Puerto Madryn

Congreso; XLVI Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2010

Sociedad Argentina de Investigación en Bioquímica y Biología

The effects of exogenous and endogenously-generated diacylglycerides (DAG) on the density, affinity, distribution and single-channel properties of the nicotinic acetylcholine receptor (AChR) in CHO-K1/A5 cells were evaluated by a combination of techniques. [125I]-alfa-bungarotoxin ligand binding assays showed that cells incubated in the presence of palmitoyloleoylglycerol and dioctanoylglycerol (DOG) for 30 min to 3 h augmented cell-surface AChR levels, with a concomitant decrease in the affinity for thetoxin. Longer exposures (18-48 h) decreased AChR density to values between 60 and 80% of those found in control cells. The remaining AChRs accumulated at intracellular compartments. Electrophysiological studies revealed that DOG treatment (30 min) decreased the mean open time of the AChR channel. Increasing the intracellular DAG pool with the diacylglycerol kinase inhibitor R59949, alone or applied together with DOG, promoted a 50 and 100% increase of the cell-surface AChR, respectively. In the latter case, a 50% decrease in the intracellular pool of the receptor was also observed. We conclude that exogenous and endogenous DAGs modulate the expression, distribution and single-channel properties of the muscle-type AChR.