Cholesterol modulates acetylcholine receptor organization and stability at the cell membrane

BAIER C.J.; KELLNER R; BORRONI V; WILLIG K.I; GARBUS I; HELL S.W; BARRANTES F.J

Cancun, México

Congreso; Int. Soc. for Neurochem. y 38th Annual Meeting of the Am. Soc. for Neurochem; 2007

International Society for neurochemistry-American Society for Neurochemistry

The effect of cholesterol (Chol) on acetylcholine receptor (AChR) supramolecular organization has been studied by a combination of approaches using the clonal cell line CHO-K1/A5, a mammalian cell line stably expressing adult murine AChR. Acute (30 min, 371C) exposure to methy-beta-cyclodextrin, commonly used as a diagnostic tool of endocytic mechanisms, dramatically accelerated AChR internalization from the cell surface. From a functional point of view, gain-of-function changes were observed in single-channel recordings upon Chol depletion. Wide-field and confocal microscopy disclosed AChR submicron-sized (240?280 nm) domains that remain stable over a period of hours at the cell membrane. Stimulated emission depletion (STED) fluorescence microscopy resolved the domains into AChR ??nanoclusters?? with a peak size distribution of B55 nm. Cyclodextrin-mediated Chol depletion resulted in a smaller number of nanoclusters with larger size, and changes in nanocluster distribution on larger scales (0.5?3.5microns). Chol content at the plasmalemma is postulated to modulate cell-surface organization and stability of receptor domains, and fine-tune receptor channel function to temporarily compensate for acute AChR loss from the cell-surface.