Organization of the nicotinic acetylcholine receptor is affected by cytoskeleton-disrupting drugs

WENZ JORGE,; BARRANTES, FRANCISCO

San Miguel de Tucumán

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

SAIB

The cytoskeleton is assumed to participate in the protein clustering at cell surface, as the aggregation of AChR receptors at the neuromuscular junction. The effect of two cytoskeleton-disrupting drugs (cytochalasin D and jasplakinolide) on the organization of AChRs in CHO-K1/A5 cells was assessed by mathematical analysis of stimulated total emission depletion (STED) images. AChR clusters were found to be randomly distributed in control and treated samples at distances beyond 500 nm. For shorter distances (< than the prevailing diameter of clusters) no conclusion on the distribution could be reached owing to methodological restraints in the Ripley and Poisson analysis. However, drugs altered the arrangement of AChR nanoclusters, in a brightness-depending way. Drugs did not affect clusters brightness, but a significant increase in the proportion of the medium-size clusters and a diminution of the small-size ones was found in jasplakinolide-treated cells, suggesting a dispersive effect of AChR molecules within clusters. This dispersion was further corroborated by the diminution of the brightness/diameter ratio of clusters, and from Ripley´s analysis applied to patterns having simulated intra-clusters aggregation of AChR molecules. Taken together, our findings suggest that the cytoskeleton meshwork is involved in the anchoring and organization of the receptor at the cell surface.