Cluster size-depending effect of cytoskeleton-disrupting drugs on acetylcholine receptor organization.

WENZ J.J.; BARRANTES F.J.

Puerto Madryn

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

SAIB

The study of protein clustering in cell membranes may be constrained when the size of the agglometares is bellow the resolution of the microscopy used. Classical pattern tests (Ripley, Poisson) make use only of the (x,y) coordinates of spots, and unsolved clusters are then judged as a single and dimensionless points. Cluster size/brightness is not considered by these methods either and their outputs may well lead to misleading interpretations. We present here a procedure to analyze images that account for the size of clusters, ongoing our work (SAIB 2009) aimed to establish whether the membrane organization of the nicotinic acetylcholine receptor (AChR) is linked to cytoskeleton integrity. The analysis is based on the frequency distribution of euclidean distances calculated from three-dimensional coordinates [e.g., x,y,brightness] between all pairs of spots in stimulated total emission depletion (STED) images. Next, the frequency distributions from control and cytochalasin D and jasplakinolide treated CHO-K1/A5 cells were contrasted with simulated random and nonrandom patterns having similar numbers of spots. Comparisson of the frequency distributions of the euclidean distances indicates that treatments with the cytoskeleton-disrupting drugs affect the receptor aggregation at cell surface and that such effect is related to the size/brightness of the agglomerates.