Evaluation of assay performance.

ß-dystroglycan clustering is a suitable assay for detection using the Cellomics™ Arrayscan VTI automated fluorescence imager. ß-DG clustering in laminin-treated astrocytes was used as the positive control and the spontaneous clustering occurring in the absence of exogenous laminin was used as the negative control. Z′ = 1−((3σmax+3σmin)/|μmax−μmin|), where μmax is the mean positive control signal, σmax is the standard deviation of the positive control signal, μmin is the mean negative control signal, and σmin is the standard deviation of the negative control signal. Signal/background (fold increase) = μmax/μmin. Signal/noise = (μmax−μmin)/σmin. Signal window = (μmax−μmin−3(σmax+σmin))/σmax[34].