FUS/TLS Stress Granules Assay from Innoprot requires a stable cell line expressing fluorescent FUS/TLS. During the assay, we incubate cells with test compounds and Sodium Arsenite to induce the FUS/TLS aggregation. Finally, we quantify fluorescent FUS/TLS nuclear globs using the BD Pathway HCS Reader and Attovision Compartimentalization Software.
Amyotrophic lateral sclerosis (ALS) is one of the most common degenerative diseases of the motor neuron system. FUS/TLS and TDP-43, two strikingly similar RNA Binding Proteins, are dominant causes of both the fatal adult motor neuron disease amyotrophic lateral sclerosis (ALS) and frontal temporal degeneration (FTD). Stress granules (SGs) are granules of RNA and proteins formed in the cytosol of the cell under stressful conditions. Disease-linked mutations of FUS increase its propensity to 
aggregate and to form SGs by preventing nuclear translocation.
In normal conditions, FUS/TLS protein is predominantly localized in the nucleus. In the presence of an oxidative insult like Sodium arsenite, FUS/TLS increases its cytoplasmic localization forming Stress granules. This assay measures both localization patterns to identify most promising test compounds.