Notes: These authors used a NanoBiT® complementation assay to investigate interactions between proteins implicated in development of amyotrophic lateral sclerosis (ALS). Mutations in superoxide dismutase 1 (SOD1) and in TAR‐binding protein 43 kDa (TDP43) have been associated with ALS. The authors observed formation of SOD1 homodimers in neuronal cells transfected with SOD1 tagged with NanoBiT complementation partners, and found that SOD1 mutants associated with ALS were unable to form homodimers.  Next, possible interactions between SOD1 and TDP43 were assessed. When NanoBiT-tagged constructs of TBP43 and SOD were transfected into Neuro 2A cells, only NanoBiT-tagged SOD generated a luciferase signal. TBP43 did not self-associate to form homodimers, and SOD1 and TBP43 did not interact with each other to form heterodimers. The authors state that NanoBiT is a useful and sensitive tool for analyzing protein interactions under physiological conditions, and may provide a convenient way to monitor the modulation of SOD1 conformation by candidate treatments. (4765)