TBK1 and amyotrophic lateral sclerosis: OPTN's affinity for ubiquitin chains is enhanced by its phosphorylation, and TANK binding kinase 1 (TBK1), recently also found to be mutated in a subset of ALS patients (Cirulli et al., 2015), is a relevant kinase (Heo et al., 2015; Moore and Holzbaur, 2016; Richter et al., 2016).