FUS and amyotrophic lateral sclerosis: Second, although the differently phosphorylated FUS residue (pS439) is not a site that is known to be mutated in ALS patients, pS439 is located in the zinc finger domain of FUS (Fig 6A) which is known to be involved in recognition and binding of RNA targets (Nguyen et al, 2011;Loughlin &, Wilce, 2019; Loughlin et al, 2019).