We used Lys63-linkage-specific antibodies instead of ubiquitin in this experiment for the following two reasons: i) ubiquitin antibody cross-reacts with free ISG15 [8]; and ii) presence of the Lys63-linked polyubiquitylated proteins in the inclusion bodies/aggregates has been documented in various neurological disorders (Paine et al., 2008). The gene discussed is ISG15; the disease is nervous system disorder.