USP7 and sleep disorder: USP7 itself is negatively regulated by MAGEL2, an E3 ligase mentioned above which is highly expressed in the SCN and associated with sleep disorders and circadian rhythm disruptions in both humans and mice (Carias et al., 2020; Kozlov et al., 2007; Lee et al., 2003), suggesting that USP7 may influence mammalian sleep–wake regulation as part of a broader transcriptional complex.