In hepatocytes, ATP7B deficiency in the trans-Golgi network (TGN) leads to abnormalities in mitochondrial function and copper metabolism, and ultimately to a wide range of liver diseases (Figure 1b; Członkowska et al., 2018; Roberts et al., 2008; Zischka and Lichtmannegger, 2014; Muchenditsi et al., 2021). Here, ATP7B is linked to liver disorder.