PLIN5 and Wilson disease: Interestingly, when we analyzed the common upstream regulator of CPT1 and PGC-1α, AMPK, Plin5−/− mice tended to present lower levels of phosphorylated AMPK (pAMPK) than control mice, possibly indicating that mitochondrial function is impaired in Plin5−/− mice fed with WD (Fig. 3F).