PAK4 and fatty liver disease: Furthermore, serum and hepatic triglyceride (TG) levels, gross liver morphology, and histochemical analysis (H&E and Oil Red O staining) demonstrated that liver steatosis induced by fasting or KD-feeding was exacerbated by PAK4 overexpression, but not PAKS474A (Fig. 2b–d and Supplementary Fig. 3c).