PPP1R3B encodes a regulatory subunit that targets protein phosphatase 1 (PP1) to glycogen, serving as a critical regulator of hepatic glycogen metabolism and energy homeostasis 1. The protein facilitates PP1's interaction with glycogen metabolic enzymes, enhancing glycogen synthase activation while suppressing glycogen phosphorylase activity, thereby promoting glycogen synthesis over breakdown 1. mTORC1 controls postprandial hepatic glycogen synthesis by promoting feeding-dependent induction of PPP1R3B through FOXO1-mediated transcriptional regulation 1. Genetic variants affecting PPP1R3B expression have broad metabolic implications: increased expression is associated with lower liver fat and decreased plasma lipids, while loss-of-function variants correlate with increased liver fat and elevated plasma lipids 2. PPP1R3B variants influence whether hepatic energy is stored as glycogen or triglycerides, with the protein serving as a crucial metabolic switch beyond glycogen synthesis 2. Genome-wide association studies have identified PPP1R3B variants associated with blood lipid levels and cardiovascular disease risk 34. The gene shows pregnancy-specific effects on glucose homeostasis, with variants demonstrating greater influence during pregnancy compared to postpartum periods 5. Additionally, PPP1R3B promotes anti-inflammatory M2 macrophage polarization through glycogen metabolic reprogramming, potentially suppressing atherosclerosis progression 6.