Protein phosphatase 1 regulatory subunit 3B (PPP1R3B)

Protein phosphatase 1 regulatory subunit 3B (PPP1R3B) is a regulatory subunit that targets the serine/threonine phosphatase PP1 specifically to glycogen particles in the liver and skeletal muscle[1][2][4][5]. By directing PP1 to its key substrates—glycogen synthase and glycogen phosphorylase—PPP1R3B stimulates glycogen synthesis and limits glycogen breakdown, thereby playing a critical role in maintaining glucose and energy homeostasis in response to nutritional and hormonal cues[2][4][5]. Genetic variants affecting PPP1R3B expression are associated with altered hepatic glucose and lipid storage, influencing the risk of metabolic diseases such as type 2 diabetes, hepatic steatosis, and hyperinsulinemic hypoglycemia[2][4]. PPP1R3B, expressed predominantly in liver, acts as a metabolic switch between glycogen and fat storage in hepatocytes, and its activity or dysregulation has been implicated in both rare and common metabolic disorders[4][6]. There are currently no approved drugs targeting PPP1R3B directly, but it remains of interest for its central metabolic regulatory role.

Other names

Protein phosphatase 1 regulatory subunit 4PP1 subunit R4GLG(L)PTGhepatic glycogen-targeting subunitFLJ14005hepatic glycogen-targeting protein phosphatase 1 regulatory subunit GLprotein phosphatase 1 regulatory (inhibitor) subunit 3BGL subunitPPP1R4