The deubiquitinase OTUB1 inhibits gluconeogenesis by stabilizing YWHAB.

Hepatic gluconeogenesis plays a crucial role in maintaining glucose homeostasis and serves as a potential therapeutic target for type 2 diabetes, while its underlying mechanisms are not fully understood. This study elucidates the role of the deubiquitinase OTU domain-containing ubiquitin aldehyde binding protein 1 (OTUB1) in gluconeogenesis. We found that hepatic OTUB1 expression is reduced in both db/db mice and patients with type 2 diabetes. Deletion of hepatic OTUB1 significantly elevates fasting blood glucose levels and increases the expression of key gluconeogenic genes. Conversely, overexpression of OTUB1 in hepatocytes mitigates diabetic hyperglycemia and enhances insulin sensitivity. It is known that the tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein β (YWHAB) functions as an inhibitor of hepatic gluconeogenesis by interacting with forkhead box protein O (FOXO1) and glucagon receptor (GPCR), but its own modification mechanism remains unclear. Our findings indicate that OTUB1 interacts with YWHAB and deubiquitinates it through a catalytic process, which in turn suppresses gluconeogenesis. Therefore, OTUB1 plays a pivotal role in inhibiting hepatic gluconeogenesis, highlighting its potential as a therapeutic target for type 2 diabetes.