MEDAG functions as an A-kinase-anchoring protein in adipocytes

Induction of catabolic adipocyte activity independent of mitochondrial uncoupling to induce energy expenditure has received increasing attention. In this study, we identified mesenteric estrogen-dependent adipogenesis gene (MEDAG), a poorly studied gene, as a promising therapeutic target for enhancing energy expenditure in adipocytes. We demonstrated that adipose MEDAG expression positively correlates with obesity and metabolic dysfunction in humans. Consistently, adipocyte-specific ablation of Medag in mice leads to increased energy expenditure, offering protection from diet-induced obesity. Mechanistically, we show that MEDAG functions as an A-kinase-anchoring protein (AKAP), which can directly regulate protein kinase A (PKA) activity through a negative feedback loop, involving direct interaction with PKA leading to MEDAG phosphorylation and consequent feedback fine-tuning of PKA activity. Specifically, the direct interaction of MEDAG with the PKA-RIIβ subunit regulates the stability of PKA-RIIβ to prevent PKA hyperactivation. These findings position MEDAG as a target for adipose energy expenditure and uncover its AKAP activity.