The team collected large-scale datasets of cellular biomolecules’ expression profiles upon Akt2-specific activation. They combined the data to get a unified view of the molecular networks regulated by Akt2. Credit: 2023 Kawamaru et al.
The hormone insulin is a central player in our body’s metabolic process of converting sugar (glucose) into energy, and dysfunction in the production or regulation of insulin is at the root of disorders such as diabetes. Insulin-regulated metabolic processes involve a series of molecular reactions mediated by enzymes known as kinases, and tracking the activity of individual kinases can be difficult due to the vast number of biomolecules and reactions involved in cellular metabolism. Researchers at the University of Tokyo School of Science have turned to optogenetics in order to better examine the role of the kinase Akt2 in insulin-regulated metabolism, using light to specifically activate the enzyme and identify signaling pathways that could have implications for the development of drugs for diabetes treatment.
The researchers performed their experiments on mouse skeletal muscle cells, in which the incorporation of light-sensitive Akt2 molecules enabled the enzyme to be selectively activated by light irradiation. Upon irradiation, the Akt2 molecules assemble at the cell membrane, and the molecules are deactivated when the light is turned off. By carefully controlling the activation of Akt2, the researchers could closely examine the kinase’s activity and better understand its role amidst the simultaneous activity of other biomolecules involved in insulin-regulated metabolism. The team paired their optogenetics method with transomics analysis, collecting large-scale data on the proteins, RNA transcripts and metabolites involved in the metabolics. Using this approach, the researchers were able to construct a map of the detailed molecular network triggered by Akt2 activation.
The data revealed that Akt2 uses different regulation mechanisms than insulin, with a regulated network that included 9 genes, 56 metabolic enzymes and 23 metabolites, compared with an insulin-regulated network of 32 genes, 43 metabolic enzymes and 18 metabolites. The researchers identified some metabolic reactions in which Akt2 acts alone, and others in which it acts with other enzymes; additionally, they found that Akt2 plays a crucial role in glycolysis and nucleotide metabolism. By revealing specific Akt2-dependent metabolic pathways, the research provides insights into Akt2 as a potential drug target for diabetes and other metabolic disorders. This study was published in Science Signaling.
“These results can contribute to elucidating the mechanisms of disease onset caused by mutations in Akt2 function,” said corresponding author Takeaki Ozawa. “They can also help the development of drugs targeting Akt2. The analytical framework used in this study is applicable to other biomolecules too. So, this approach is versatile to analyze the function of a specific enzyme inside a cell.”