User:Yousif Saleh/sandbox

Protein-Ligand complex is essential in many of the cellular processes that occur within organisms. One of these examples is the Glucagon receptor (GCGR). Glucagon receptor (GCGR) is a family of G-protein coupled receptors (GPCRs) in humans that plays an important role in maintaining glucose concentration within the blood during periods of low energy state. Glucagon binding to GPCR causes a conformational change in the intracellular domain, allowing interaction with the heterotrimeric Gs protein. The alpha Subunit of the Gs protein releases bound GDP and binds GTP. The alpha subunit-GTP complex dissociates from the beta and gamma dimer and interacts with adenylate cyclase. Binding of glucagon molecule activates many of the alpha subunit, which amplifies the hormonal signal. Then, the alpha subunit activates the adenylate cyclase, which converts ATP to cAMP. The alpha subunit deactivates itself within minutes by hydrolyzing GTP to GDP (GTPase activity). The alpha subunit reassociates with beta-gamma dimer to form an inactive complex. A better understanding of the protein-ligand complex mechanisms may allow us for the treatment of some diseases such as type 2 diabetes. Glucagon receptor inhibitors are promising for the treatment of type 2 diabetes. Inhibitors of Glucagon receptors are either glucagon neutralizers or small molecular antagonists, and they all rely on the concept of protein-ligand complex interaction.