Chemical Interactions Involved in Insulin Receptor Activation: Scoping Review

This work overviews some complex molecular interactions and phosphorylation events in the insulin receptor (IR) signaling pathway and explains its central role in metabolic control, which starts from the synthesis and secretion of insulin by pancreatic β-cells under elevated blood glucose. The triggered pathway coordinates a cascade of molecular processes that results in the activation of primary metabolic functions. Insulin bound to its receptor starts a sequence of events, such as the autophosphorylation of the receptor β subunit for initiating downstream signaling cascades, glycogen synthesis, and the appropriate regulation of lipid metabolism. The complexity and specificity of the signaling pathway involve insulin receptor substrates, phosphatidylinositol-3-kinase (PI3K), and protein kinase B (PKB). A detailed molecular interaction analysis in the IR has pointed to the crucial role of some residues and structural elements necessary for enzymatic functionalities and substrate binding. These factors include the kinase domain of the IR with specific amino acid residues, and subsequent activation of downstream signaling proteins. The structural changes on phosphorylation promote the binding of SH2 domain-containing adaptor proteins, which lead to the initiation of multifunctional signaling complexes central to insulin signal transduction. These molecular mechanisms provide insight into pathophysiology relating to metabolic diseases and potential treatment targets. This review aims an understanding of insulin receptor operation, elucidating the molecular intricacies behind the eventful metabolic insulin signaling pathways and highlighting possible research and therapeutic development in the field of medicine.