Harnessing Structural Data of Insulin and Insulin Receptor for Therapeutic Designs

Abstract

To lower blood glucose concentration, insulin binds to insulin receptor (IR) that possesses two distinct insulin binding sites to trigger downstream signaling events leading to an increased uptake of glucose into muscle and fat cells. Comprehensive understandings of structural and dynamic mechanisms of insulin and its receptor are essential to design therapeutic agents for treating and delaying the onset of diabetes that affects over 347 million people worldwide. No full-length IR structure is available hitherto. Harnessing the currently available and state-of-the-art sequence and structural data, we have reviewed the insulin, IR, its extracellular domains and transmembrane domain, to derive structure-based clues to regulate aberrant insulin and its receptor. To propose testable hypotheses and future experiments, we have performed literature review, text mining, multiple structural clustering and normal mode analysis on insulin and its receptor. It appears that insulin-receptor interaction involves allostery and conformational changes (including rotation and tilting) to overcome steric clashes. To target a particular aberrant isoform of IRs, we need to identify the subtle yet distinct differences between IR isoforms. To improve the life quality of diabetics, better structure-based designs of insulin mimetics, formulation and nanotechnology-based delivery are required; efforts to bring them to patients necessitate thorough structural understandings of insulin and its receptor. J Endocrinol Metab. 2015;5(5):273-283 doi: http://dx.doi.org/10.14740/jem302w