5kqv
Insulin receptor ectodomain construct comprising domains L1,CR,L2, FnIII-1 and alphaCT peptide in complex with bovine insulin and FAB 83-14 (REVISED STRUCTURE)
Structural highlights
FunctionINS_BOVIN Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver. Publication Abstract from PubMedInsulin receptor signalling has a central role in mammalian biology, regulating cellular metabolism, growth, division, differentiation and survival. Insulin resistance contributes to the pathogenesis of type 2 diabetes mellitus and the onset of Alzheimer's disease; aberrant signalling occurs in diverse cancers, exacerbated by cross-talk with the homologous type 1 insulin-like growth factor receptor (IGF1R). Despite more than three decades of investigation, the three-dimensional structure of the insulin-insulin receptor complex has proved elusive, confounded by the complexity of producing the receptor protein. Here we present the first view, to our knowledge, of the interaction of insulin with its primary binding site on the insulin receptor, on the basis of four crystal structures of insulin bound to truncated insulin receptor constructs. The direct interaction of insulin with the first leucine-rich-repeat domain (L1) of insulin receptor is seen to be sparse, the hormone instead engaging the insulin receptor carboxy-terminal alpha-chain (alphaCT) segment, which is itself remodelled on the face of L1 upon insulin binding. Contact between insulin and L1 is restricted to insulin B-chain residues. The alphaCT segment displaces the B-chain C-terminal beta-strand away from the hormone core, revealing the mechanism of a long-proposed conformational switch in insulin upon receptor engagement. This mode of hormone-receptor recognition is novel within the broader family of receptor tyrosine kinases. We support these findings by photo-crosslinking data that place the suggested interactions into the context of the holoreceptor and by isothermal titration calorimetry data that dissect the hormone-insulin receptor interface. Together, our findings provide an explanation for a wealth of biochemical data from the insulin receptor and IGF1R systems relevant to the design of therapeutic insulin analogues. How insulin engages its primary binding site on the insulin receptor.,Menting JG, Whittaker J, Margetts MB, Whittaker LJ, Kong GK, Smith BJ, Watson CJ, Zakova L, Kletvikova E, Jiracek J, Chan SJ, Steiner DF, Dodson GG, Brzozowski AM, Weiss MA, Ward CW, Lawrence MC Nature. 2013 Jan 10;493(7431):241-5. doi: 10.1038/nature11781. PMID:23302862[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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