Structural Perspectives of Insulin Receptor Isoform-Selective Insulin Analogs

Jiráček, Jiřı́; Žáková, Lenka

doi:10.3389/fendo.2017.00167

Cited by 23 publications

(27 citation statements)

References 49 publications

(73 reference statements)

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“…Although insulin replacement remains an essential therapy, it is still hampered by the inability of exogenously administered insulins to recapitulate the full spectrum of physiological insulin action (Jiracek and Zakova, 2017). A thorough understanding of the molecular details of ligand-insulin receptor activation is prerequisite for the development of specific agonists as well as antagonists.…”

Section: What Is the Role Of The Interaction Of Insulin With Sites 2 mentioning

confidence: 99%

Cryo-EM structure of the complete and ligand-saturated insulin receptor ectodomain

Gutmann

Schäfer

Poojari³

et al. 2019

Preprint

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Glucose homeostasis and growth essentially depend on the peptide hormone insulin engaging its receptor. Despite biochemical and structural advances, a fundamental contradiction has persisted in the current understanding of insulin ligand-receptor interactions. While biochemistry predicts two distinct insulin binding sites, 1 and 2, recent structural analyses have only resolved site 1.Using a combined approach of cryo-EM and atomistic molecular dynamics simulation, we determined the structure of the entire dimeric insulin receptor ectodomain saturated with four insulin molecules. Complementing the previously described insulin-site 1 interaction, we present the first view of insulin bound to the discrete insulin receptor site 2. Insulin binding stabilizes the receptor ectodomain in a T-shaped conformation wherein the membrane-proximal domains converge and contact each other. These findings expand the current models of insulin binding to its receptor and of its regulation. In summary, we provide the structural basis enabling a comprehensive description of ligand-receptor interactions that ultimately will inform new approaches to structure-based drug design. In briefA cryo-EM structure of the complete insulin receptor ectodomain saturated with four insulin ligands is reported. The structural model of the insulin-insulin receptor complex adopts a T-shaped conformation, reveals two additional insulin-binding sites potentially involved in the initial interaction of insulin with its receptor, and resolves the membrane proximal region.

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Section: What Is the Role Of The Interaction Of Insulin With Sites 2 mentioning

confidence: 99%

Cryo-EM structure of the complete and ligand-saturated insulin receptor ectodomain

Gutmann

Schäfer

Poojari³

et al. 2019

Preprint

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show abstract

“…Moreover, IR-A, IR-B, and IGF-1R can form what are known as hybrid receptors, composed of one pair of αβ subunits from one receptor and the second αβ pair from another receptor (6). The IR-A, IR-B, and IGF-1R receptors have different tissue distributions and can bind individual hormones with different affinities (7). Furthermore, the availability of IGFs is modulated by a family of six IGF-binding proteins (8), and IGF-2 also binds to a distinct receptor for IGF-2 (9, 10).…”

Section: Introductionmentioning

confidence: 99%

Mutations at hypothetical binding site 2 in insulin and insulin-like growth factors 1 and 2 result in receptor- and hormone-specific responses

Macháčková

Mlčochová

Potalitsyn

et al. 2019

Journal of Biological Chemistry

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Information on how insulin and insulin-like growth factors 1 and 2 (IGF-1 and -2) activate insulin receptors (IR-A and -B) and the IGF-1 receptor (IGF-1R) is crucial for understanding the difference in the biological activities of these peptide hormones. Cryo-EM studies have revealed that insulin uses its binding sites 1 and 2 to interact with IR-A and have identified several critical residues in binding site 2. However, mutagenesis studies suggest that Ile-A10, Ser-A12, Leu-A13, and Glu-A17 also belong to insulin's site 2. Here, to resolve this discrepancy, we mutated these insulin residues and the equivalent residues in IGFs. Our findings revealed that equivalent mutations in the hormones can result in differential biological effects and that these effects can be receptor-specific. We noted that the insulin positions A10 and A17 are important for its binding to IR-A and IR-B and IGF-1R and that A13 is important only for IR-A and IR-B binding. The IGF-1/IGF-2 positions 51/50 and 54/53 did not appear to play critical roles in receptor binding, but mutations at IGF-1 position 58 and IGF-2 position 57 affected the binding. We propose that IGF-1 Glu-58 interacts with IGF-1R Arg-704 and belongs to IGF-1 site 1, a finding supported by the NMR structure of the less active Asp-58–IGF-1 variant. Computational analyses indicated that the aforementioned mutations can affect internal insulin dynamics and inhibit adoption of a receptor-bound conformation, important for binding to receptor site 1. We provide a molecular model and alternative hypotheses for how the mutated insulin residues affect activity.

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“…Such different affinities may be due to different experimental setups and most probably because of different kinds of receptor protein or its immobilization. Indeed, binding studies with native insulin receptors in intact cells [68] or in isolated cell membranes [69,70] determined much higher affinities (~0.2-0.5 nM and~0.5-1 nM, respectively) than the binding affinities determined by SPR (73 nM and 166 nM) [71].…”

Section: D11 Of Igf2r Igf1r Ir-mentioning

confidence: 93%

A radioligand binding assay for the insulin-like growth factor 2 receptor

et al. 2020

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Insulin-like growth factors 2 and 1 (IGF2 and IGF1) and insulin are closely related hormones that are responsible for the regulation of metabolic homeostasis, development and growth of the organism. Physiological functions of insulin and IGF1 are relatively well-studied, but information about the role of IGF2 in the body is still sparse. Recent discoveries called attention to emerging functions of IGF2 in the brain, where it could be involved in processes of learning and memory consolidation. It was also proposed that these functions could be mediated by the receptor for IGF2 (IGF2R). Nevertheless, little is known about the mechanism of signal transduction through this receptor. Here we produced His-tagged domain 11 (D11), an IGF2-binding element of IGF2R; we immobilized it on the solid support through a well-defined sandwich, consisting of neutravidin, biotin and synthetic anti-His-tag antibodies. Next, we prepared specifically radiolabeled [ 125 I]-monoiodotyrosyl-Tyr2-IGF2 and optimized a sensitive and robust competitive radioligand binding assay for determination of the nanomolar binding affinities of hormones for D11 of IGF2. The assay will be helpful for the characterization of new IGF2 mutants to study the functions of IGF2R and the development of new compounds for the treatment of neurological disorders.

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Structural Perspectives of Insulin Receptor Isoform-Selective Insulin Analogs

Cited by 23 publications

References 49 publications

Cryo-EM structure of the complete and ligand-saturated insulin receptor ectodomain

Cryo-EM structure of the complete and ligand-saturated insulin receptor ectodomain

Mutations at hypothetical binding site 2 in insulin and insulin-like growth factors 1 and 2 result in receptor- and hormone-specific responses

A radioligand binding assay for the insulin-like growth factor 2 receptor

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