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

Research output: Contribution to journalArticleScientificpeer-review

Details

Original languageEnglish
Number of pages16
JournalJournal of Cell Biology
DOIs
Publication statusPublished - 1 Nov 2019
Publication typeA1 Journal article-refereed

Abstract

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.

Publication forum classification

Field of science, Statistics Finland