Molecular basis for the role of disulfide-linked αCTs in the activation of insulin-like growth factor 1 receptor and insulin receptor

  1. Jie Li
  2. Jiayi Wu
  3. Catherine Hall
  4. Xiao-chen Bai  Is a corresponding author
  5. Eunhee Choi  Is a corresponding author
  1. The University of Texas Southwestern Medical Center, United States
  2. Columbia University, United States

Abstract

The insulin receptor (IR) and insulin-like growth factor 1 receptor (IGF1R) control metabolic homeostasis and cell growth and proliferation. The IR and IGF1R form similar disulfide bonds linked homodimers in the apo-state; however, their ligand binding properties and the structures in the active state differ substantially. It has been proposed that the disulfide-linked C-terminal segment of α-chain (αCTs) of the IR and IGF1R control the cooperativity of ligand binding and regulate the receptor activation. Nevertheless, the molecular basis for the roles of disulfide-linked αCTs in IR and IGF1R activation are still unclear. Here, we report the cryo-EM structures of full-length mouse IGF1R/IGF1 and IR/insulin complexes with modified αCTs that have increased flexibility. Unlike the Γ-shaped asymmetric IGF1R dimer with a single IGF1 bound, the IGF1R with the enhanced flexibility of αCTs can form a T-shaped symmetric dimer with two IGF1s bound. Meanwhile, the IR with non-covalently linked αCTs predominantly adopts an asymmetric conformation with four insulins bound, which is distinct from the T-shaped symmetric IR. Using cell-based experiments, we further showed that both IGF1R and IR with the modified αCTs cannot activate the downstream signaling potently. Collectively, our studies demonstrate that the certain structural rigidity of disulfide-linked αCTs is critical for optimal IR and IGF1R signaling activation.

Data availability

All cryo-EM maps and models reported in this work has been deposited into EMDB/PDB database under the entry ID: PDB-8EYR and EMD-28693 (IGF1R/IGF1, symmetric conformation), PDB-8EYX and EMD-28723 (IR-3CS/insulin, asymmetric conformation 1), PDB-8EYY and EMD-28724 (IR-3CS/insulin, asymmetric conformation 2), and PDB-8EZ0 and EMD-28725 (IR-3CS/insulin, symmetric conformation). Source data are provided with this paper.

The following data sets were generated

Article and author information

Author details

  1. Jie Li

    Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1059-280X
  2. Jiayi Wu

    Department of Pathology and Cell Biology, Columbia University, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9692-2864
  3. Catherine Hall

    Department of Pathology and Cell Biology, Columbia University, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Xiao-chen Bai

    Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, United States
    For correspondence
    Xiaochen.Bai@UTSouthwestern.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4234-5686
  5. Eunhee Choi

    Department of Pathology and Cell Biology, Columbia University, New York, United States
    For correspondence
    ec3477@cumc.columbia.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3286-6477

Funding

National Institute of General Medical Sciences (R35GM142937)

  • Eunhee Choi

National Institute of General Medical Sciences (R01GM136976)

  • Xiao-chen Bai

National Institute of Diabetes and Digestive and Kidney Diseases (1P30DK132710)

  • Eunhee Choi

Welch Foundation (I-1944)

  • Xiao-chen Bai

Cancer Prevention and Research Institute of Texas (RP160082)

  • Xiao-chen Bai

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

© 2022, Li et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 1,552
    views
  • 245
    downloads
  • 13
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Jie Li
  2. Jiayi Wu
  3. Catherine Hall
  4. Xiao-chen Bai
  5. Eunhee Choi
(2022)
Molecular basis for the role of disulfide-linked αCTs in the activation of insulin-like growth factor 1 receptor and insulin receptor
eLife 11:e81286.
https://doi.org/10.7554/eLife.81286

Share this article

https://doi.org/10.7554/eLife.81286

Further reading

    1. Cell Biology
    2. Medicine
    Shuo He, Lei Huang ... Jinlong He
    Research Article

    Disturbed shear stress-induced endothelial atherogenic responses are pivotal in the initiation and progression of atherosclerosis, contributing to the uneven distribution of atherosclerotic lesions. This study investigates the role of Aff3ir-ORF2, a novel nested gene variant, in disturbed flow-induced endothelial cell activation and atherosclerosis. We demonstrate that disturbed shear stress significantly reduces Aff3ir-ORF2 expression in athero-prone regions. Using three distinct mouse models with manipulated Aff3ir-ORF2 expression, we demonstrate that Aff3ir-ORF2 exerts potent anti-inflammatory and anti-atherosclerotic effects in Apoe-/- mice. RNA sequencing revealed that interferon regulatory factor 5 (Irf5), a key regulator of inflammatory processes, mediates inflammatory responses associated with Aff3ir-ORF2 deficiency. Aff3ir-ORF2 interacts with Irf5, promoting its retention in the cytoplasm, thereby inhibiting the Irf5-dependent inflammatory pathways. Notably, Irf5 knockdown in Aff3ir-ORF2 deficient mice almost completely rescues the aggravated atherosclerotic phenotype. Moreover, endothelial-specific Aff3ir-ORF2 supplementation using the CRISPR/Cas9 system significantly ameliorated endothelial activation and atherosclerosis. These findings elucidate a novel role for Aff3ir-ORF2 in mitigating endothelial inflammation and atherosclerosis by acting as an inhibitor of Irf5, highlighting its potential as a valuable therapeutic approach for treating atherosclerosis.

    1. Cell Biology
    2. Genetics and Genomics
    Róża K Przanowska, Yuechuan Chen ... Anindya Dutta
    Research Article

    The six-subunit ORC is essential for the initiation of DNA replication in eukaryotes. Cancer cell lines in culture can survive and replicate DNA replication after genetic inactivation of individual ORC subunits, ORC1, ORC2, or ORC5. In primary cells, ORC1 was dispensable in the mouse liver for endo-reduplication, but this could be explained by the ORC1 homolog, CDC6, substituting for ORC1 to restore functional ORC. Here, we have created mice with a conditional deletion of ORC2, which does not have a homolog. Although mouse embryo fibroblasts require ORC2 for proliferation, mouse hepatocytes synthesize DNA in cell culture and endo-reduplicate in vivo without ORC2. Mouse livers endo-reduplicate after simultaneous deletion of ORC1 and ORC2 both during normal development and after partial hepatectomy. Since endo-reduplication initiates DNA synthesis like normal S phase replication these results unequivocally indicate that primary cells, like cancer cell lines, can load MCM2-7 and initiate replication without ORC.