title: Prediction of a novel internal rearrangement of the insulin receptor.
abstract: The insulin receptor (IR) plays critical roles in metabolism and growth, directed by the binding of insulin. Decades of research to understand the mechanism of insulin binding and activation of the IR have identified a region of the receptor, the C-terminal (CT) peptide, to be crucial for insulin binding. In particular, a truncated IR consisting of the first three domains fused to the CT peptide was found to bind insulin with nanomolar affinity, with undetectable binding in the absence of fused or soluble CT peptide. Problematically, all current crystal structures of the IR indicate the fusion point of the CT peptide to the three domains is located far from the position of the CT peptide as resolved in such structures. We have attempted to address this problem using molecular modelling and dynamics simulations. The results led to the identification of a potential inter-domain interaction between the L2 domain and the CT peptide that is not observed in any of the crystal structures of the IR. Investigations into this new interaction found a conformational change that could potentially be in response to insulin binding. Additionally, further simulation work with the new conformation demonstrated its compatibility with the position and orientation of insulin from the latest insulin-bound IR crystal structure.
authors.affiliation: a Institute of Health and Biomedical Innovation , Queensland University of Technology , Brisbane , Australia.
authors.forename: Kei C
authors.initials: KC
authors.lastname: Sit
authors.affiliation: a Institute of Health and Biomedical Innovation , Queensland University of Technology , Brisbane , Australia.
authors.forename: Derek
authors.initials: D
authors.lastname: van Lonkhuyzen
authors.affiliation: b Faculty of Health, School of Biomedical Science , Institute of Health and Biomedical Innovation, Queensland University of Technology , Brisbane , QLD , Australia.
authors.forename: Terry
authors.initials: T
authors.lastname: Walsh
authors.affiliation: a Institute of Health and Biomedical Innovation , Queensland University of Technology , Brisbane , Australia.|b Faculty of Health, School of Biomedical Science , Institute of Health and Biomedical Innovation, Queensland University of Technology , Brisbane , QLD , Australia.
authors.forename: Tristan
authors.initials: T
authors.lastname: Croll
mesh_terms: D015703:Antigens, CD / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D006801:Humans; D007328:Insulin / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D010766:Phosphorylation; D011487:Protein Conformation; D011972:Receptor, Insulin / Q000737:chemistry* / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D007328:Insulin; D010446:Peptide Fragments; C435941:INSR protein, human; D011972:Receptor, Insulin
keywords: conformational change; insulin receptor; inter-domain interactions; molecular dynamics simulations; molecular modelling; principal components analysis