scholarly journals Structural basis by which a recessive mutation in the alpha-subunit of the insulin receptor affects insulin binding.

1994 ◽  
Vol 269 (21) ◽  
pp. 14912-14918
Author(s):  
M. Taouis ◽  
R. Levy-Toledano ◽  
P. Roach ◽  
S.I. Taylor ◽  
P. Gorden
Keyword(s):  
Insulin Receptor ◽  
Insulin Binding ◽  
Alpha Subunit ◽  
Structural Basis ◽  
Recessive Mutation

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

2019 ◽  
Author(s):  
Theresia Gutmann ◽  
Ingmar Schäfer ◽  
Chetan Poojari ◽  
Beate Brankatschk ◽  
Ilpo Vattulainen ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Binding Sites ◽  
Structural Model ◽  
Receptor Site ◽  
Insulin Binding ◽  
Proximal Region ◽  
Dynamics Simulation ◽  
Structural Basis ◽  
Structure Based Drug Design ◽  
Receptor Interactions

AbstractGlucose 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.

Insulin Receptor: 3D Reconstruction from Darkfield Stem Images, Structural Interpretation and Functional Model

1999 ◽  
Vol 5 (S2) ◽  
pp. 408-409
Author(s):  
F.P. Ottensmeyer ◽  
R.Z.-T. Luo ◽  
A.B. Fernandes ◽  
D. Benia ◽  
C.C. Yip
Keyword(s):  
Growth Factor ◽  
Insulin Receptor ◽  
Tyrosine Kinases ◽  
Quaternary Structure ◽  
Functional Model ◽  
Growth Factor Receptor ◽  
Insulin Binding ◽  
Dark Field ◽  
Bovine Insulin ◽  
Structural Basis

We have reconstructed the three-dimensional quaternary structure of the complete 480 kDa insulin receptor (IR), complexed with NanoGold-labelled insulin, via sets of electron micrographs obtained by low-dose low-temperature dark field scanning transmission electron microscopy (STEM).Insulin binding to IR in mammalian cell membranes is essential for its manifold effects such as glucose homeostasis, increased protein synthesis, growth, and development. IR belongs to the superfamily of transmembrane receptor tyrosine kinases that include the monomeric epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor (PDGFR). In contrast, IR and its homologues IGF-1R (insulin-like growth factor 1 receptor) and IRR (insulin receptorrelated receptor) are sub-types of this family that are intrinsic disulfide-linked dimers of two αβ heterodimers. Monomeric receptor TKs are inactive, but are activated by ligand-induced dimerization that results in autophosphorylation. IR-like TKs are also inactive even though they are already dimeric, and are activated by ligand binding without further oligomerization. Insulin binding to the extracellular domain of IR results in autophosphorylation of specific tyrosines to initiate an intracellular signal transduction cascade. However, because the quaternary structure of IR is not known, the structural basis for the mechanism of IR activation by extracellular insulin binding has not been elucidated.The insulin receptor was purified from human placenta. Bovine insulin was derivatized with NanoGold at the B chain Phel, a location not directly involved in receptor binding. Binding of derivatized insulin to the purified receptor was reduced only slightly compared to binding of the native insulin.

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

2019 ◽  
Vol 219 (1) ◽  
Author(s):  
Theresia Gutmann ◽  
Ingmar B. Schäfer ◽  
Chetan Poojari ◽  
Beate Brankatschk ◽  
Ilpo Vattulainen ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Binding Sites ◽  
Receptor Site ◽  
Insulin Binding ◽  
Dynamics Simulation ◽  
Structural Basis ◽  
Combined Approach ◽  
Comprehensive Description ◽  
Structure Based Drug Design ◽  
Receptor Interactions

Glucose homeostasis and growth essentially depend on the 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 resolved only site 1. Using a combined approach of cryo-EM and atomistic molecular dynamics simulation, we present 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 for a comprehensive description of ligand–receptor interactions that ultimately will inform new approaches to structure-based drug design.

scholarly journals Insulin-like and insulin-inhibitory effects of monoclonal antibodies for different epitopes on the human insulin receptor

1987 ◽  
Vol 242 (1) ◽  
pp. 123-129 ◽  
Author(s):  
R Taylor ◽  
M A Soos ◽  
A Wells ◽  
M Argyraki ◽  
K Siddle
Keyword(s):  
Monoclonal Antibodies ◽  
Insulin Receptor ◽  
Human Insulin ◽  
Insulin Binding ◽  
Metabolic Effects ◽  
Alpha Subunit ◽  
Inhibitory Effects ◽  
Molar Basis ◽  
Human Insulin Receptor ◽  
Receptor Beta

Monoclonal antibodies previously shown to react with five distinct epitopes on the human insulin receptor were tested for their metabolic effects on isolated human adipocytes. Two antibodies which reacted with receptor alpha-subunit and completely inhibited 125I-insulin binding mimicked the actions of insulin to stimulate lipogenesis from [14C]glucose and to inhibit catecholamine-induced lipolysis. On a molar basis, these antibodies were comparable in potency with insulin itself. Two other antibodies which decreased insulin binding only slightly or not at all also mimicked these metabolic effects of insulin. One of these antibodies reacted with receptor beta-subunit. In contrast, a further antibody which reacted with alpha-subunit and inhibited insulin binding did not affect basal lipogenesis or catecholamine-induced lipolysis, but was able to antagonize the effects of insulin on these processes. The same antibody antagonized the insulin-like effect of another antibody with which it competed in binding to insulin receptor, but not the effect of an antibody which bound independently to the receptor. It is concluded that binding of ligand at or close to the insulin-binding site is neither necessary nor sufficient to trigger insulin-like metabolic effects, which may rather depend on some general property of antibodies, such as their ability to cross-link and aggregate receptor molecules.

scholarly journals Changes in insulin-receptor structure associated with trypsin-induced activation of the receptor tyrosine kinase

1991 ◽  
Vol 276 (1) ◽  
pp. 27-33 ◽  
Author(s):  
S Clark ◽  
G Eckardt ◽  
K Siddle ◽  
L C Harrison
Keyword(s):  
Tyrosine Kinase ◽  
Insulin Receptor ◽  
Receptor Tyrosine Kinase ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Alpha Subunit ◽  
Beta Subunits ◽  
Receptor Kinase ◽  
Trypsin Treatment ◽  
Receptor Structure

The tyrosine kinase of the insulin receptor can be activated by trypsin treatment. The concomitant abolition of insulin binding has been postulated to result from proteolytic destruction of the receptor. A discrepancy between the decrease in insulin binding and receptor immunoreactivity after trypsin treatment led us to investigate more closely the structure of the trypsin-treated receptor. After trypsin treatment of the CHOT cell line, which over-expresses transfected human insulin receptors, insulin binding was significantly decreased, but reactivity with five alpha-subunit monoclonal antibodies was either unaffected or only moderately decreased, indicating that the alpha-subunit was substantially intact. Examination of receptor structure after trypsin treatment, receptor autophosphorylation and gel electrophoresis revealed a single band at 110 kDa in non-reduced gels, comprising a small fragment (21 kDa) of the alpha-subunit linked to the beta-subunit by class II disulphides. When the receptor was radio-labelled with 125I, two additional alpha-subunit bands of 142 kDa and 81 kDa (composed of identical reduced bands) were observed on non-reduced gels, which contained disulphide-linked (class I) fragments. All fragments could be precipitated by antibodies to both alpha- and beta-subunits. However, only antibodies directed towards the N-terminus of the receptor could immunoblot trypsin-treated fragments. Thus activation of the receptor tyrosine kinase by trypsin occurs after cleavage, but not loss of the alpha-subunit. This finding has implications for the mechanism of transmembrane activation of the receptor kinase by insulin.

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