1
|
Lee J, Miyazaki M, Romeo GR, Shoelson SE. Insulin receptor activation with transmembrane domain ligands. J Biol Chem 2014; 289:19769-77. [PMID: 24867955 DOI: 10.1074/jbc.m114.578641] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Complementary surfaces are buried when peptide hormones, growth factors, or cytokines bind and activate cellular receptors. Although these extended surfaces provide high affinity and specificity to the interactions, they also present great challenges to the design of small molecules that might either mimic or antagonize the process. We show that the insulin receptor (IR) and downstream signals can be activated by targeting a site outside of its ligand-binding domain. A 24-residue peptide having the IR transmembrane (TM) domain sequence activates IR, but not related growth factor receptors, through specific interactions with the receptor TM domain. Like insulin-dependent activation, IR-TM requires that IR have a competent ATP-binding site and kinase activation loop. IR-TM also activates mutated receptors from patients with severe insulin resistance, which do not respond to insulin. These results show that IR can be activated through a pathway that bypasses its canonical ligand-binding domain.
Collapse
Affiliation(s)
- Jongsoon Lee
- From the Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215
| | - Masaya Miyazaki
- From the Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215
| | - Giulio R Romeo
- From the Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215
| | - Steven E Shoelson
- From the Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215
| |
Collapse
|
2
|
Kristensen C, Andersen AS, Ostergaard S, Hansen PH, Brandt J. Functional reconstitution of insulin receptor binding site from non-binding receptor fragments. J Biol Chem 2002; 277:18340-5. [PMID: 11901156 DOI: 10.1074/jbc.m112249200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that a minimized insulin receptor (IR) consisting of the first 468 amino acids of the insulin receptor fused to 16 amino acids from the C terminus of the alpha-subunit (CT domain) bound insulin with nanomolar affinity (Kristensen, C., Wiberg, F. C., Schäffer, L., and Andersen, A. S. (1998) J. Biol. Chem. 273, 17780-17786). In the present study, we show that a smaller construct that has the first 308 residues fused to the CT domain also binds insulin. Insulin receptor fragments consisting of the first 468 or 308 residues did not bind insulin. However, when these fragments were mixed with a synthetic peptide corresponding to the CT domain, insulin binding was detectable. At concentrations of 10 microm CT peptide, insulin binding was fully reconstituted yielding apparent affinities of 9-11 nm. To further investigate the minimum requirement for the length of the N terminus of IR, we tested smaller receptor fragments for insulin binding in the presence of the CT peptide and found that a fragment consisting of the first 255 amino acids of IR was able to fully reconstitute the insulin binding site, yielding an apparent affinity of 11 +/- 4 nm for insulin.
Collapse
Affiliation(s)
- Claus Kristensen
- Departments of Protein Expression and Insulin Research, Novo Nordisk A/S, 2880 Bagsvaerd, Denmark
| | | | | | | | | |
Collapse
|
3
|
Kristensen C, Wiberg FC, Andersen AS. Specificity of insulin and insulin-like growth factor I receptors investigated using chimeric mini-receptors. Role of C-terminal of receptor alpha subunit. J Biol Chem 1999; 274:37351-6. [PMID: 10601304 DOI: 10.1074/jbc.274.52.37351] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have investigated the role of the C-terminal of the alpha-subunit in the insulin receptor family by characterizing chimeric mini-receptor constructs comprising the first three domains (468 amino acids) of insulin receptor (IR) or insulin-like growth factor I receptor (IGFIR) combined with C-terminal domain from either insulin receptor (IR) (residues 704-719), IGFIR, or insulin receptor-related receptor (IRRR). The constructs were stably expressed in baby hamster kidney cells and purified, and binding affinities were determined for insulin, IGFI, and a single chain insulin/IGFI hybrid. The C-terminal domain of IRRR was found to abolish binding in IR and IGFIR context, whereas other constructs bound ligands. The two constructs with first three domains of the IR demonstrated low specificity for ligands, all affinities ranging from 3.0 to 15 nM. In contrast, the constructs with the first three domains of the IGFIR had high specificity, the affinity of the novel minimized IGFIR for IGFI was 1.5 nM, whereas the affinity for insulin was more than 3000 nM. When swapping the C-terminal domains in either receptor context only minor changes were observed in affinities (<3-fold), demonstrating that the carboxyl-terminal of IR and IGFIR alpha-subunits are interchangeable and suggesting that this domain is part of the common binding site.
Collapse
Affiliation(s)
- C Kristensen
- Insulin Research, Health Care Discovery, Novo Nordisk, 2880 Bagsvaerd, Denmark.
| | | | | |
Collapse
|
4
|
Kristensen C, Wiberg FC, Schäffer L, Andersen AS. Expression and characterization of a 70-kDa fragment of the insulin receptor that binds insulin. Minimizing ligand binding domain of the insulin receptor. J Biol Chem 1998; 273:17780-6. [PMID: 9651379 DOI: 10.1074/jbc.273.28.17780] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In order to characterize regions of the insulin receptor that are essential for ligand binding and possibly identify a smaller insulin-binding fragment of the receptor, we have used site-directed mutagenesis to construct a series of insulin receptor deletion mutants. From 112 to 246 amino acids were deleted from the alpha-subunit region comprising amino acids 469-729. The receptor constructs were expressed as soluble insulin receptor IgG fusion proteins in baby hamster kidney cells and were characterized in binding assays by immunoblotting and chemical cross-linking with radiolabeled insulin. The shortest receptor fragment identified was a free monomeric alpha-subunit deleted of amino acids 469-703 and 718-729 (exon 11); the mass of this receptor fragment was found by mass spectrometry to be 70 kDa. This small insulin receptor fragment bound insulin with an affinity (Kd) of 4.4 nM, which is similar to what was found for the full-length ectodomain of the insulin receptor (5.0 nM). Cross-linking experiments confirmed that the 70-kDa receptor fragment specifically bound insulin. In summary we have minimized the insulin binding domain of the insulin receptor by identifying a 70-kDa fragment of the ectodomain that retains insulin binding affinity making this an interesting candidate for detailed structural analysis.
Collapse
Affiliation(s)
- C Kristensen
- Department of Insulin Research, Health Care Discovery, Novo Nordisk, 2880 Bagsvaerd, Denmark.
| | | | | | | |
Collapse
|
5
|
Lee J, Shoelson SE, Pilch PF. Intermolecular phosphorylation between insulin holoreceptors does not stimulate substrate kinase activity. J Biol Chem 1995; 270:31136-40. [PMID: 8537376 DOI: 10.1074/jbc.270.52.31136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We photocoupled benzoylphenylalanineB25, B29 epsilon-biotin insulin (BBpa-insulin) to native insulin receptors to obtain a uniform receptor population with covalently bound, non-dissociable ligand. We employed BBpa-insulin-bound and autophosphorylated (activated) receptor to phosphorylate substrate insulin receptor under conditions where the substrate receptor never interacts with insulin. The substrate receptor becomes phosphorylated in this inter-receptor fashion and reaches a phosphorylation state 50% of the maximal obtainable by autophosphorylation. However, this phosphorylation does not activate the substrate receptor to any measurable degree. We conclude that intermolecular phosphorylation of the insulin holoreceptors is unlikely to be of physiological significance.
Collapse
Affiliation(s)
- J Lee
- Department of Biochemistry, Boston University, School of Medicine, Massachusetts 02118, USA
| | | | | |
Collapse
|
6
|
Goodman DW, Romero G, Isakson P. Antibody binding to the juxtamembrane region of the insulin receptor alters receptor affinity. JOURNAL OF RECEPTOR RESEARCH 1994; 14:381-98. [PMID: 7877136 DOI: 10.3109/10799899409101511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effect of three antibodies that interact with distinct regions of the insulin receptor (the alpha subunit (83-7), the juxtamembrane region near tyrosine 960 (960) or the carboxy terminal region of the beta subunit (CT-1) on insulin binding was examined. Detergent-solubilized insulin receptors from IM-9 cells immobilized on Sepharose beads by 960 antisera bound 2-3 times more 125I-insulin tracer (25-60 pM) than receptors immobilized with either 83-7 or CT-1. Pre-incubation of solubilized receptors with either 83-7 or 960 resulted in equivalent depletion (90%) of insulin binding activity from solubilized IM-9 cell extracts, suggesting that both antibodies were in excess and capable of binding a similar population of receptors. Antibody 960, but not CT-1 or 83-7, also increased insulin binding 2 fold to solubilized receptors precipitated with polyethylene glycol. To determine whether the altered binding observed with antibody 960 was due to increased affinity of the receptor for insulin or appearance of more insulin binding sites, binding studies were performed over a wide range of insulin concentrations. Analysis of the resulting binding curves indicated that 960 increased the affinity of the receptor for insulin 3 fold over control (kd = 0.3 nM for 960, and 0.9 nM for 83-7, respectively). The antibody 960 also specifically increased insulin binding to intact, saponin-permeabilized IM-9 cell membranes. These results indicate that binding of 960 antibody to the juxtamembrane region of the insulin receptor alters the affinity of the receptor for insulin. Since tyrosine 960 in the juxtamembrane region has been suggested to play a role in receptor signalling, changes in receptor conformation in this region that are likely to account for the change in affinity may play a role in signal transduction.
Collapse
Affiliation(s)
- D W Goodman
- Department of Pharmacology, University of Virginia, Charlottesville 22908
| | | | | |
Collapse
|
7
|
Viñals F, Testar X, Palacín M, Zorzano A. Inhibitory effect of fluoride on insulin receptor autophosphorylation and tyrosine kinase activity. Biochem J 1993; 291 ( Pt 2):615-22. [PMID: 7683457 PMCID: PMC1132568 DOI: 10.1042/bj2910615] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fluoride is a nucleophilic reagent which has been reported to inhibit a variety of different enzymes such as esterases, asymmetrical hydrolases and phosphatases. In this report, we demonstrate that fluoride inhibits tyrosine kinase activity of insulin receptors partially purified from rat skeletal muscle and human placenta. Fluoride inhibited in a similar dose-dependent manner both beta-subunit autophosphorylation and tyrosine kinase activity for exogenous substrates. This inhibitory effect of fluoride was not due to the formation of complexes with aluminum and took place in the absence of modifications of insulin-binding properties of the insulin receptor. Fluoride did not complete with the binding site for ATP or Mn2+. Fluoride also inhibited the autophosphorylation and tyrosine kinase activity of receptors for insulin-like growth factor I from human placenta. Addition of fluoride to the pre-phosphorylated insulin receptor produced a slow (time range of minutes) inhibition of receptor kinase activity. Furthermore, fluoride inhibited tyrosine kinase activity in the absence of changes in the phosphorylation of prephosphorylated insulin receptors, and the sensitivity to fluoride was similar to the sensitivity of the unphosphorylated insulin receptor. The effect of fluoride-on tyrosine kinase activity was markedly decreased when insulin receptors were preincubated with the copolymer of glutamate/tyrosine. Prior exposure of receptors to free tyrosine or phosphotyrosine also prevented the inhibitory effect of fluoride. However, the protective effect of tyrosine or phosphotyrosine was maximal at low concentrations, suggesting the interaction of these compounds with the receptor itself rather than with fluoride. These data suggest: (i) that fluoride interacts directly and slowly with the insulin receptor, which causes inhibition of its phosphotransferase activity; (ii) that the binding site of fluoride is not structurally modified by receptor phosphorylation; and (iii) based on the fact that fluoride inhibits phosphotransferase activity in the absence of alterations in the binding of ATP, Mn2+ or insulin, we speculate that fluoride binding might affect the transfer of phosphate from ATP to the tyrosine residues of the beta-subunit of the insulin receptor and to the tyrosine residues of exogenous substrates.
Collapse
Affiliation(s)
- F Viñals
- Department de Bioquímica i Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain
| | | | | | | |
Collapse
|
8
|
|
9
|
Kahn CR, White MF, Shoelson SE, Backer JM, Araki E, Cheatham B, Csermely P, Folli F, Goldstein BJ, Huertas P. The insulin receptor and its substrate: molecular determinants of early events in insulin action. RECENT PROGRESS IN HORMONE RESEARCH 1993; 48:291-339. [PMID: 7680139 DOI: 10.1016/b978-0-12-571148-7.50015-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- C R Kahn
- Joslin Diabetes Center, Department of Medicine Brigham and Women's Hospital, Boston, Massachusetts
| | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Fabry M, Schaefer E, Ellis L, Kojro E, Fahrenholz F, Brandenburg D. Detection of a new hormone contact site within the insulin receptor ectodomain by the use of a novel photoreactive insulin. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50372-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
11
|
Kadowaki H, Kadowaki T, Cama A, Marcus-Samuels B, Rovira A, Bevins CL, Taylor SI. Mutagenesis of lysine 460 in the human insulin receptor. Effects upon receptor recycling and cooperative interactions among binding sites. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)45358-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
12
|
Schaefer EM, Siddle K, Ellis L. Deletion analysis of the human insulin receptor ectodomain reveals independently folded soluble subdomains and insulin binding by a monomeric alpha-subunit. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38291-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
13
|
Kubar J, Rochet N. Basal autophosphorylation of insulin receptor occurs preferentially on the receptor conformation exhibiting high affinity for insulin and stabilizes this conformation. Cell Signal 1990; 2:587-94. [PMID: 2081098 DOI: 10.1016/0898-6568(90)90081-k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Insulin signal transmission through the plasma membrane was studied in terms of relationship between basal autophosphorylation of the beta-subunit and the ability to bind insulin by the alpha-subunit of the insulin receptor. In a cell free system, receptors phosphorylated on tyrosine residues in the absence of insulin were separated from non-phosphorylated receptors using antiphosphotyrosine antibodies. Insulin binding assays were then performed on basally autophosphorylated and on non-phosphorylated receptors. We found that the tyrosine phosphorylated receptors, which corresponded to 25% of the total number of receptors, were accountable for 60-80% of insulin binding. Scatchard representation of binding data has shown that the plot corresponding to tyrosine phosphorylated receptors was localized above, and was steeper than the plot corresponding to non-phosphorylated receptors. These data make it likely that the conformation of alpha-subunit which favours ligand binding is connected to the conformation of beta-subunit which favours phosphate reception on tyrosine residues. Reciprocally, the high-affinity conformation of insulin receptor seems to become stabilized by basal autophosphorylation.
Collapse
Affiliation(s)
- J Kubar
- Institut National de la Santé et de la Recherche Médicale INSERM U145. Faculté de Médecine, Nice, France
| | | |
Collapse
|
14
|
O'Hare T, Pilch PF. Intrinsic kinase activity of the insulin receptor. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1990; 22:315-24. [PMID: 2159922 DOI: 10.1016/0020-711x(90)90132-m] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Since the identification of the insulin receptor by insulin-binding activity almost two decades ago, our understanding of the structure and function of the insulin receptor has progressed tremendously. The importance of the intrinsic tyrosine protein kinase activity of the insulin receptor is implied by the fact that the insulin receptor belongs to a family of receptor tyrosine kinases which play a role in growth control, by experiments demonstrating the intimate association of normal kinase activity and insulin action, and by evidence that the intrinsic kinase activity can be regulated under certain conditions. There are still some major gaps in our knowledge concerning the structure/function of the insulin receptor such as how activation of the intrinsic kinase activity of the receptor leads to altered cellular physiology. The kinase may phosphorylate endogenous substrates or autophosphorylation may simply alter beta subunit conformation so it can then interact with an effector system (i.e. a serine kinase) directly, or indirectly through a G-protein. The truth may lie somewhere between these two pathways.
Collapse
Affiliation(s)
- T O'Hare
- Department of Biochemistry K404, Boston University Medical School, MA 02118
| | | |
Collapse
|
15
|
Kohanski RA. Insulin Receptor Aggregation and Autophosphorylation in the Presence of Cationic Polyamino Acids. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)30033-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|