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Jiráček J, Selicharová I, Žáková L. Mutations at hypothetical binding site 2 in insulin and insulin-like growth factors 1 and 2. VITAMINS AND HORMONES 2023; 123:187-230. [PMID: 37717985 DOI: 10.1016/bs.vh.2023.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Elucidating how insulin and the related insulin-like growth factors 1 and 2 (IGF-1 and IGF-2) bind to their cellular receptors (IR and IGF-1R) and how the receptors are activated has been the holy grail for generations of scientists. However, deciphering the 3D structure of tyrosine kinase receptors and their hormone-bound complexes has been complicated by the flexible and dimeric nature of the receptors and the dynamic nature of their interaction with hormones. Therefore, mutagenesis of hormones and kinetic studies first became an important tool for studying receptor interactions. It was suggested that hormones could bind to receptors through two binding sites on the hormone surface called site 1 and site 2. A breakthrough in knowledge came with the solution of cryoelectron microscopy (cryoEM) structures of hormone-receptor complexes. In this chapter, we document in detail the mutagenesis of insulin, IGF-1, and IGF-2 with emphasis on modifications of the hypothetical binding site 2 in the hormones, and we discuss the results of structure-activity studies in light of recent cryoEM structures of hormone complexes with IR and IGF-1R.
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Affiliation(s)
- Jiří Jiráček
- From Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic.
| | - Irena Selicharová
- From Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
| | - Lenka Žáková
- From Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
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2
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Glidden MD, Yang Y, Smith NA, Phillips NB, Carr K, Wickramasinghe NP, Ismail-Beigi F, Lawrence MC, Smith BJ, Weiss MA. Solution structure of an ultra-stable single-chain insulin analog connects protein dynamics to a novel mechanism of receptor binding. J Biol Chem 2018; 293:69-88. [PMID: 29114034 PMCID: PMC5766920 DOI: 10.1074/jbc.m117.808667] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/12/2017] [Indexed: 12/11/2022] Open
Abstract
Domain-minimized insulin receptors (IRs) have enabled crystallographic analysis of insulin-bound "micro-receptors." In such structures, the C-terminal segment of the insulin B chain inserts between conserved IR domains, unmasking an invariant receptor-binding surface that spans both insulin A and B chains. This "open" conformation not only rationalizes the inactivity of single-chain insulin (SCI) analogs (in which the A and B chains are directly linked), but also suggests that connecting (C) domains of sufficient length will bind the IR. Here, we report the high-resolution solution structure and dynamics of such an active SCI. The hormone's closed-to-open transition is foreshadowed by segmental flexibility in the native state as probed by heteronuclear NMR spectroscopy and multiple conformer simulations of crystallographic protomers as described in the companion article. We propose a model of the SCI's IR-bound state based on molecular-dynamics simulations of a micro-receptor complex. In this model, a loop defined by the SCI's B and C domains encircles the C-terminal segment of the IR α-subunit. This binding mode predicts a conformational transition between an ultra-stable closed state (in the free hormone) and an active open state (on receptor binding). Optimization of this switch within an ultra-stable SCI promises to circumvent insulin's complex global cold chain. The analog's biphasic activity, which serendipitously resembles current premixed formulations of soluble insulin and microcrystalline suspension, may be of particular utility in the developing world.
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Affiliation(s)
- Michael D Glidden
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106; Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106
| | - Yanwu Yang
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Nicholas A Smith
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Nelson B Phillips
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Kelley Carr
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | | | - Faramarz Ismail-Beigi
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106; Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106; Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Michael C Lawrence
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Brian J Smith
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Michael A Weiss
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106; Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106; Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106.
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Insulin-Like Growth Factor (IGF) Binding Protein-2, Independently of IGF-1, Induces GLUT-4 Translocation and Glucose Uptake in 3T3-L1 Adipocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:3035184. [PMID: 29422987 PMCID: PMC5750484 DOI: 10.1155/2017/3035184] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 10/23/2017] [Indexed: 01/08/2023]
Abstract
Insulin-like growth factor binding protein-2 (IGFBP-2) is the predominant IGF binding protein produced during adipogenesis and is known to increase the insulin-stimulated glucose uptake (GU) in myotubes. We investigated the IGFBP-2-induced changes in basal and insulin-stimulated GU in adipocytes and the underlying mechanisms. We further determined the role of insulin and IGF-1 receptors in mediating the IGFBP-2 and the impact of IGFBP-2 on the IGF-1-induced GU. Fully differentiated 3T3-L1 adipocytes were treated with IGFBP-2 in the presence and absence of insulin and IGF-1. Insulin, IGF-1, and IGFBP-2 induced a dose-dependent increase in GU. IGFBP-2 increased the insulin-induced GU after long-term incubation. The IGFBP-2-induced impact on GU was neither affected by insulin or IGF-1 receptor blockage nor by insulin receptor knockdown. IGFBP-2 significantly increased the phosphorylation of PI3K, Akt, AMPK, TBC1D1, and PKCζ/λ and induced GLUT-4 translocation. Moreover, inhibition of PI3K and AMPK significantly reduced IGFBP-2-stimulated GU. In conclusion, IGFBP-2 stimulates GU in 3T3-L1 adipocytes through activation of PI3K/Akt, AMPK/TBC1D1, and PI3K/PKCζ/λ/GLUT-4 signaling. The stimulatory effect of IGFBP-2 on GU is independent of its binding to IGF-1 and is possibly not mediated through the insulin or IGF-1 receptor. This study highlights the potential role of IGFBP-2 in glucose metabolism.
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Hexnerová R, Křížková K, Fábry M, Sieglová I, Kedrová K, Collinsová M, Ullrichová P, Srb P, Williams C, Crump MP, Tošner Z, Jiráček J, Veverka V, Žáková L. Probing Receptor Specificity by Sampling the Conformational Space of the Insulin-like Growth Factor II C-domain. J Biol Chem 2016; 291:21234-21245. [PMID: 27510031 PMCID: PMC5076530 DOI: 10.1074/jbc.m116.741041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Indexed: 01/22/2023] Open
Abstract
Insulin and insulin-like growth factors I and II are closely related protein hormones. Their distinct evolution has resulted in different yet overlapping biological functions with insulin becoming a key regulator of metabolism, whereas insulin-like growth factors (IGF)-I/II are major growth factors. Insulin and IGFs cross-bind with different affinities to closely related insulin receptor isoforms A and B (IR-A and IR-B) and insulin-like growth factor type I receptor (IGF-1R). Identification of structural determinants in IGFs and insulin that trigger their specific signaling pathways is of increasing importance in designing receptor-specific analogs with potential therapeutic applications. Here, we developed a straightforward protocol for production of recombinant IGF-II and prepared six IGF-II analogs with IGF-I-like mutations. All modified molecules exhibit significantly reduced affinity toward IR-A, particularly the analogs with a Pro-Gln insertion in the C-domain. Moreover, one of the analogs has enhanced binding affinity for IGF-1R due to a synergistic effect of the Pro-Gln insertion and S29N point mutation. Consequently, this analog has almost a 10-fold higher IGF-1R/IR-A binding specificity in comparison with native IGF-II. The established IGF-II purification protocol allowed for cost-effective isotope labeling required for a detailed NMR structural characterization of IGF-II analogs that revealed a link between the altered binding behavior of selected analogs and conformational rearrangement of their C-domains.
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Affiliation(s)
- Rozálie Hexnerová
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic, Faculty of Science, Charles University in Prague, Albertov 6, Prague 128 43, Czech Republic
| | - Květoslava Křížková
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic, Faculty of Science, Charles University in Prague, Albertov 6, Prague 128 43, Czech Republic
| | - Milan Fábry
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic, and
| | - Irena Sieglová
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic
| | - Kateřina Kedrová
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic, Faculty of Science, Charles University in Prague, Albertov 6, Prague 128 43, Czech Republic
| | - Michaela Collinsová
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic
| | - Pavlína Ullrichová
- Department of Analytical Chemistry, University of Chemistry and Technology, Technická 5, 166 28 Prague 6, Czech Republic
| | - Pavel Srb
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic
| | - Christopher Williams
- Department of Organic and Biological Chemistry, School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Matthew P Crump
- Department of Organic and Biological Chemistry, School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Zdeněk Tošner
- Faculty of Science, Charles University in Prague, Albertov 6, Prague 128 43, Czech Republic
| | - Jiří Jiráček
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic
| | - Václav Veverka
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic,
| | - Lenka Žáková
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nám 2, 166 10 Prague 6, Czech Republic,
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Sparkman AM, Schwartz TS, Madden JA, Boyken SE, Ford NB, Serb JM, Bronikowski AM. Rates of molecular evolution vary in vertebrates for insulin-like growth factor-1 (IGF-1), a pleiotropic locus that regulates life history traits. Gen Comp Endocrinol 2012; 178:164-73. [PMID: 22569170 DOI: 10.1016/j.ygcen.2012.04.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 03/24/2012] [Accepted: 04/23/2012] [Indexed: 11/20/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) is a member of the vertebrate insulin/insulin-like growth factor/relaxin gene family necessary for growth, reproduction, and survival at both the cellular and organismal level. Its sequence, protein structure, and function have been characterized in mammals, birds, and fish; however, a notable gap in our current knowledge of the function of IGF-1 and its molecular evolution is information in ectothermic reptiles. To address this disparity, we sequenced the coding region of IGF-1 in 11 reptile species-one crocodilian, three turtles, three lizards, and four snakes. Complete sequencing of the full mRNA transcript of a snake revealed the Ea-isoform, the predominant isoform of IGF-1 also reported in other vertebrate groups. A gene tree of the IGF-1 protein-coding region that incorporated sequences from diverse vertebrate groups showed similarity to the species phylogeny, with the exception of the placement of Testudines as sister group to Aves, due to their high nucleotide sequence similarity. In contrast, long-branch lengths indicate more rapid divergence in IGF-1 among lizards and snakes. Additionally, lepidosaurs (i.e., lizards and snakes) had higher rates of non-synonymous:synonymous substitutions (dN/dS) relative to archosaurs (i.e., birds and crocodilians) and turtles. Tests for positive selection on specific codons within branches and evaluation of the changes in the amino acid properties, suggested positive selection in lepidosaurs on the C domain of IGF-1, which is involved in binding affinity to the IGF-1 receptor. Predicted structural changes suggest that major alterations in protein structure and function may have occurred in reptiles. These data propose new insights into the molecular co-evolution of IGF-1 and its receptors, and ultimately the evolution of IGF-1's role in regulating life-history traits across vertebrates.
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Affiliation(s)
- Amanda M Sparkman
- Department of Ecology, Evolution & Organismal Biology, Iowa State University, Ames, IA 50011, USA
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Treweek TM, Rekas A, Walker MJ, Carver JA. A quantitative NMR spectroscopic examination of the flexibility of the C-terminal extensions of the molecular chaperones, αA- and αB-crystallin. Exp Eye Res 2010; 91:691-9. [PMID: 20732317 DOI: 10.1016/j.exer.2010.08.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 08/09/2010] [Accepted: 08/12/2010] [Indexed: 11/26/2022]
Abstract
The principal lens proteins αA- and αB-crystallin are members of the small heat-shock protein (sHsp) family of molecular chaperone proteins. Via their chaperone action, αA- and αB-crystallin play an important role in maintaining lens transparency by preventing crystallin protein aggregation and precipitation. αB-crystallin is found extensively extralenticularly where it is stress inducible and acts as a chaperone to facilitate general protein stabilization. The structure of either αA- or αB-crystallin is not known nor is the mechanism of their chaperone action. Our earlier (1)H NMR spectroscopic studies determined that mammalian sHsps have a highly dynamic, polar and unstructured region at their extreme C-terminus (summarized in Carver (1999) Prog. Ret. Eye Res. 18, 431). This C-terminal extension acts as a solubilizing agent for the relatively hydrophobic protein and the complex it makes with its target proteins during chaperone action. In this study, αA- and αB-crystallin were (15)N-labelled and their (1)H-(15)N through-bond correlation, heteronuclear single-quantum coherence (HSQC) NMR spectra were assigned via standard methods. (1)H-(15)N spin-lattice (T(1)) and spin-spin (T(2)) relaxation times were measured for αA- and αB-crystallin in the absence and presence of a bound target protein, reduced α-lactalbumin. (1)H-(15)N Nuclear Overhauser Effect (NOE) values provide an accurate measure, on a residue-by-residue basis, of the backbone flexibility of polypeptides. From measurement of these NOE values, it was determined that the flexibility of the extension in αA- and αB-crystallin increased markedly at the extreme C-terminus. By contrast, upon chaperone interaction of αA-crystallin with reduced α-lactalbumin, flexibility was maintained in the extension but was distributed evenly across all residues in the extension. Two mutants of αB-crystallin in its C-terminal region: (i) I159A and I161A and (ii) K175L, have altered chaperone ability (Treweek et al. (2007) PLoS One 2, e1046). Comparison of (1)H-(15)N NOE values for these mutants with wild type αB-crystallin revealed alteration in flexibility of the extension, particularly at the extremity of K175L αB-crystallin, which may affect chaperone ability.
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Affiliation(s)
- Teresa M Treweek
- Graduate School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia.
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7
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Kuang Z, Yao S, McNeil KA, Forbes BE, Wallace JC, Norton RS. Insulin-like growth factor-I (IGF-I): solution properties and NMR chemical shift assignments near physiological pH. Growth Horm IGF Res 2009; 19:226-231. [PMID: 19056307 DOI: 10.1016/j.ghir.2008.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 10/08/2008] [Accepted: 10/17/2008] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Insulin-like growth factor-I (IGF-I) plays important roles in normal growth and development, as well as in disease states, and its structure and function have been studied extensively using nuclear magnetic resonance (NMR) spectroscopy. However, IGF-I typically gives poor quality NMR spectra containing many broad peaks, because of aggregation at the protein concentrations generally required for NMR experiments as well as the internal dynamics of the molecule. The present study was undertaken to determine a reliable set of assignments under more physiological conditions. DESIGN Several reports of chemical shift assignments have been published previously for IGF-I either bound to a ligand or at relatively low pH (approximately 3-4), but there are many contradictions among them, reflecting the poor behaviour of IGF-I. Low pH conditions are also suboptimal for the analysis of interactions between IGF-I and IGF binding proteins (IGFBP) or IGFBP fragments. Spectra were recorded at low concentrations in order to identify conditions of temperature and pH where all peaks could be observed. RESULTS We show that good quality 2D (1)H-(15)N HSQC spectra of (15)N-labelled IGF-I can be obtained at pH 6 and 37 degrees C, much closer to physiological conditions, by using lower IGF-I concentrations (0.05 mM). Surprisingly, at this concentration and temperature, spectra were of better quality at pH 6 than at pH 4, in contrast to previous observations made at millimolar concentrations of IGF-I. We were then also able to assign the chemical shifts of IGF-I at pH 6 and 37 degrees C using 3D heteronuclear spectra recorded on a 0.7 mM (15)N/(13)C-labelled IGF-I sample. CONCLUSION These results provide a valuable resource for future studies of the structure, dynamics, folding, and binding interactions of IGF-I, as well as analogues thereof, by means of NMR spectroscopy.
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Affiliation(s)
- Zhihe Kuang
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
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8
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Williams C, Rezgui D, Prince SN, Zaccheo OJ, Foulstone EJ, Forbes BE, Norton RS, Crosby J, Hassan AB, Crump MP. Structural insights into the interaction of insulin-like growth factor 2 with IGF2R domain 11. Structure 2007; 15:1065-78. [PMID: 17850746 DOI: 10.1016/j.str.2007.07.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 06/18/2007] [Accepted: 07/06/2007] [Indexed: 11/25/2022]
Abstract
The insulin-like growth factor II/mannose-6-phosphate receptor (IGF2R) mediates trafficking of mannose-6-phosphate (M6P)-containing proteins and the mitogenic hormone IGF2. IGF2R also plays an important role as a tumor suppressor, as mutation is frequently associated with human carcinogenesis. IGF2 binds to domain 11, one of 15 extracellular domains on IGF2R. The crystal structure of domain 11 and the solution structure of IGF2 have been reported, but, to date, there has been limited success when using crystallography to study the interaction of IGFs with their binding partners. As an approach to investigate the interaction between IGF2 and IGF2R, we have used heteronuclear NMR in combination with existing mutagenesis data to derive models of the domain 11-IGF2 complex by using the program HADDOCK. The models reveal that the molecular interaction is driven by critical hydrophobic residues on IGF2 and IGF2R, while a ring of flexible, charged residues on IGF2R may modulate binding.
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Affiliation(s)
- Christopher Williams
- Department of Organic and Biological Chemistry, School of Chemistry, Cantock's Close, University of Bristol, Bristol, United Kingdom
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Kuang Z, Yao S, McNeil KA, Thompson JA, Bach LA, Forbes BE, Wallace JC, Norton RS. Cooperativity of the N- and C-terminal domains of insulin-like growth factor (IGF) binding protein 2 in IGF binding. Biochemistry 2007; 46:13720-32. [PMID: 17985932 DOI: 10.1021/bi701251d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A family of six insulin-like growth factor (IGF) binding proteins (IGFBP-1-6) binds IGF-I and IGF-II with high affinity and thus regulates their bioavailability and biological functions. IGFBPs consist of N- and C-terminal domains, which are highly conserved and cysteine-rich, joined by a variable linker domain. The role of the C-domain in IGF binding is not completely understood in that C-domain fragments have very low or even undetectable IGF binding affinity, but loss of the C-domain dramatically disrupts IGF binding by IGFBPs. We recently reported the solution structure and backbone dynamics of the C-domain of IGFBP-2 (C-BP-2) and identified a pH-dependent heparin binding site [Kuang, Z., Yao, S., Keizer, D. W., Wang, C. C., Bach, L. A., Forbes, B. E., Wallace, J. C., and Norton, R. S. (2006) Structure, dynamics and heparin binding of the C-terminal domain of insulin-like growth factor-binding protein-2 (IGFBP-2), J. Mol. Biol. 364, 690-704]. Here, we have analyzed the molecular interactions among the N-domain of IGFBP-2 (N-BP-2), C-BP-2, and IGFs using cross-linking and nuclear magnetic resonance (NMR) spectroscopy. The binding of C-BP-2 to the IGF-I.N-BP-2 binary complex was significantly stronger than the binding of C-BP-2 to IGF-I alone, switching from intermediate exchange to slow exchange on the NMR time scale. A conformational change or stabilization of the IGF-I Phe49-Leu54 region and the Phe49 aromatic ring upon binding to the N-domains, as well as an interdomain interaction between N-BP-2 and C-BP-2 (which is also detectable in the absence of ligand), may contribute to this cooperativity in IGF binding. Glycosaminoglycan binding by IGFBPs can affect their IGF binding although the effects appear to differ among different IGFBPs; here, we found that heparin bound to the IGF-I.N-BP-2.C-BP-2 ternary complex, but did not cause it to dissociate.
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Affiliation(s)
- Zhihe Kuang
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3050, Australia
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10
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Denley A, Wang CC, McNeil KA, Walenkamp MJE, van Duyvenvoorde H, Wit JM, Wallace JC, Norton RS, Karperien M, Forbes BE. Structural and functional characteristics of the Val44Met insulin-like growth factor I missense mutation: correlation with effects on growth and development. Mol Endocrinol 2004; 19:711-21. [PMID: 15576456 DOI: 10.1210/me.2004-0409] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have previously described the phenotype resulting from a missense mutation in the IGF-I gene, which leads to expression of IGF-I with a methionine instead of a valine at position 44 (Val44Met IGF-I). This mutation caused severe growth and mental retardation as well as deafness evident at birth and growth retardation in childhood, but is relatively well tolerated in adulthood. We have conducted a biochemical and structural analysis of Val44Met IGF-I to provide a molecular basis for the phenotype observed. Val44Met IGF-I exhibits a 90-fold decrease in type 1 IGF receptor (IGF-1R) binding compared with wild-type human IGF-I and only poorly stimulates autophosphorylation of the IGF-1R. The ability of Val44Met IGF-I to signal via the extracellular signal-regulated kinase 1/2 and Akt/protein kinase B pathways and to stimulate DNA synthesis is correspondingly poorer. Binding or activation of both insulin receptor isoforms is not detectable even at micromolar concentrations. However, Val44Met IGF-I binds IGF-binding protein-2 (IGFBP-2), IGFBP-3, and IGFBP-6 with equal affinity to IGF-I, suggesting the maintenance of overall structure, particularly in the IGFBP binding domain. Structural analysis by nuclear magnetic resonance confirms retention of near-native structure with only local side-chain disruptions despite the significant loss of function. To our knowledge, our results provide the first structural study of a naturally occurring mutant human IGF-I associated with growth and developmental abnormalities and identifies Val44 as an essential residue involved in the IGF-IGF-1R interaction.
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Affiliation(s)
- Adam Denley
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, 5005 South Australia
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11
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Schaffer ML, Deshayes K, Nakamura G, Sidhu S, Skelton NJ. Complex with a phage display-derived peptide provides insight into the function of insulin-like growth factor I. Biochemistry 2003; 42:9324-34. [PMID: 12899619 DOI: 10.1021/bi034386c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dramatic improvement in the NMR spectra of insulin-like growth factor I (IGF-I) in the presence of a peptide identified from a phage display library has allowed for the first time the determination of a high-resolution solution structure for much of IGF-I. The three helices of IGF-I in this complex have an arrangement similar to that seen in high-resolution crystal structures of IGF-I and insulin, although there are differences in the conformation and precise location of helix 3. A cluster of hydrophobic and basic side chains within the turn-helix motif of the peptide contact a hydrophobic patch on helices 1 and 3 of IGF-I. The importance of this patch for tight binding was verified using alanine scanning mutagenesis of the peptide in two different phage display formats. Consistent with its antagonistic activity, the peptide binds to a region implicated by mutagenesis studies to be important for association with IGF binding proteins (IGFBPs). The ability of the peptide to also inhibit signaling has important implications for the manner in which IGF-I interacts with its receptor. Interestingly, the peptide uses the same binding site as detergent and a fragment of IGFBP-5 identified in other IGF-I complexes. The ligand-induced structural variability of helix 3 in these complexes suggests that exchange between such conformations may be the source of the dynamic nature of free IGF-I and likely has functional significance for the ability of IGF-I to recognize two signaling receptors and six binding proteins with high affinity.
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Affiliation(s)
- Michelle L Schaffer
- Department of Protein Engineering, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, USA
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12
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Vajdos FF, Ultsch M, Schaffer ML, Deshayes KD, Liu J, Skelton NJ, de Vos AM. Crystal structure of human insulin-like growth factor-1: detergent binding inhibits binding protein interactions. Biochemistry 2001; 40:11022-9. [PMID: 11551198 DOI: 10.1021/bi0109111] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Despite efforts spanning considerably more than a decade, a high-resolution view of the family of proteins known as insulin-like growth factors (IGFs) has remained elusive. IGF-1 consists of three helical segments which are connected by a 12-residue linker known as the C-region. NMR studies of members of this family reveal a dynamic structure with a topology resembling insulin but little structural definition in the C-region. We have crystallized IGF-1 in the presence of the detergent deoxy big CHAPS, and determined its structure at 1.8 A resolution by multiwavelength anomalous diffraction, exploiting the anomalous scattering of a single bromide ion and six of the seven sulfur atoms of IGF-1. The structure reveals a well-defined conformation for much of the C-region, which extends away from the core of IGF-1 and has residues known to be involved in receptor binding prominently displayed in a type II beta-turn. In the crystal, these residues form a dimer interface, but analytical ultracentrifugation experiments demonstrate that at physiological concentrations IGF-1 is monomeric. A single detergent molecule contacts residues known to be important for IGF-1 binding protein (IGFBP) interactions. Biophysical and biochemical data show that the detergent binds to IGF-1 specifically and blocks binding of IGFBP-1 and IGFBP-3.
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Affiliation(s)
- F F Vajdos
- Department of Protein Engineering, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, USA
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13
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Skelton NJ, Chen YM, Dubree N, Quan C, Jackson DY, Cochran A, Zobel K, Deshayes K, Baca M, Pisabarro MT, Lowman HB. Structure-function analysis of a phage display-derived peptide that binds to insulin-like growth factor binding protein 1. Biochemistry 2001; 40:8487-98. [PMID: 11456486 DOI: 10.1021/bi0103866] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Highly structured, peptide antagonists of the interaction between insulin-like growth factor 1 (IGF-I) and IGF binding protein 1 (IGFBP-1) have recently been discovered by phage display of naïve peptide libraries [Lowman, H. B., et al. (1998) Biochemistry 37, 8870--8878]. We now report a detailed analysis of the features of this turn-helix peptide motif that are necessary for IGFBP-1 binding and structural integrity. Further rounds of phage randomization indicate the importance of residues contributing to a hydrophobic patch on one face of the helix. Alanine-scanning substitutions confirm that the hydrophobic residues are necessary for binding. However, structural analysis by NMR spectroscopy indicates that some of these analogues are less well folded. Structured, high-affinity analogues that lack the disulfide bond were prepared by introducing a covalent constraint between side chains at positions i and i + 7 or i + 8 within the helix. Analogues based on this scaffold demonstrate that a helical conformation is present in the bound state, and that hydrophobic side chains in this helix, and residues immediately preceding it, interact with IGFBP-1. By comparison of alanine scanning data for IGF-I and the turn-helix peptide, we propose a model for common surface features of these molecules that recognize IGFBP-1.
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Affiliation(s)
- N J Skelton
- Department of Protein Engineering, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, USA.
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14
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Żesławski W, Beisel HG, Kamionka M, Kalus W, Engh RA, Huber R, Lang K, Holak TA. The interaction of insulin-like growth factor-I with the N-terminal domain of IGFBP-5. EMBO J 2001; 20:3638-44. [PMID: 11447105 PMCID: PMC125553 DOI: 10.1093/emboj/20.14.3638] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Insulin-like growth factors (IGFs) are key regulators of cell proliferation, differentiation and transformation, and are thus pivotal in cancer, especially breast, prostate and colon neoplasms. They are also important in many neurological and bone disorders. Their potent mitogenic and anti-apoptotic actions depend primarily on their availability to bind to the cell surface IGF-I receptor. In circulation and interstitial fluids, IGFs are largely unavailable as they are tightly associated with IGF-binding proteins (IGFBPs) and are released after IGFBP proteolysis. Here we report the 2.1 A crystal structure of the complex of IGF-I bound to the N-terminal IGF-binding domain of IGFBP-5 (mini-IGFBP-5), a prototype interaction for all N-terminal domains of the IGFBP family. The principal interactions in the complex comprise interlaced hydrophobic side chains that protrude from both IGF-I and the IGFBP-5 fragment and a surrounding network of polar interactions. A solvent-exposed hydrophobic patch is located on the IGF-I pole opposite to the mini-IGFBP-5 binding region and marks the IGF-I receptor binding site.
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Affiliation(s)
| | | | | | | | - Richard A. Engh
- Max Planck Institute for Biochemistry, D-82152 Martinsried and
Roche Diagnostics GmbH, Pharmaceutical Research, D-82377 Penzberg, Germany Corresponding author e-mail:
| | | | - Kurt Lang
- Max Planck Institute for Biochemistry, D-82152 Martinsried and
Roche Diagnostics GmbH, Pharmaceutical Research, D-82377 Penzberg, Germany Corresponding author e-mail:
| | - Tad A. Holak
- Max Planck Institute for Biochemistry, D-82152 Martinsried and
Roche Diagnostics GmbH, Pharmaceutical Research, D-82377 Penzberg, Germany Corresponding author e-mail:
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15
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The interaction of Insulin-like Growth Factors (IGFs) with Insulin-like Growth Factor Binding Proteins (IGFBPs): a review. ACTA ACUST UNITED AC 2001. [DOI: 10.1007/bf02446511] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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16
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Horney MJ, Evangelista CA, Rosenzweig SA. Synthesis and characterization of insulin-like growth factor (IGF)-1 photoprobes selective for the IGF-binding proteins (IGFBPS). photoaffinity labeling of the IGF-binding domain on IGFBP-2. J Biol Chem 2001; 276:2880-9. [PMID: 11063745 DOI: 10.1074/jbc.m007526200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Elevated insulin-like growth factor (IGF)-1 levels are prognostic for the development of prostate and breast cancers and exacerbate the complications of diabetes. In each case, perturbation of the balance between IGF-1/2, the IGF-1 receptor, and the IGF-binding proteins (IGFBPs) leads to elevated IGF-1 sensitivity. Blockade of IGF action in these diseases would be clinically significant. Unfortunately, effective IGF antagonists are currently unavailable. The IGFBPs exhibit high affinity and specificity for the IGFs and serve as natural IGF antagonists, limiting their mitogenic/anti-apoptotic effects. As an initial step in designing IGFBP-based agents that antagonize IGF action, we have begun to analyze the structure of the IGF-binding site on IGFBP-2. To this end, two IGF-1 photoprobes, N(alphaGly1)-(4-azidobenzoyl)-IGF-1 (abG(1)IGF-1) and N(alphaGly1)-([2-6-(biotinamido)-2(p-azidobenzamido)hexanoamido]ethyl-1,3'-dithiopropionoyl)-IGF-1 (bedG(1)IGF-1), selective for the IGFBPs were synthesized by derivatization of the alpha-amino group of Gly(1), known to be part of the IGFBP-binding domain. Mass spectrometric analysis of the reduced, alkylated, and trypsin-digested abG(1)IGF-1.recombinant human IGFBP-2 (rhIGFBP-2) complex indicated photoincorporation near the carboxyl terminus of rhIGFBP-2, between residues 266 and 287. Mass spectrometric analysis of avidin-purified tryptic peptides of the bedG(1)IGF-1.rhIGFBP-2 complex revealed photoincorporation within residues 212-227. Taken together, these data indicate that the IGFBP-binding domain on IGF-1 contacts the distal third of IGFBP-2, providing evidence that the IGF-1-binding domain is located within the C terminus of IGFBP-2.
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Affiliation(s)
- M J Horney
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston 29425, USA
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17
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Lien S, Milner SJ, Graham LD, Wallace JC, Francis GL. Linkers for improved cleavage of fusion proteins with an engineered ?-lytic protease. Biotechnol Bioeng 2001. [DOI: 10.1002/bit.1124] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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