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Determinants of IGF-II influencing stability, receptor binding and activation. Sci Rep 2022; 12:4695. [PMID: 35304516 PMCID: PMC8933565 DOI: 10.1038/s41598-022-08467-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/28/2022] [Indexed: 11/28/2022] Open
Abstract
Insulin like growth factor II (IGF-II) is involved in metabolic and mitogenic signalling in mammalian cells and plays important roles in normal fetal development and postnatal growth. It is structurally similar to insulin and binds not only with high affinity to the type 1 insulin-like growth factor receptor (IGF-1R) but also to the insulin receptor isoform A (IR-A). As IGF-II expression is commonly upregulated in cancer and its signalling promotes cancer cell survival, an antagonist that blocks IGF-II action without perturbing insulin signalling would be invaluable. The high degree of structural homology between the IR and IGF-1R makes selectively targeting either receptor in the treatment of IGF-II-dependent cancers very challenging. However, there are sequence differences between insulin and IGF-II that convey receptor selectivity and influence binding affinity and signalling outcome. Insulin residue YB16 is a key residue involved in maintaining insulin stability, dimer formation and IR binding. Mutation of this residue to glutamine (as found in IGF-II) results in reduced binding affinity. In this study we sought to determine if the equivalent residue Q18 in IGF-II plays a similar role. We show through site-directed mutagenesis of Q18 that this residue contributes to IGF-II structural integrity, selectivity of IGF-1R/IR binding, but surprisingly does not influence IR-A signalling activation. These findings provide insights into a unique IGF-II residue that can influence receptor binding specificity whilst having little influence on signalling outcome.
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2
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Henderson ST, Brierley GV, Surinya KH, Priebe IK, Catcheside DEA, Wallace JC, Forbes BE, Cosgrove LJ. Delineation of the IGF-II C domain elements involved in binding and activation of the IR-A, IR-B and IGF-IR. Growth Horm IGF Res 2015; 25:20-27. [PMID: 25458127 DOI: 10.1016/j.ghir.2014.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 09/05/2014] [Accepted: 09/26/2014] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Human insulin-like growth factor-I and -II (IGF-I and -II) ligands share a high degree of sequence and structural homology. Despite their similarities, IGF-I and IGF-II exhibit differential receptor binding and activation characteristics. The C domains of IGF-I and IGF-II are the primary determinants of binding specificity to the insulin-like growth factor I receptor (IGF-IR), insulin receptor exon 11- (IR-A) and exon 11+ (IR-B) isoforms. DESIGN Three IGF-II analogues were generated in order to delineate the C domain residues that confer the differential receptor binding affinity and activation properties of the IGFs. Chimeric IGF-II analogues IGF-IICI(N) and IGF-IICI(C) contained partial IGF-I C domain substitutions (IGF-I residues underlined) GYGSSSRRSR and SRVSRRAPQT, respectively. RESULTS The IGF-IICI(N) analogue bound the IR-A and IGF-IR with high affinity but bound the IR-B with a relatively lower affinity than IGF-II, suggesting a negative interaction between the exon-11 encoded peptide in the IR-B and the C-domain. The ability of IGF-IICI(N) to activate receptors and elicit cell viability responses was generally proportional to its relative receptor binding affinity but appeared to act as a partial agonist equivalent to IGF-I when binding and activating the IGF-IR. In contrast, IGF-IICI(C) bound IGF-IR with high affinity but elicited lower receptor activation and cell viability responses. Analogue IGF-IICI(S) contained a truncated IGF-I C domain (GSSSRRAT) and generally displayed a relatively poor ability to bind, activate and elicit viability responses via each receptor. CONCLUSIONS Together, the IGF analogues demonstrate that both flanks of the IGF-II C domain play important roles in the greater ability of IGF-II to bind and activate IR receptors than IGF-I.
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Affiliation(s)
- S T Henderson
- Commonwealth Scientific Industrial Research Organisation, Preventative Health National Research Flagship, Adelaide, South Australia 5000, Australia; School of Biological Sciences, Flinders University, Adelaide, South Australia 5001, Australia
| | - G V Brierley
- Commonwealth Scientific Industrial Research Organisation, Preventative Health National Research Flagship, Adelaide, South Australia 5000, Australia
| | - K H Surinya
- Commonwealth Scientific Industrial Research Organisation, Preventative Health National Research Flagship, Adelaide, South Australia 5000, Australia
| | - I K Priebe
- Commonwealth Scientific Industrial Research Organisation, Preventative Health National Research Flagship, Adelaide, South Australia 5000, Australia
| | - D E A Catcheside
- School of Biological Sciences, Flinders University, Adelaide, South Australia 5001, Australia
| | - J C Wallace
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - B E Forbes
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - L J Cosgrove
- Commonwealth Scientific Industrial Research Organisation, Preventative Health National Research Flagship, Adelaide, South Australia 5000, Australia.
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Malik-Chaudhry HK, Saavedra A, Liao J. A linker strategy for trans-FRET assay to determine activation intermediate of NEDDylation cascade. Biotechnol Bioeng 2014; 111:1288-95. [PMID: 24415255 DOI: 10.1002/bit.25183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 12/27/2013] [Accepted: 01/03/2014] [Indexed: 11/10/2022]
Abstract
Förster resonance energy transfer (FRET) technology has been widely used in biological and biomedical research and is a valuable tool for elucidating molecular interactions in vitro and in vivo. Quantitative FRET analysis is a powerful method for determining biochemical parameters and molecular distances at nanometer levels. Recently, we reported theoretical developments and experimental procedures for determining the dissociation constant, Kd and enzymatic kinetics parameters, Kcat and KM, of protein interactions with the engineered FRET pair, CyPet and YPet. The strong FRET signal from this pair made these developments possible. However, the direct link of fluorescent proteins with proteins of interests may interfere with the folding of some fusion proteins. Here, we report a new protein engineering strategy for improving FRET signals by adding a linker between the fluorescent protein and the targeted protein. This improvement allowed us to follow the covalent conjugation of NEDD8 to its E2 ligase in the presence of E1 and ATP, which was difficult to determine without linker. Three linkers, LAEAAAKEAA, TSGSPGLQEFGT, and LAAALAAA, which are alpha helix or random coil, all significantly improved the FRET signals. Our results show a general methodology for improving trans-FRET signals to effectively determine biochemical reaction intermediates.
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Affiliation(s)
- Harbani Kaur Malik-Chaudhry
- Department of Bioengineering, Center for Bioengineering Research, Bourns College of Engineering, 900 University Avenue, Riverside, California, 92521
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Charlton A, Zachariou M. Tag removal by site-specific cleavage of recombinant fusion proteins. Methods Mol Biol 2011; 681:349-367. [PMID: 20978975 DOI: 10.1007/978-1-60761-913-0_19] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Where an affinity tag has served its purpose it may become desirable to remove it from the protein of interest. This chapter describes the removal of such fusion partners from the intended protein product by cleavage with site-specific endoproteases. Methods to achieve proteolytic cleavage of the fusion proteins are provided, along with techniques for optimising the yield of authentic product.
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Affiliation(s)
- Adam Charlton
- Commonwealth Serum Laboratories Ltd, Parkville, VIC, Australia
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Kavoosi M, Creagh AL, Turner RFB, Kilburn DG, Haynes CA. Direct measurement of the kinetics of CBM9 fusion-tag bioprocessing using luminescence resonance energy transfer. Biotechnol Prog 2009; 25:874-81. [DOI: 10.1002/btpr.88] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Gauguin L, Delaine C, Alvino CL, McNeil KA, Wallace JC, Forbes BE, De Meyts P. Alanine scanning of a putative receptor binding surface of insulin-like growth factor-I. J Biol Chem 2008; 283:20821-9. [PMID: 18502759 DOI: 10.1074/jbc.m802620200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Current evidence supports a binding model in which the insulin molecule contains two binding surfaces, site 1 and site 2, which contact the two halves of the insulin receptor. The interaction of these two surfaces with the insulin receptor results in a high affinity cross-linking of the two receptor alpha subunits and leads to receptor activation. Evidence suggests that insulin-like growth factor-I (IGF-I) may activate the IGF-I receptor in a similar mode. So far IGF-I residues structurally corresponding to the residues of the insulin site 1 together with residues in the C-domain of IGF-I have been found to be important for binding of IGF-I to the IGF-I receptor (e.g. Phe(23), Tyr(24), Tyr(31), Arg(36), Arg(37), Val(44), Tyr(60), and Ala(62)). However, an IGF-I second binding surface similar to site 2 of insulin has not been identified yet. In this study, we have analyzed whether IGF-I residues corresponding to the six residues of the insulin site 2 have a role in high affinity binding of IGF-I to the IGF-I receptor. Six single-substituted IGF-I analogues were produced, each containing an alanine substitution in one of the following positions (corresponding insulin residues in parentheses): Glu(9) (His(B10)), Asp(12) (Glu(B13)), Phe(16) (Leu(B17)), Asp(53) (Ser(A12)), Leu(54) (Leu(A13)), and Glu(58) (Glu(A17)). In addition, two analogues with 2 and 3 combined alanine substitutions were also produced (E9A,D12A IGF-I and E9A,D12A,E58A IGF-I). The results show that introducing alanine in positions Glu(9), Asp(12), Phe(16), Leu(54), and Glu(58) results in a significant reduction in IGF-I receptor binding affinity, whereas alanine substitution at position 53 had no effect on IGF-I receptor binding. The multiple substitutions resulted in a 33-100-fold reduction in IGF-I receptor binding affinity. These data suggest that IGF-I, in addition to the C-domain, uses surfaces similar to those of insulin in contacting its cognate receptor, although the relative contribution of the side chains of homologous residues varies.
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Affiliation(s)
- Lisbeth Gauguin
- Receptor Systems Biology Laboratory, Hagedorn Research Institute, 2820 Gentofte, Denmark.
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Charlton A. Site-specific cleavage of fusion proteins. Methods Mol Biol 2008; 421:211-228. [PMID: 18826057 DOI: 10.1007/978-1-59745-582-4_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Where an affinity tag has served its purpose, it may become desirable to remove it from the protein of interest. This chapter describes the removal of such fusion partners from the intended protein product by cleavage with site-specific endoproteases. Methods to achieve proteolytic cleavage of the fusion proteins are provided, along with techniques for optimizing the yield of authentic product.
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Affiliation(s)
- Adam Charlton
- Industrial Biotechnology, CSIRO Molecular and Health Technology, Australia
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Gauguin L, Klaproth B, Sajid W, Andersen AS, McNeil KA, Forbes BE, De Meyts P. Structural basis for the lower affinity of the insulin-like growth factors for the insulin receptor. J Biol Chem 2007; 283:2604-13. [PMID: 18048361 DOI: 10.1074/jbc.m709220200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin and the insulin-like growth factors (IGFs) bind with high affinity to their cognate receptor and with lower affinity to the noncognate receptor. The major structural difference between insulin and the IGFs is that the IGFs are single chain polypeptides containing A-, B-, C-, and D-domains, whereas the insulin molecule contains separate A- and B-chains. The C-domain of IGF-I is critical for high affinity binding to the insulin-like growth factor I receptor, and lack of a C-domain largely explains the low affinity of insulin for the insulin-like growth factor I receptor. It is less clear why the IGFs have lower affinity for the insulin receptor. In this study, 24 insulin analogues and four IGF analogues were expressed and analyzed to explore the role of amino acid differences in the A- and B-domains between insulin and the IGFs in binding affinity for the insulin receptor. Using the information obtained from single substituted analogues, four multiple substituted analogues were produced. A "quadruple insulin" analogue ([Phe(A8), Ser(A10), Thr(B5), Gln(B16)]Ins) showed affinity as IGF-I for the insulin receptor, and a "sextuple insulin" analogue ([Phe(A8), Ser(A10), Thr(A18), Thr(B5), Thr(B14), Gln(B16)]Ins) showed an affinity close to that of IGF-II for the insulin receptor, whereas a "quadruple IGF-I" analogue ([His(4), Tyr(15), Thr(49), Ile(51)]IGF-I) and a "sextuple IGF-II" analogue ([His(7), Ala(16), Tyr(18), Thr(48), Ile(50), Asn(58)]IGF-II) showed affinities similar to that of insulin for the insulin receptor. The mitogenic potency of these analogues correlated well with the binding properties. Thus, a small number of A- and B-domain substitutions that map to the IGF surface equivalent to the classical binding surface of insulin weaken two hotspots that bind to the insulin receptor site 1.
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Affiliation(s)
- Lisbeth Gauguin
- Receptor Systems Biology Laboratory, Hagedorn Research Institute, 2820 Gentofte, Denmark.
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Delaine C, Alvino CL, McNeil KA, Mulhern TD, Gauguin L, De Meyts P, Jones EY, Brown J, Wallace JC, Forbes BE. A Novel Binding Site for the Human Insulin-like Growth Factor-II (IGF-II)/Mannose 6-Phosphate Receptor on IGF-II. J Biol Chem 2007; 282:18886-94. [PMID: 17475626 DOI: 10.1074/jbc.m700531200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mammalian insulin-like growth factor (IGF)-II/cation-independent mannose 6-phosphate receptor (IGF2R) binds IGF-II with high affinity. By targeting IGF-II to lysosomal degradation, it plays a role in the maintenance of correct IGF-II levels in the circulation and in target tissues. Loss of IGF2R function is associated with tumor progression; therefore, the IGF2R is often referred to as a tumor suppressor. The interaction between IGF2R and IGF-II involves domains 11 and 13 of the 15 extracellular domains of the receptor. Recently, a hydrophobic binding region was identified on domain 11 of the IGF2R. In contrast, relatively little is known about the residues of IGF-II that are involved in IGF2R binding and the determinants of IGF2R specificity for IGF-II over the structurally related IGF-I. Using a series of novel IGF-II analogues and surface plasmon resonance assays, this study revealed a novel binding surface on IGF-II critical for IGF2R binding. The hydrophobic residues Phe(19) and Leu(53) are critical for IGF2R binding, as are residues Thr(16) and Asp(52). Furthermore, Thr(16) was identified as playing a major role in determining why IGF-II, but not IGF-I, binds with high affinity to the IGF2R.
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Affiliation(s)
- Carlie Delaine
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
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Denley A, Bonython ER, Booker GW, Cosgrove LJ, Forbes BE, Ward CW, Wallace JC. Structural determinants for high-affinity binding of insulin-like growth factor II to insulin receptor (IR)-A, the exon 11 minus isoform of the IR. Mol Endocrinol 2004; 18:2502-12. [PMID: 15205474 DOI: 10.1210/me.2004-0183] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The insulin receptor (IR) lacking the alternatively spliced exon 11 (IR-A) is preferentially expressed in fetal and cancer cells. The IR-A has been identified as a high-affinity receptor for insulin and IGF-II but not IGF-I, which it binds with substantially lower affinity. Several cancer cell types that express the IR-A also overexpress IGF-II, suggesting a possible autocrine proliferative loop. To determine the regions of IGF-I and IGF-II responsible for this differential affinity, chimeras were made where the C and D domains were exchanged between IGF-I and IGF-II either singly or together. The abilities of these chimeras to bind to, and activate, the IR-A were investigated. We also investigated the ability of these chimeras to bind and activate the IR exon 11+ isoform (IR-B) and as a positive control, the IGF-I receptor (IGF-1R). We show that the C domain and, to a lesser extent, the D domains represent the principal determinants of the binding differences between IGF-I and IGF-II to IR-A. The C and D domains of IGF-II promote higher affinity binding to the IR-A than the equivalent domains of IGF-I, resulting in an affinity close to that of insulin for the IR-A. The C and D domains also regulate the IR-B binding specificity of the IGFs in a similar manner, although the level of binding for all IGF ligands to IR-B is lower than to IR-A. In contrast, the C and D domains of IGF-I allow higher affinity binding to the IGF-1R than the analogous domains of IGF-II. Activation of IGF-1R by the chimeras reflected their binding affinities whereas the phosphorylation of the two IR isoforms was more complex.
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Affiliation(s)
- Adam Denley
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide 5005, Australia
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Headey SJ, Keizer DW, Yao S, Wallace JC, Bach LA, Norton RS. Binding site for the C-domain of insulin-like growth factor (IGF) binding protein-6 on IGF-II; implications for inhibition of IGF actions. FEBS Lett 2004; 568:19-22. [PMID: 15196913 DOI: 10.1016/j.febslet.2004.04.091] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Revised: 04/16/2004] [Accepted: 04/22/2004] [Indexed: 11/24/2022]
Abstract
Insulin-like growth factors (IGFs) are important mediators of growth and IGF-binding proteins (IGFBPs) 1-6 regulate IGF actions. As IGFBP C-terminal domains contribute to high-affinity IGF binding, we have defined the binding site for the C-domain of IGFBP-6 on IGF-II using NMR. This site lies adjacent to and between the binding sites for the IGFBP N-domain and IGF-I receptor (IGFIR), which have previously been found on opposite sides of the IGF molecule. The C-domain is therefore likely to interfere with IGF binding to the IGFIR, providing a structural basis for the potent inhibitory effects of intact IGFBPs on IGF actions.
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Affiliation(s)
- Stephen J Headey
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3050, Australia
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