title: Insulin-Insulin-like Growth Factors Hybrids as Molecular Probes of Hormone:Receptor Binding Specificity.
abstract: Insulin, insulin-like growth factors 1 and 2 (IGF-1 and -2, respectively), and their receptors (IR and IGF-1R) are the key elements of a complex hormonal system that is essential for the development and functioning of humans. The C and D domains of IGFs (absent in insulin) likely play important roles in the differential binding of IGF-1 and -2 to IGF-1R and to the isoforms of IR (IR-A and IR-B) and specific activation of these receptors. Here, we attempted to probe the impact of IGF-1 and IGF-2 D domains (DI and DII, respectively) and the IGF-2 C domain (CII) on the receptor specificity of these hormones. For this, we made two types of insulin hybrid analogues: (i) with the C-terminus of the insulin A chain extended by the amino acids from the DI and DII domains and (ii) with the C-terminus of the insulin B chain extended by some amino acids derived from the CII domain. The receptor binding affinities of these analogues and their receptor autophosphorylation potentials were characterized. Our results indicate that the DI domain has a more negative impact than the DII domain does on binding to IR, and that the DI domain Pro-Leu-Lys residues are important factors for a different IR-A versus IR-B binding affinity of IGF-1. We also showed that the additions of amino acids that partially "mimic" the CII domain, to the C-terminus of the insulin B chain, change the binding and autophosphorylation specificity of insulin in favor of the "metabolic" IR-B isoform. This opens new venues for rational enhancement of insulin IR-B specificity by modifications beyond the C-terminus of its B chain.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic v.v.i. , Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.|Charles University in Prague , Faculty of Science, Department of Biochemistry, Hlavova 8, 128 43 Praha 2, Czech Republic.
authors.forename: Květoslava
authors.initials: K
authors.lastname: Křížková
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic v.v.i. , Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.|Charles University in Prague , Faculty of Science, Department of Biochemistry, Hlavova 8, 128 43 Praha 2, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Chrudinová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic v.v.i. , Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.|Charles University in Prague , Faculty of Science, Department of Biochemistry, Hlavova 8, 128 43 Praha 2, Czech Republic.
authors.forename: Anna
authors.initials: A
authors.lastname: Povalová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic v.v.i. , Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.
authors.forename: Irena
authors.initials: I
authors.lastname: Selicharová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic v.v.i. , Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.
authors.forename: Michaela
authors.initials: M
authors.lastname: Collinsová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic v.v.i. , Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.
authors.forename: Václav
authors.initials: V
authors.lastname: Vaněk
authors.affiliation: York Structural Biology Laboratory, Department of Chemistry, University of York , Heslington, York YO10 5DD, United Kingdom.
authors.forename: Andrzej M
authors.initials: AM
authors.lastname: Brzozowski
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic v.v.i. , Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Jiráček
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic v.v.i. , Flemingovo nám. 2, 166 10 Praha 6, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Žáková
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D008214:Lymphocytes / Q000166:cytology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D015335:Molecular Probes / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D015335:Molecular Probes; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin