Fig 2: Dissection of the interaction of IGF-I with binding site 1 of IGF-1R. a Conformation of L1-ß2 (light blue) and aCT? (magenta) in the apo IGF-1R?ß structure, compared with b, its conformation in the IGF-I liganded IGF-1R?ß structure. c Interaction between B domain of IGF-I (black) and the IGF-1R site 1 elements of L1-ß2 (light blue) and aCT? (magenta). The A domain of IGF-I (located in the foreground) is omitted for clarity. d Interaction between A domain of IGF-I (black) and the IGF-1R site 1 element aCT? (magenta); no interaction is observed between the A domain and L1-ß2 (light blue). The IGF-I B domain is in white

Fig 3: Interaction of Fv 24–60 with IGF-1R?ß. a Interaction of residues of domain CR of IGF-1R?ß (red) with Fv 24–60 (variable heavy chain domain pink; variable light chain domain light grey). b Displacement by Fv 24–60 of the peptide loop formed by IGF-1R?ß CR residues 254–265 towards the IGF-I binding site. The yellow ribbon is that of IGF-1R domain CR within the crystal structure of the isolated L1-CR-L2 fragment of IGF-1R obtained in the absence of attached Fv (PDB entry 1IGR25), overlaid onto that of the IGF-I-bound IGF-1R?ß structure (red) on the basis of common domain L1. Red sphere: IGF-I Asn26; blue sphere: IGF-I Pro39. The connecting IGF-I domain C residues 27–38 (indicated putatively by a blue dashed line) are disordered

Fig 4: Induced fit binding of ligand to IGF-1R and IR. a Proposed kinetic scheme. S1, S2: site 1 and site 2 on one receptor monomer; S1?, S2?: site 1 and site 2 on the opposing receptor monomer. Black filled circle: hot ligand (i.e., IGF-I, IGF-II or insulin). Grey circle: cold ligand (i.e., IGF-I, IGF-II or insulin). a1 and d1: ligand association and dissociation rate constants for the high-affinity site. a2 and d2: ligand association and dissociation rate constants for doubly liganded, symmetrical receptor conformation. a3 and d3: association and dissociation rate constant for binding of a third insulin molecule (IR only, not applicable to IGF-1R). b Plot for accelerated dissociation of a pre-bound tracer-labelled ligand by cold (unlabelled) ligand. The dissociation time was 20 min. The experimental data were as described previously (reproduced in Supplementary Table 4)18 and are shown as blue triangles for IGF-1 and red diamonds for insulin, with the fit of the induced-fit model to these data shown as lines (IGF-I blue; insulin red)

Fig 5: Short-term HS does not affect insulin signaling or CaMKII in isolated skeletal muscle. Isolated epitrochlearis muscle was incubated in medium for 0 (control), 10, or 30 min at 42°C. Muscle was also incubated in the presence of 1 µmol/L insulin for 30 min at 35°C or contracted by electrical stimulation (ES) at 35°C. Muscle was subjected to Western blot analysis for phosphorylated IR (A), phosphorylated Akt (B), or phosphorylated CaMKII (C). Fold increases are expressed relative to the level in muscles of the control group. The values are mean ± SD; n = 5–6 (A), 6–7 (B), and 3–14 (C). *P < 0.05 versus corresponding control. Representative immunoblots are shown.