Fig 2: Structural basis for the assembly of human type I OSM receptor complex (hOSM/hgp130/hLIFR complex).Close-up views of hOSM-hgp130 Site 2 (a) and hOSM-hLIFR Site 3 (b) binding interfaces shown in cartoon form, with residues involved in binding shown in stick representation. Each interface was shown in two orientations. All-atom real-space refined model of the complex interaction core region shown in Fig. 1d was used for the analysis. Buried surface areas of the two binding interfaces were calculated by PDBePISA.

Fig 3: Cryo-EM structure of human type I OSM receptor complex (hOSM/hgp130/hLIFR complex).a Schematic representation of human OSM/gp130/LIFR complex assembly, with hLIFR, hgp130, and hOSM colored in purple, blue, and dark red, respectively. Transmembrane (TM) region and intracellular domains (ICD) of hLIFR and hgp130 were excluded from the constructs and were colored in gray. b Representative 2D class averages of human OSM/gp130/LIFR complex with full extracellular assembly. c 3.59 Å cryo-EM density map (Map 1) was overlaid with transparent Map 2 (3.99 Å). The assembly core regions of Map 1 (hOSM, hgp130 D2D3, and hLIFR D3D4) were colored as in (a) while the remaining parts of the map were colored in gray. d The atomic model of human OSM/gp130/LIFR complex assembly core region (hOSM, hgp130 D2D3, and hLIFR D3D4) manually built and refined against Map 1 was shown in cartoon form in two orientations. Glycosylation sites in this region were highlighted in stick representation. e 3.99 Å cryo-EM density map (Map 2) of human OSM/gp130/LIFR complex colored as in (a). f Model of complete extracellular assembly of human OSM/gp130/LIFR complex depicted in C-alpha ribbon traces. g Side view of the full extracellular assembly model in transparent Map 2. Approximate distances between the bottom centers of hLIFR and hgp130 juxtamembrane domains is estimated.

Fig 4: Cryo-EM structure of mouse type II OSM receptor complex (mOSM/mgp130/mOSMR complex).a Schematic representation of mouse OSM/gp130/OSMR complex assembly, with mOSMR, mgp130, and mOSM colored in gold, light blue, and brown, respectively. Transmembrane (TM) region and intracellular domains (ICD) of mOSMR and mgp130 were excluded from the constructs and were colored in gray. b Representative 2D class averages of mouse OSM/gp130/OSMR complex with full extracellular assembly. c 3.46 Å cryo-EM density map (Map 1) was overlaid with transparent Map 2 (3.67 Å). The assembly core regions of Map 1 (mOSM, mgp130 D2D3, and mOSMR D2D3) were colored as in (a) while the remaining parts of the map were colored in gray. d The atomic model of mouse OSM/gp130/OSMR complex assembly core region (mOSM, mgp130 D2D3, and mOSMR D2D3) manually built and refined against Map 1 was shown in cartoon form in two orientations. Glycosylation sites in this region were highlighted in stick representation. e 3.67 Å cryo-EM density map (Map 2) of mouse OSM/gp130/OSMR complex colored as in (a). f Model of complete extracellular assembly of mouse OSM/gp130/OSMR complex depicted in C-alpha ribbon traces. g Side view of the full extracellular assembly model in transparent Map 2. Approximate distances between the bottom centers of mOSMR and mgp130 juxtamembrane domains is estimated.