Journal: Cell Discovery
Article Title: Phase separation of insulin receptor substrate 1 drives the formation of insulin/IGF-1 signalosomes
doi: 10.1038/s41421-022-00426-x
Figure Lengend Snippet: a Confocal images of GFP-mIRS-1 foci in C2C12-IRS-1 KO/GFP-mIRS-1 cells treated with control or with IGF-1-conditioned (100 ng/mL) medium for 2.5 min. Scale bar, 10 µm. Quantitative analysis of number of mIRS-1 puncta is shown with results presented as violin plots. *** p < 0.001. b FLAG-tagged and GFP-tagged mIRS-1 were co-transfected into 293 T cells. Cells were serum starved for 16 h followed by IGF-1 stimulation and coimmunoprecipitation analysis. c Immunofluorescence staining of endogenous p-IRS-1 (Y608) antibody in C2C12-IRS-1 KO/GFP-mIRS-1 cells treated for 5 min with control medium or IGF-1-conditioned medium. Scale bar, 5 µm. Line scan showing the related intensity profiles of mIRS-1 with p-IRS-1 (Y608). The puncta diameter was quantified ( n = 69). Data in the bar graphs represent the means ± SEM. d Immunoblot analysis of Y608 residue tyrosine phosphorylation of FLAG-mIRS-1 purified from starved or insulin-stimulated (15 min) 293 T cells. Quantification result is shown as means ± SEM. ** p < 0.001. e DIC images of FLAG-mIRS-1 purified from starved or insulin-stimulated (15 min) 293 T cells. The proteins (1 μM) were incubated with phase separation buffer at room temperature for 20 min. Scale bar, 20 µm. Quantification result is shown as means ± SD. ** p < 0.01. f Scheme indicating the location of the nine tyrosine residues of YXXM motifs in mIRS-1. g The nine tyrosine residues of the YXXM motifs in mIRS-1 were replaced by alanine residues. h Immunoblot analysis of the IRS-1 expression levels in C2C12 wildtype, C2C12-IRS-1 KO/GFP-mIRS-1, and C2C12-IRS-1 KO/GFP-mIRS-1 9YA cell lines. i Confocal images of GFP-tagged mIRS-1 or 9YA mutant in C2C12-IRS-1 KO/GFP-mIRS-1 or C2C12-IRS-1 KO/GFP-mIRS-1 9YA cell lines. Scale bar, 10 µm. Quantification results of GFP-mIRS-1 or 9YA puncta are shown and presented as violin plots. **** p < 0.0001. j DIC images of FLAG-mIRS-1 or FLAG-mIRS-1 9YA purified from 293 T cells. The proteins (1 μM) were incubated with phase separation buffer at room temperature for 20 min. Scale bar, 20 µm. k Phase diagrams of mIRS-1 wildtype, ΔSAR, and 9YA mutant proteins purified from insulin-stimulated cell lines in 50 mM Tris (pH 7.5), 2% (w/v) PEG-8000, and sodium chloride (ranging from 50–1200 mM).
Article Snippet: The purified proteins were added to phase separation Buffer (50 mM Tris-HCl pH 7.5, 10% glycerol, 1 mM DTT, 2% PEG-8000 (Sangon biotech, A100159)).
Techniques: Control, Transfection, Immunofluorescence, Staining, Western Blot, Residue, Phospho-proteomics, Purification, Incubation, Expressing, Mutagenesis