Fig. 6: MS3-6 reduces STAT3 Y705 phosphorylation levels upon IL-22 stimulation.

a Representative immunoblot from five (pY705) and three (pS727) independent experiments of STAT3 phosphorylation levels following IL-6 and IL-22 stimulation for 15 min. All immunoblots are available as Source data Files. b Quantification (mean ± SD) of the results in a from all independent experiments for the indicated STAT3 phosphorylation sites. Significance according to an unpaired two-tailed t-test analysis: ****P ≤ 0.0001. c Flow cytometry analysis on Ba/F3 cells expressing IL-22R. Four hours after electroporation of the monobody vectors (15 µg), cells were stimulated with IL-22 (500 ng ml⁻¹) and staining was performed. A live-cell gating strategy was applied and phospho-STAT3 staining was analyzed in cMyc-tag⁺ and cMyc-tag⁻ cells. Unstimulated cells are reported as colored bar plot and stimulated cells are reported as empty bar plots. d Quantification of pY705-STAT3 staining from c. Data are presented as mean ± SEM of two independent experiments performed in duplicates (n = 4). Significance according to a two-tailed Mann–Whitney test analysis: *P ≤ 0.05. e Upper panel, schematic representation of GST fusion proteins with intracytoplasmic domain of IL-22R. Lower panel, COS-7 cells were seeded in six-well plate and transfected with a vector coding for the GST-fusion protein or STAT3. Cells were lysed and the recovered STAT3 protein was mixed with the recombinant monobody (10 µM) before incubation with IL-22R-GST overnight. Proteins eluted on GST SpinTrap columns as well as input samples were analyzed by western blot with an anti-STAT3 antibody. Membrane was then re-probed with anti-GST and anti-tag antibodies. Source data are provided as a source data file.