FIGURE 8.

A part of the C-terminal domain of IL-23R is sufficient for STAT3 activation. A, a series of deletion variants starting from Y416F-Δ503 to the mutant Y426F/Y504F/Y542F/Y626F were generated and stably transduced into Ba/F3-gp130 cells containing the IL-12Rβ1. Resulting Ba/F3 cell lines were washed three times with PBS, starved, and stimulated for 10 min with 0.2% HIL-23. Equal amounts of protein were loaded onto SDS gels. Western blotting was performed using antibodies specific for phospho-STAT3 and STAT3. Data are representative for at least two experiments. Presented Western blots originate from different membranes and are therefore separated by black lines. B, equal numbers of stably transduced Ba/F3 cells were cultured for 2 days in the presence of 0.2% HIL-6 or 0.2% HIL-23 or without cytokine. Proliferation was measured with the colorimetric CellTiter-Blue® cell viability assay. Values represent the mean value of three repetitions and were normalized. For comparison, n-fold proliferation was calculated by setting the negative control of each Ba/F3 cell line to a value of 1. Data are representative of at least two independent experiments. Error bars, S.D.