Figure 2.

Functional analyses of TYK2 variants. Human TYK2-deficient U1A cell line was transfected with the different TYK2 variants and clones stably expressing these variants were selected. Clones were stimulated with the indicated doses of IFNα for 15 min, and the level of phosphorylation of TYK2 variants and STAT1–3 transcription factors was assessed by Western blot. Arrowheads point out the size of specific proteins and molecular weight markers (kDa) are noted on the right. Quantification of phosphorylated proteins is relative to TYK2 total protein (to account for TYK2 expression differences among cell lines) and then to Tubulin (shown under each lane/membrane). Values are expressed as percentage of the highest value of each membrane. WT: wild-type TYK2; V678F: catalytically hyperactive TYK2; K930R: kinase-dead TYK2 (ATP-binding site mutant); R832W, R425H, and S431G: disease-associated TYK2 variants. A representative result of three independent experiments is shown (Figure S2).