Figure 8.

BLK facilitates TLR/IL-1R–mediated signal transduction. (A) Effects of BLK and its mutants on the oligomerization of IRAK1. HEK293 cells (4 × 10⁷) were transfected with IRAK1 and BLK or its mutants for 24 h. Cells were collected and lysed, followed by gel filtration. Fraction size was calibrated with the gel filtration standard (151-1901; Bio-Rad). (B) Effects of BLK deficiency on IL-1β–induced oligomerization of endogenous IRAK1. BLK-deficient and control U87MG cells (1 × 10⁸) were untreated or treated with IL-1β (20 ng/ml) for 10 min before gel filtration. Fraction size was calibrated with the gel filtration standard. (C) Effects of BLK deficiency on IL-1β–induced hyperphosphorylation of IRAK1 and subsequent recruitment of IRAK1 to TRAF6. BLK-deficient and control U87MG cells (2 × 10⁷) (BLK-KO #1 plasmids were used) were left untreated or treated with IL-1β (20 ng/ml) for the indicated times before coimmunoprecipitation (IP) and immunoblot (IB) analysis. Data are representative of three independent experiments with similar results. Source data are available for this figure: SourceData F8.