FunctionBinds to the IL-1 type I receptor following IL-1 engagement, triggering intracellular signaling cascades leading to transcriptional up-regulation and mRNA stabilization. Isoform 1 binds rapidly but is then degraded allowing isoform 2 to mediate a slower, more sustained response to the cytokine. Isoform 2 is inactive suggesting that the kinase activity of this enzyme is not required for IL-1 signaling. Once phosphorylated, IRAK1 recruits the adapter protein PELI1.
Tissue specificityIsoform 1 and isoform 2 are ubiquitously expressed in all tissues examined, with isoform 1 being more strongly expressed than isoform 2.
Sequence similaritiesBelongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family. Pelle subfamily. Contains 1 protein kinase domain.
Post-translational modificationsAutophosphorylated or is transphosphorylated by IRAK4 following recruitment to the IL-1RI. In the case of isoform 1, this is linked to ubiquitination and degradation. Polyubiquitinated; after cell stimulation with IL-1-beta. Polyubiquitination occurs with polyubiquitin chains linked through 'Lys-63'.
Western blot - Anti-IRAK antibody [3F7] (ab119289)
Predicted band size : 77 kDa
Lane 1: Wild type HAP1 whole cell lysate (20 µg) Lane 2: IRAK1 knockout HAP1 whole cell lysate (20 µg) Lane 3: HeLa whole cell lysate (20 µg) Lane 4: Hek293 whole cell lysate (20 µg) Lanes 1 - 4: Merged signal (red and green). Green - ab119289 observed at 85 kDa. Red - loading control, ab181602, observed at 37 kDa.
ab119289 was shown to specifically react with IRAK1 when IRAK1 knockout samples were used. Wild-type and IRAK1 knockout samples were subjected to SDS-PAGE. Ab119289 and ab181602 (Rabbit anti GAPDH loading control) were incubated overnight at 4°C at 1/500 dilution and 1/10000 dilution respectively. Blots were developed with 800CW Goat anti-Mouse and 680CW Goat anti-Rabbit secondary antibodies at 1/10000 dilution for 1 hour at room temperature before imaging.