Journal article

Publication year: 2004

Pages: 5227-5236

Journal: Journal of Biological Chemistry

Volume number: 279

Issue number: 7

ISSN: 0021-9258

Open access status: Hybrid

DOI Link: https://doi.org/10.1074/jbc.M309251200

Publisher: Elsevier

Abstract: 
The interleukin-1 receptor-associated kinase 1 (IRAK-1) is an important adapter in the signaling complex of the Toll/interleukin-1 (IL-1) receptor family. Formation of the signaling IL-1 receptor complex results in the activation and hyperphosphorylation of IRAK-1, which leads to a pronounced shift of its apparent molecular mass in gel electrophoresis. Presently, the individual residues phosphorylated in IRAK-1 and the consequences for IRAK-1 function are unknown. We define sequential phosphorylation steps in IRAK-1, which are, in vitro, autophosphorylation. First, IRAK-1 is phosphorylated at Thr(209). By fluorescence energy transfer experiments, we demonstrate that Thr209 phosphorylation results in a conformational change of the kinase domain, permitting further phosphorylations to take place. Substitution of Thr209 by alanine results in a kinase-inactive IRAK-1. Second, Thr(387) in the activation loop is phosphorylated, leading to full enzymatic activity. Third, IRAK-1 autophosphorylates several times in the proline-, serine-, and threonine-rich ProST region between the N-terminal death domain and kinase domain. Hyperphosphorylation of this region leads to dissociation of IRAK-1 from the upstream adapters MyD88 and Tollip but leaves its interaction with the downstream adapter TRAF6 unaffected. This identifies IRAK-1 as a novel type of adapter protein, which employs its own kinase activity to introduce negative charges adjacent to the protein interaction domain, which anchors IRAK-1 at the active receptor complex. Thus, IRAK-1 regulates its own availability as an adapter molecule by sequential autophosphorylation.

Harvard Citation style: Kollewe, C., Mackensen, A., Neumann, D., Knop, J., Cao, P., Li, S., et al. (2004) Sequential autophosphorylation steps in the interleukin-1 receptor-associated kinase-1 regulate its availability as an adapter in interleukin-1 signaling, Journal of Biological Chemistry, 279(7), pp. 5227-5236. https://doi.org/10.1074/jbc.M309251200

APA Citation style: Kollewe, C., Mackensen, A., Neumann, D., Knop, J., Cao, P., Li, S., Wesche, H., & Martin, M. (2004). Sequential autophosphorylation steps in the interleukin-1 receptor-associated kinase-1 regulate its availability as an adapter in interleukin-1 signaling. Journal of Biological Chemistry. 279(7), 5227-5236. https://doi.org/10.1074/jbc.M309251200