Regulation of IRAK-4 kinase activity via autophosphorylation within its activation loop
| Autor: | Bruce Jaffee, Ping Li, Anlai Wang, Yajun Xu, Terri Addona, Zhi Li, Timothy D. Ocain, Hong Cheng, Hasmik Keshishian, Thomas F. Parsons, Chafen Lu, Marion Dorsch, Erik Dahlstrand |
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| Rok vydání: | 2007 |
| Předmět: |
Molecular Sequence Data
Biophysics Mitogen-activated protein kinase kinase Kidney Biochemistry Cell Line Feedback MAP2K7 Structure-Activity Relationship Humans Amino Acid Sequence Kinase activity Molecular Biology MAPK14 Binding Sites biology MAP kinase kinase kinase Chemistry Cyclin-dependent kinase 2 Autophosphorylation Cell Biology Molecular biology Cell biology Enzyme Activation Interleukin-1 Receptor-Associated Kinases biology.protein Cyclin-dependent kinase 9 Protein Binding Signal Transduction |
| Zdroj: | Biochemical and Biophysical Research Communications. 352:609-616 |
| ISSN: | 0006-291X |
| DOI: | 10.1016/j.bbrc.2006.11.068 |
| Popis: | Interleukin-1 stimulation leads to the recruitment of MyD88, interleukin-1 receptor-associated kinase 1 (IRAK-1) and interleukin-1 receptor-associated kinase 4 (IRAK-4) to the IL-1 receptor. The formation of the IL-1 receptor complex triggers a series of IRAK-1 autophosphorylations, which result in activation. IRAK-4 is upstream of IRAK-1 and may act as IRAK-1 kinase to transmit the signal. To date, there is no upstream kinase reported for IRAK-4; the activation mechanism of IRAK-4 remains poorly understood. Here, for the first time, we report three autophosphorylation sites that are responsible for IRAK-4 kinase activity. LC–MS/MS analysis has identified phosphorylations at T342, T345, and S346, which reside within the activation loop. Site-directed mutants at these positions exhibit significant reductions in the catalytic activity of IRAK-4 (T342A: 57%; T345A: 66%; S346A: 50%). The absence of phosphorylation in kinase-dead IRAK-4 indicates that phosphorylations in the activation loop result from autophosphorylation rather than from phosphorylation by an upstream kinase. Finally, we demonstrate that autophosphorylation is an intramolecular event as wild-type IRAK-4 failed to transphosphorylate kinase-inactive IRAK-4. The present data indicate that the kinase activity of IRAK-4 is dependent on the autophosphorylations at T342, T345, and S346 in the activation loop. |
| Databáze: | OpenAIRE |
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