Modulation of the Eukaryotic Initiation Factor 2 α-Subunit Kinase PERK by Tyrosine Phosphorylation
| Autor: | Shuo Wang, David Ron, Hong Qing Gao, Shirin Kazemi, Qiaozhu Su, Antonis E. Koromilas, Heather P. Harding |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
endocrine system
Eukaryotic Initiation Factor-2 Immunoblotting Endoplasmic Reticulum Biochemistry Mice eIF-2 Kinase chemistry.chemical_compound Cell Line Tumor Chlorocebus aethiops Serine Animals Humans Immunoprecipitation Phosphorylation Protein kinase A Molecular Biology Autophosphorylation Dual-specificity kinase Tyrosine phosphorylation Cell Biology Molecular biology Protein kinase domain chemistry Protein Biosynthesis COS Cells Mutation Mutagenesis Site-Directed Unfolded protein response Tyrosine Electrophoresis Polyacrylamide Gel Tyrosine kinase Plasmids |
| Zdroj: | Journal of Biological Chemistry. 283:469-475 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m704612200 |
| Popis: | The endoplasmic reticulum (ER)-resident protein kinase PERK attenuates protein synthesis in response to ER stress through the phosphorylation of translation initiation factor eIF2alpha at serine 51. ER stress induces PERK autophosphorylation at several serine/threonine residues, a process that is required for kinase activation and phosphorylation of eIF2alpha. Herein, we demonstrate that PERK also possesses tyrosine kinase activity. Specifically, we show that PERK is capable of autophosphorylating on tyrosine residues in vitro and in vivo. We further show that tyrosine 615, which is embedded in a highly conserved region of the kinase domain of PERK, is essential for autocatalytic activity. That is, mutation of Tyr-615 to phenylalanine compromises the autophosphorylation capacity of PERK and the phosphorylation of eIF2alpha in vitro and in vivo. The Y615F mutation also impairs the ability of PERK to induce translation of ATF4. Immunoblot analyses with a phosphospecific antibody confirm the phosphorylation of PERK at Tyr-615 both in vitro and in vivo. Thus, our data classify PERK as a dual specificity kinase whose regulation by tyrosine phosphorylation contributes to its optimal activation in response to ER stress. |
| Databáze: | OpenAIRE |
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