In vitro phosphorylation of initiation factor 2 alpha (aIF2 alpha) from hyperthermophilic archaeon Pyrococcus horikoshii OT3
| Autor: | Akiko Ohsawa, Maino Tahara, Sakura Saito, Makoto Kimura |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Protein subunit
Archaeal Proteins Recombinant Fusion Proteins Eukaryotic Initiation Factor-2 Genetic Vectors Molecular Sequence Data Alpha (ethology) Gene Expression Transfection Biochemistry Polymerase Chain Reaction Pyrococcus horikoshii eIF-2 Kinase Peptide Initiation Factors Heterotrimeric G protein Protein Interaction Mapping Escherichia coli Initiation factor Humans Amino Acid Sequence Phosphorylation Molecular Biology G alpha subunit eIF2 biology Sequence Homology Amino Acid General Medicine biology.organism_classification Protein Subunits Mutation Mutagenesis Site-Directed Electrophoresis Polyacrylamide Gel Protein Kinases |
| Zdroj: | Journal of biochemistry. 135(4) |
| ISSN: | 0021-924X |
| Popis: | Eukaryotic initiation factor 2 (eIF2) is a heterotrimeric protein composed of alpha, beta, and gamma subunits, of which the alpha subunit (eIF2 alpha) plays a crucial role in regulation of protein synthesis through phosphorylation at Ser51. All three subunit genes are conserved in Archaea. To examine the properties of archaeal initiation factor 2 alpha (aIF2 alpha), three genes encoding alpha, beta, and gamma subunits of aIF2 from the hyperthermophilic archaeon Pyrococcus horikoshii OT3 were expressed in Escherichia coli cells, and the resulting proteins, aIF2 alpha, aIF2 beta, and aIF2 gamma, were characterized with reference to the properties of eIF2. aIF2 alpha preferentially interacts with aIF2 gamma, but does not interact with aIF2 beta, which is consistent with data obtained with eIF2, of which eIF2 gamma serves as a core subunit, interacting with eIF2 alpha and eIF2 beta. It was found that aIF2 alpha was, albeit to a lower degree, phosphorylated by double-stranded RNA-dependent protein kinase (hPKR) from human, and a primary target site was suggested to be Ser48 within aIF2 alpha. This finding led us to the search for a putative aIF2 specific kinase gene (PH0512) in the P. horikoshii genome. The gene product Ph0512p unambiguously phosphorylated aIF2 alpha, and Ser48, as in the phosphorylation by hPKR, was suggested to be a target amino acid residue for the PKR homologue Ph0152p in P. horikoshii. These findings suggest that aIF2 alpha, like eIF2 alpha in eukaryotes, plays a role in regulation of the protein synthesis in Archaea through phosphorylation and dephosphorylation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|