J. Biochem, 2004, Vol. 135, No. 4 479-485
© 2004 The Japanese Biochemical Society
BIOCHEMISTRY |
In Vitro Phosphorylation of Initiation Factor 2
(aIF2) from Hyperthermophilic Archaeon Pyrococcus horikoshii OT3
1 Laboratory of Biochemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581; and 2 Department of virus 3, Laboratory-5, National Institute of Infectious Diseases, Tokyo 208-0011
Eukaryotic initiation factor 2 (eIF2) is a heterotrimeric protein composed of 
, ß, and 
subunits, of which the subunit (eIF2) 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 (aIF2), three genes encoding , ß, and subunits of aIF2 from the hyperthermophilic archaeon Pyrococcus horikoshii OT3 were expressed in Escherichia coli cells, and the resulting proteins, aIF2, aIF2ß, and aIF2, were characterized with reference to the properties of eIF2. aIF2 preferentially interacts with aIF2, but does not interact with aIF2ß, which is consistent with data obtained with eIF2, of which eIF2 serves as a core subunit, interacting with eIF2 and eIF2ß. It was found that aIF2 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. 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, 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, like eIF2 in eukaryotes, plays a role in regulation of the protein synthesis in Archaea through phosphorylation and dephosphorylation.
* To whom correspondence should be addressed. Tel/Fax: +81-92-642-2853, E-mail: mkimura{at}agr.kyushu-u.ac.jp
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  P. A. Kirkland, M. A. Gil, I. M. Karadzic, and J. A. Maupin-Furlow Genetic and Proteomic Analyses of a Proteasome-Activating Nucleotidase A Mutant of the Haloarchaeon Haloferax volcanii J. Bacteriol., January 1, 2008; 190(1): 193 - 205. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Eichler and M. W. W. Adams Posttranslational Protein Modification in Archaea Microbiol. Mol. Biol. Rev., September 1, 2005; 69(3): 393 - 425. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Pedulla, R. Palermo, D. Hasenohrl, U. Blasi, P. Cammarano, and P. Londei The archaeal eIF2 homologue: functional properties of an ancient translation initiation factor Nucleic Acids Res., March 23, 2005; 33(6): 1804 - 1812. [Abstract] [Full Text] [PDF]
|
|