ERK1/2 map kinase metabolic pathway is responsible for phosphorylation of translation initiation factor eIF4E during in vitro maturation of pig oocytes.
Eukaryotic initiation factor 4E (eIF4E) plays an important role in mRNA translation by binding the 5'-cap structure of the mRNA and facilitating the recruitment to the mRNA of other translation factors and the 40S ribosomal subunit. eIF4E undergoes regulated phosphorylation on Ser-209 and this phosphorylation is believed to be important for its binding to mRNA and to other initiation factors. The findings showing that the translation initiation factor eIF4E becomes gradually phosphorylated during in vitro maturation (IVM) of pig oocytes with a maximum in metaphase II (M II) stage oocytes have been documented by us recently (Ellederova et al., 2006). The aim of this work was to study in details the metabolic pathways involved in this process. Using inhibitors of cyclin-dependent kinases, Butyrolactone I (BL I) and protein phosphatases, okadaic acid (OA) we show that ERK1/2 MAP kinase pathway is involved in this phosphorylation. We also demonstrate that activation and phosphorylation of ERK1/2 MAP kinase and eIF4E is associated with the activating phosphorylation of Mnk1 kinase, one of the two main kinases phosphorylating eIF4E in somatic cells.
Ellederová
Zdenka
Z
Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Libechov, Czech Republic.
Cais
Ondrej
O
Susor
Andrej
A
Uhlírová
Katka
K
Kovárová
Hana
H
Jelínková
Lucie
L
Tomek
Wolfgang
W
Kubelka
Michal
M
D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D007525:Isoelectric Focusing; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation; D013552:Swine
D004791:Enzyme Inhibitors; D039561:Eukaryotic Initiation Factor-4E; D048052:Mitogen-Activated Protein Kinase 3