Enhancement of helicase activity and increase of eIF-4E phosphorylation in ornithine decarboxylase-overproducing cells.
In mouse FM3A ornithine decarboxylase (ODC) overproducing cells (EXOD-1), the amount of ODC protein was approximately 100-fold that of normal cells. Since it is well known that the translational efficiency of ODC mRNA is very low and that eIF-4E is a limiting factor for the mRNA recognition and the scanning of 40 S ribosomal subunits, we measured the amount and phosphorylation of eIF-4E in EXOD-1 cells. An increase in the phosphorylation of eIF-4E, its association with p220 protein, and an enhancement of RNA helicase activity were observed in the cells. These results support the hypothesis that phosphorylation of eIF-4E enhances RNA helicase activity through eIF-4F (4A, 4E, and p220) complex formation.
Shimogori
T
T
Faculty of Pharmaceutical Sciences, Chiba University, Japan.
Suzuki
T
T
Kashiwagi
K
K
Kakinuma
Y
Y
Igarashi
K
K
D000818:Animals; D001483:Base Sequence; D004265:DNA Helicases / Q000378:metabolism*; D039561:Eukaryotic Initiation Factor-4E; D015870:Gene Expression; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011073:Polyamines / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D012265:Ribonucleotides / Q000737:chemistry
D039561:Eukaryotic Initiation Factor-4E; D046911:Macromolecular Substances; D010446:Peptide Fragments; D010448:Peptide Initiation Factors; D011073:Polyamines; D012333:RNA, Messenger; D012265:Ribonucleotides; C069883:initiation factor 4F component p220; D004265:DNA Helicases; D009955:Ornithine Decarboxylase