The eukaryotic mRNA decapping protein Dcp1 interacts physically and functionally with the eIF4F translation initiation complex.
Dcp1 plays a key role in the mRNA decay process in Saccharomyces cerevisiae, cleaving off the 5' cap to leave an end susceptible to exonucleolytic degradation. The eukaryotic initiation factor complex eIF4F, which in yeast contains the core components eIF4E and eIF4G, uses the cap as a binding site, serving as an initial point of assembly for the translation apparatus, and also binds the poly(A) binding protein Pab1. We show that Dcp1 binds to eIF4G and Pab1 as free proteins, as well as to the complex eIF4E-eIF4G-Pab1. Dcp1 interacts with the N-terminal region of eIF4G but does not compete significantly with eIF4E or Pab1 for binding to eIF4G. Most importantly, eIF4G acts as a function-enhancing recruitment factor for Dcp1. However, eIF4E blocks this effect as a component of the high affinity cap-binding complex eIF4E-eIF4G. Indeed, cooperative enhancement of the eIF4E-cap interaction stabilizes yeast mRNAs in vivo. These data on interactions at the interface between translation and mRNA decay suggest how events at the 5' cap and 3' poly(A) tail might be coupled.
Vilela
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Posttranscriptional Control Group, Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology PO Box 88, Manchester M60 1QD, UK.
Velasco
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C
Ptushkina
M
M
McCarthy
J E
JE
D015153:Blotting, Western; D002847:Chromatography, Agarose; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004722:Endoribonucleases; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000378:metabolism; D039562:Eukaryotic Initiation Factor-4F; D039603:Eukaryotic Initiation Factor-4G; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008024:Ligands; D008954:Models, Biological; D009690:Nucleic Acid Conformation; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D039102:Poly(A)-Binding Proteins; D011233:Precipitin Tests; D011485:Protein Binding; D014176:Protein Biosynthesis; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D039381:RNA Cap-Binding Proteins; D012333:RNA, Messenger / Q000378:metabolism*; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013997:Time Factors; D014466:Ultraviolet Rays
D003432:Cross-Linking Reagents; D039562:Eukaryotic Initiation Factor-4F; D039603:Eukaryotic Initiation Factor-4G; D005656:Fungal Proteins; D008024:Ligands; D010448:Peptide Initiation Factors; D039102:Poly(A)-Binding Proteins; D039381:RNA Cap-Binding Proteins; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D006160:Guanosine Triphosphate; C100868:DCP1 protein, S cerevisiae; D004722:Endoribonucleases