Characterizing the interaction of the mammalian eIF4E-related protein 4EHP with 4E-BP1.
Eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) represses translation initiation by binding to eukaryotic initiation factor 4E (eIF4E). 4E-BP1 also binds to the eIF4E homologous protein (4EHP). We show that eIF4E-binding mutants of 4E-BP1 (Y54A and L59A) fail to form heterodimeric complexes with wild-type 4EHP. In addition, the W95A mutant of 4EHP, similar to a homologous mutation in eIF4E, inhibits its binding to wild-type 4E-BP1. Interestingly, 4EHP over-expression instigates a negative feedback loop that inhibits upstream signaling to 4E-BP1 and ribosomal protein S6 kinase 1 (S6K1) whereas the 4E-BP1-binding-deficient mutant of 4EHP(W95A) was unable to trigger this feedback loop. Thus, the interaction of 4EHP with 4E-BP1 is necessary for this observed impaired signaling to 4E-BP1 and S6K1.
Tee
Andrew R
AR
Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
Tee
Jennifer A
JA
Blenis
John
J
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins; D002460:Cell Line; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics / Q000378:metabolism*; D039642:Eukaryotic Initiation Factors; D025461:Feedback, Physiological; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D051379:Mice; D020125:Mutation, Missense; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D039381:RNA Cap-Binding Proteins / Q000235:genetics / Q000378:metabolism; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism; D014162:Transfection
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C112609:EIF4E2 protein, human; C087000:EIF4EBP1 protein, human; C499527:Eif4ebp1 protein, mouse; D039561:Eukaryotic Initiation Factor-4E; D039642:Eukaryotic Initiation Factors; D007328:Insulin; D010448:Peptide Initiation Factors; D010750:Phosphoproteins; D039381:RNA Cap-Binding Proteins; C000597857:eIF4E2 protein, mouse; C069329:RPS6KA1 protein, human; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C512964:Rps6ka1 protein, mouse