Binding preference of eIF4E for 4E-binding protein isoform and function of eIF4E N-terminal flexible region for interaction, studied by SPR analysis.
To investigate the binding preference of eIF4E for the three eIF4E-binding isoforms (4E-BP1-3) and the function of N-terminal flexible region of eIF4E for their interactions, the binding parameters of recombinant full-length and N-terminal residues-deleted eIF4Es with 4E-BP1-3 were investigated by the surface plasmon resonance (SPR) analysis. Consequently, it was clarified that 4E-BP2 exhibits the highest binding affinity for both m7GTP-bound and -unbound full-length eIF4Es when compared with 4E-BP1 and 4E-BP3. This is primarily due to the difference among their dissociation rates, because their association rates are almost the same. Interestingly, the deletion of the 33 N-terminal residues of eIF4E increased its binding affinities for 4E-BP1 and 4E-BP2 markedly, whereas such a change was not observed by at least the N-terminal deletion up to 26 residues. In contrast, the binding parameters of 4E-BP3 were hardly influenced by N-terminal deletion up to 33 residues. From the comparison of the amino acid sequences of 4E-BP1-3, the present result indicates the importance of N-terminal flexible region of eIF4E for the suppressive binding with 4E-BP1 and 2, together with the possible contribution of N-terminal sequence of 4E-BP isoform to the regulative binding to eIF4E.
Abiko
Fumi
F
Department of Physical Chemistry, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
Tomoo
Koji
K
Mizuno
Atsuo
A
Morino
Shigenobu
S
Imataka
Hiroaki
H
Ishida
Toshimasa
T
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry*; D018797:Cell Cycle Proteins; D039561:Eukaryotic Initiation Factor-4E / Q000737:chemistry* / Q000235:genetics; D039642:Eukaryotic Initiation Factors / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000737:chemistry*; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry; D020349:Surface Plasmon Resonance
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C087000:EIF4EBP1 protein, human; C104151:EIF4EBP2 protein, human; C112661:EIF4EBP3 protein, human; D039561:Eukaryotic Initiation Factor-4E; D039642:Eukaryotic Initiation Factors; D010750:Phosphoproteins; D020033:Protein Isoforms