The 14-3-3 protein binds its target proteins with a common site located towards the C-terminus.
The 14-3-3 protein family binds a variety of proteins in cell-signaling pathways, but the structural elements necessary for the ligand binding are poorly understood. Here we demonstrate that the 'box-1' region, which spans residues 171-213 in the eta-isoform and was previously identified as the binding site of 14-3-3 to the phosphorylated tryptophan hydroxylase, plays a critical role in the interaction with many target proteins. Using a series of truncated 14-3-3 mutants, we show that the mutant 167-213 carrying box-1 binds bacurovirus-expressed Raf-1 and Bcr protein kinases to the similar extent as the full-length 14-3-3 in a phosphorylation-dependent manner, while the mutants lacking this region abolish the binding activity. Furthermore, the box-1 region also appears essential for binding of 14-3-3 to more than 40 phosphoproteins found in the brainstem extract. These results suggest that the box-1 region, consisting of helices 7 and 8 in the tertiary structure, is a common structural element whereby the 14-3-3 protein binds many, if not all, target proteins.
Ichimura
T
T
Department of Biochemistry, Faculty of Science, Niigata University, Japan.
Ito
M
M
Itagaki
C
C
Takahashi
M
M
Horigome
T
T
Omata
S
S
Ohno
S
S
Isobe
T
T
D048948:14-3-3 Proteins; D000818:Animals; D001933:Brain Stem / Q000378:metabolism*; D002457:Cell Extracts; D006801:Humans; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051562:Proto-Oncogene Proteins c-bcr; D019908:Proto-Oncogene Proteins c-raf; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017384:Sequence Deletion; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; D002457:Cell Extracts; D010750:Phosphoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D014446:Tyrosine 3-Monooxygenase; D011505:Protein-Tyrosine Kinases; C496613:BCR protein, human; D017346:Protein Serine-Threonine Kinases; D051562:Proto-Oncogene Proteins c-bcr; D019908:Proto-Oncogene Proteins c-raf