Structural analysis of 14-3-3 phosphopeptide complexes identifies a dual role for the nuclear export signal of 14-3-3 in ligand binding.
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Rittinger K, Budman J, Xu J, Volinia S, Cantley LC, Smerdon SJ, Gamblin SJ, Yaffe MB
Structural analysis of 14-3-3 phosphopeptide complexes identifies a dual role for the nuclear export signal of 14-3-3 in ligand binding.
Mol Cell. 1999 Aug;4(2):153-66.
- PubMed ID
- 10488331 [ View in PubMed]
- Abstract
We have solved the high-resolution X-ray structure of 14-3-3 bound to two different phosphoserine peptides, representing alternative substrate-binding motifs. These structures reveal an evolutionarily conserved network of peptide-protein interactions within all 14-3-3 isotypes, explain both binding motifs, and identify a novel intrachain phosphorylation-mediated loop structure in one of the peptides. A 14-3-3 mutation disrupting Raf signaling alters the ligand-binding cleft, selecting a different phosphopeptide-binding motif and different substrates than the wild-type protein. Many 14-3-3: peptide contacts involve a C-terminal amphipathic alpha helix containing a putative nuclear export signal, implicating this segment in both ligand and Crm1 binding. Structural homology between the 14-3-3 NES structure and those within I kappa B alpha and p53 reveals a conserved topology recognized by the Crm1 nuclear export machinery.