title: 14-3-3zeta binds a phosphorylated Raf peptide and an unphosphorylated peptide via its conserved amphipathic groove.
abstract: 14-3-3 proteins bind a variety of molecules involved in signal transduction, cell cycle regulation and apoptosis. 14-3-3 binds ligands such as Raf-1 kinase and Bad by recognizing the phosphorylated consensus motif, RSXpSXP, but must bind unphosphorylated ligands, such as glycoprotein Ib and Pseudomonas aeruginosa exoenzyme S, via a different motif. Here we report the crystal structures of the zeta isoform of 14-3-3 in complex with two peptide ligands: a Raf-derived phosphopeptide (pS-Raf-259, LSQRQRSTpSTPNVHMV) and an unphosphorylated peptide derived from phage display (R18, PHCVPRDLSWLDLEANMCLP) that inhibits binding of exoenzyme S and Raf-1. The two peptides bind within a conserved amphipathic groove on the surface of 14-3-3 at overlapping but distinct sites. The phosphoserine of pS-Raf-259 engages a cluster of basic residues (Lys49, Arg56, Arg60, and Arg127), whereas R18 binds via the amphipathic sequence, WLDLE, with its two acidic groups coordinating the same basic cluster. 14-3-3 is dimeric, and its two peptide-binding grooves are arranged in an antiparallel fashion, 30 A apart. The ability of each groove to bind different peptide motifs suggests how 14-3-3 can act in signal transduction by inducing either homodimer or heterodimer formation in its target proteins.
authors.affiliation: Department of Biochemistry, University of Leicester, Leicester LE1 7RH, United Kingdom.
authors.forename: C
authors.initials: C
authors.lastname: Petosa
authors.forename: S C
authors.initials: SC
authors.lastname: Masters
authors.forename: L A
authors.initials: LA
authors.lastname: Bankston
authors.forename: J
authors.initials: J
authors.lastname: Pohl
authors.forename: B
authors.initials: B
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Fu
authors.forename: R C
authors.initials: RC
authors.lastname: Liddington
mesh_terms: D048948:14-3-3 Proteins; D036002:ADP Ribose Transferases; D000595:Amino Acid Sequence; D000818:Animals; D001427:Bacterial Toxins; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D018360:Crystallography, X-Ray; D019281:Dimerization; D004791:Enzyme Inhibitors / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011487:Protein Conformation; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism*; D011550:Pseudomonas aeruginosa; D015398:Signal Transduction; D014446:Tyrosine 3-Monooxygenase; D014982:Xenopus laevis; D051025:bcl-Associated Death Protein
chemical_list: D048948:14-3-3 Proteins; D001427:Bacterial Toxins; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D019038:Platelet Glycoprotein GPIb-IX Complex; D011506:Proteins; D051025:bcl-Associated Death Protein; D010768:Phosphoserine; D014446:Tyrosine 3-Monooxygenase; D036002:ADP Ribose Transferases; D011065:Poly(ADP-ribose) Polymerases; C444820:exoenzyme S; D019908:Proto-Oncogene Proteins c-raf