Interaction of 14-3-3 with a nonphosphorylated protein ligand, exoenzyme S of Pseudomonas aeruginosa. Biochemistry 1999 Apr 20;38(16):5216-21
Date
04/23/1999Pubmed ID
10213629DOI
10.1021/bi982492mScopus ID
2-s2.0-0033586783 (requires institutional sign-in at Scopus site) 128 CitationsAbstract
The 14-3-3 proteins are a family of conserved, dimeric proteins that interact with a diverse set of ligands, including molecules involved in cell cycle regulation and apoptosis. It is well-established that 14-3-3 binds to many ligands through phosphoserine motifs. Here we characterize the interaction of 14-3-3 with a nonphosphorylated protein ligand, the ADP-ribosyltransferase Exoenzyme S (ExoS) from Pseudomonas aeruginosa. By using affinity chromatography and surface plasmon resonance, we show that the zeta isoform of 14-3-3 (14-3-3zeta) can directly bind a catalytically active fragment of ExoS in vitro. The interaction between ExoS and 14-3-3zeta is of high affinity, with an equilibrium dissociation constant of 7 nM. ExoS lacks any known 14-3-3 binding motif, but to address the possibility that 14-3-3 binds a noncanonical phosphoserine site, we assayed ExoS for protein-bound phosphate by using mass spectrometry. No detectable phosphoproteins were found. A phosphopeptide ligand of 14-3-3, pS-Raf-259, was capable of inhibiting the binding of 14-3-3 to ExoS, suggesting that phosphorylated and nonphosphorylated ligands may share a common binding site, the conserved amphipathic groove. It is conceivable that 14-3-3 proteins may bind both phosphoserine and nonphosphoserine ligands in cells, possibly allowing kinase-dependent as well as kinase-independent regulation of 14-3-3 binding.
Author List
Masters SC, Pederson KJ, Zhang L, Barbieri JT, Fu HAuthor
Joseph T. Barbieri PhD Professor in the Microbiology and Immunology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
14-3-3 ProteinsADP Ribose Transferases
Amino Acid Sequence
Bacterial Toxins
Binding, Competitive
Enzyme Inhibitors
Ligands
Models, Molecular
Molecular Sequence Data
Peptides
Phosphorylation
Protein Binding
Protein Isoforms
Proteins
Pseudomonas aeruginosa
Recombinant Proteins
Tyrosine 3-Monooxygenase