Structural Insights into the Enzymatic Mechanism of the Pathogenic MAPK Phosphothreonine Lyase

Abstract

The OspF family of phosphothreonine lyase, including SpvC from Salmonella, irreversibly inactivates the dual-phosphorylated host MAPKs (pT-X-pY) through beta elimination. We determined crystal structures of SpvC and its complex with a phosphopeptide substrate. SpvC adopts a unique fold of alpha/beta type. The disordered N terminus harbors a canonical D motif for MAPK substrate docking. The enzyme-substrate complex structure indicates that recognition of the phosphotyrosine followed by insertion of the threonine phosphate into an arginine pocket places the phosphothreonine into the enzyme active site. This requires the conformational flexibility of pT-X-pY, which suggests that p38 (pT-G-pY) is likely the preferred physiological substrate. Structure-based biochemical and enzymatic analysis allows us to propose a general acid/base mechanism for beta elimination reaction catalyzed by the phosphothreonine lyase. The mechanism described here provides a structural understanding of MAPK inactivation by a family of pathogenic effectors conserved in plant and animal systems and may also open a new route for biological catalysis.

Structural basis of rifampin inactivation by rifampin phosphotransferase

“…These results suggest that this conserved His residue also may function as a phosphate acceptor and donor in the phosphorylation of RIF. In addition, positively charged residues often function as catalytic bases to abstract a proton at the reaction centers of phosphatetransfer enzymes and other enzymes, including MAPK, phosphothreonine lyase, IMP dehydrogenase, pectate/pectin lyases, fumarate reductase, and L-aspartate oxidase (21)(22)(23), suggesting that Lys670 and Arg666 might be candidate residues for the catalytic bases of LmRPH.…”

Propofol attenuates intermittent hypoxia induced up-regulation of proinflammatory cytokines in microglia through inhibiting the activation of NF-Bκ/p38 MAPK signalling

“…Additionally, MAPKs, including the extracellular signal-regulated kinase (ERK), the c-jun NH2-terminal kinases (JNK) and the p38 MAPK, can be phosphorylated and then positively regulate the expression of inflammatory genes and cytokines [31,35]. Among these, p38 MAPK acts as a crucial regulator for the production of NF-κB-mediated proinflammatory cytokines and other mediators [15].…”

Consistent activation of the β-catenin pathway by Salmonella type-three secretion effector protein AvrA in chronically infected intestine

“…The Wnt and Akt pathways interact to control ␤-catenin nuclear localization and transcriptional activity in epithelial homoeostasis (16). It is known that AvrA influences eukaryotic cell pathways via proteins including NF-B, JNK, and ␤-catenin (51,56). Many proteins coordinate distinct signaling pathways in cells by having multiple functions.…”