Publications

• A structural expose of noncanonical molecular reactivity within the protein tyrosine phosphatase WPD loop.

  Wang H., Perera L., Jork N., Zong G., Riley A.M., Potter B.V.L., Jessen H.J., Shears S.B.

  Structural snapshots of protein/ligand complexes are a prerequisite for gaining atomic level insight into enzymatic reaction mechanisms. An important group of enzymes has been deprived of this analytical privilege: members of the protein tyrosine phosphatase (PTP) superfamily with catalytic WPD-lo ... >> More

  Structural snapshots of protein/ligand complexes are a prerequisite for gaining atomic level insight into enzymatic reaction mechanisms. An important group of enzymes has been deprived of this analytical privilege: members of the protein tyrosine phosphatase (PTP) superfamily with catalytic WPD-loops lacking the indispensable general-acid/base within a tryptophan-proline-aspartate/glutamate context. Here, we provide the ligand/enzyme crystal complexes for one such PTP outlier: Arabidopsis thaliana Plant and Fungi Atypical Dual Specificity Phosphatase 1 (AtPFA-DSP1), herein unveiled as a regioselective and efficient phosphatase towards inositol pyrophosphate (PP-InsP) signaling molecules. Although the WPD loop is missing its canonical tripeptide motif, this structural element contributes to catalysis by assisting PP-InsP delivery into the catalytic pocket, for a choreographed exchange with phosphate reaction product. Subsequently, an intramolecular proton donation by PP-InsP substrate is posited to substitute functionally for the absent aspartate/glutamate general-acid. Overall, we expand mechanistic insight into adaptability of the conserved PTP structural elements. << Less

  Nat. Commun. 13:2231-2231(2022) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Arabidopsis PFA-DSP-Type Phosphohydrolases Target Specific Inositol Pyrophosphate Messengers.

  Gaugler P., Schneider R., Liu G., Qiu D., Weber J., Schmid J., Jork N., Haener M., Ritter K., Fernandez-Rebollo N., Giehl R.F.H., Trung M.N., Yadav R., Fiedler D., Gaugler V., Jessen H.J., Schaaf G., Laha D.

  Inositol pyrophosphates are signaling molecules containing at least one phosphoanhydride bond that regulate a wide range of cellular processes in eukaryotes. With a cyclic array of phosphate esters and diphosphate groups around <i>myo</i>-inositol, these molecular messengers possess the highest ch ... >> More

  Inositol pyrophosphates are signaling molecules containing at least one phosphoanhydride bond that regulate a wide range of cellular processes in eukaryotes. With a cyclic array of phosphate esters and diphosphate groups around <i>myo</i>-inositol, these molecular messengers possess the highest charge density found in nature. Recent work deciphering inositol pyrophosphate biosynthesis in <i>Arabidopsis</i> revealed important functions of these messengers in nutrient sensing, hormone signaling, and plant immunity. However, despite the rapid hydrolysis of these molecules in plant extracts, very little is known about the molecular identity of the phosphohydrolases that convert these messengers back to their inositol polyphosphate precursors. Here, we investigate whether <i>Arabidopsis</i> Plant and Fungi Atypical Dual Specificity Phosphatases (PFA-DSP1-5) catalyze inositol pyrophosphate phosphohydrolase activity. We find that recombinant proteins of all five <i>Arabidopsis</i> PFA-DSP homologues display phosphohydrolase activity with a high specificity for the 5-β-phosphate of inositol pyrophosphates and only minor activity against the β-phosphates of 4-InsP₇ and 6-InsP₇. We further show that heterologous expression of <i>Arabidopsis</i> PFA-DSP1-5 rescues wortmannin sensitivity and deranged inositol pyrophosphate homeostasis caused by the deficiency of the PFA-DSP-type inositol pyrophosphate phosphohydrolase Siw14 in yeast. Heterologous expression in <i>Nicotiana benthamiana</i> leaves provided evidence that <i>Arabidopsis</i> PFA-DSP1 also displays 5-β-phosphate-specific inositol pyrophosphate phosphohydrolase activity <i>in planta</i>. Our findings lay the biochemical basis and provide the genetic tools to uncover the roles of inositol pyrophosphates in plant physiology and plant development. << Less

  Biochemistry 61:1213-1227(2022) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Activities, substrate specificity, and genetic interactions of fission yeast Siw14, a cysteinyl-phosphatase-type inositol pyrophosphatase.

  Sanchez A.M., Schwer B., Jork N., Jessen H.J., Shuman S.

  <h4>Importance</h4>The inositol pyrophosphate signaling molecule 1,5-IP₈ modulates fission yeast phosphate homeostasis via its action as an agonist of RNA 3'-processing and transcription termination. Cellular 1,5-IP₈ levels are determined by a balance between the activities o ... >> More

  <h4>Importance</h4>The inositol pyrophosphate signaling molecule 1,5-IP₈ modulates fission yeast phosphate homeostasis via its action as an agonist of RNA 3'-processing and transcription termination. Cellular 1,5-IP₈ levels are determined by a balance between the activities of the inositol polyphosphate kinase Asp1 and several inositol pyrophosphatase enzymes. Here, we characterize <i>Schizosaccharomyces pombe</i> Siw14 (SpSiw14) as a cysteinyl-phosphatase-family pyrophosphatase enzyme capable of hydrolyzing the phosphoanhydride substrates inorganic pyrophosphate, inorganic polyphosphate, and inositol pyrophosphates 5-IP₇, 1-IP₇, and 1,5-IP₈. Genetic analyses implicate SpSiw14 in 1,5-IP₈ catabolism <i>in vivo</i>, insofar as: loss of SpSiw14 activity is lethal in the absence of the Nudix-type inositol pyrophosphatase enzyme Aps1; and <i>siw14</i>∆ <i>aps1</i>∆ lethality depends on synthesis of 1,5-IP₈ by the Asp1 kinase. Suppression of <i>siw14</i>∆ <i>aps1</i>∆ lethality by loss-of-function mutations of 3'-processing/termination factors points to precocious transcription termination as the cause of 1,5-IP₈ toxicosis. << Less

  MBio 14:e0205623-e0205623(2023) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.