In vivo inactivation of phosphotyrosine protein phosphatases by nitric oxide

Caselli, Anna; Chiarugi, Paola; Camici, Giovanni G.; Manao, Giampaolo; Ramponi, Giampietro

doi:10.1016/0014-5793(95)01120-4

Cited by 43 publications

(28 citation statements)

References 22 publications

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“…Extracellularly Generated Oxidative Stress-As already reported LMW-PTP is oxidized in vitro by H 2 O 2 and NO (11,12) in its catalytic site cysteines 12 and 17. To study if the generation of an oxidative stress in vivo could lead to LMW-PTP oxidation, thus influencing its catalytic activity, we have used the NIH3T3 fibroblast cell line overexpressing wtLMW-PTP.…”

Section: Regulation Of Lmw-ptp Activity On Pdgf Receptor Duringmentioning

confidence: 73%

“…The PTP activity of wtLMW-PTP-expressing cells is strongly inhibited by H 2 O 2 treatment, confirming the results obtained with phosphorylated PDGF-R and p190Rho-GAP. Caselli et al (11,12) have demonstrated that LMW-PTP is oxidized in vitro by both H 2 O 2 and NO and is able to rescue its catalytic activity after treatment with reducing agents. It is interesting to note that further treatment with catalase for 10 min (to remove H 2 O 2 ) led to a complete recovery of LMW-PTP activity ( Fig.…”

Section: Regulation Of Lmw-ptp Activity On Pdgf Receptor Duringmentioning

confidence: 99%

“…Van Etten et al (26) have demonstrated that LMW-PTP has two reactive cysteines in the catalytic site with a low pK a (at pH 7.52 and 9.05 for iodoacetamide). Caselli et al (11,12) have demonstrated that H 2 O 2 and NO lead to the specific oxidation of Cys-12 and Cys-17 in the catalytic pocket of LMW-PTP. In addition the active site cysteines of LMW-PTP, as in other PTPs, are specifically targeted by the sulfhydryl-modifying reagent iodoacetic acid (25,26).…”

Section: Regulation Of Lmw-ptp Activity On Pdgf Receptor Duringmentioning

confidence: 99%

“…Caselli et al (11,12) have demonstrated that in vitro LMW-PTP is oxidized and inactivated by NO or H 2 O 2 and that P i is able to protect the enzyme from oxidation. H 2 O 2 causes the oxidation of Cys-12 and Cys-17, the two vicinal cysteines in the catalytic pocket, as demonstrated by mass spectroscopy and radiolabeled tryptic fingerprint analysis.…”

mentioning

confidence: 99%

“…H 2 O 2 causes the oxidation of Cys-12 and Cys-17, the two vicinal cysteines in the catalytic pocket, as demonstrated by mass spectroscopy and radiolabeled tryptic fingerprint analysis. Furthermore, Caselli et al (11,12) have demonstrated that H 2 O 2 oxidizes Cys-12 and Cys-17 to form a disulfide bond. Treatment of LMW-PTP with dithiothreitol restores its enzymatic activity.…”

mentioning

confidence: 99%

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Two Vicinal Cysteines Confer a Peculiar Redox Regulation to Low Molecular Weight Protein Tyrosine Phosphatase in Response to Platelet-derived Growth Factor Receptor Stimulation

Chiarugi

Fiaschi

Taddei

et al. 2001

Journal of Biological Chemistry

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175

154

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Low molecular weight protein tyrosine phosphatase (LMW-PTP) is an enzyme involved in platelet-derived growth factor (PDGF)-induced mitogenesis and cytoskeleton rearrangement because it is able to bind and dephosphorylate the activated receptor. LMW-PTP presents two cysteines in positions 12 and 17, both belonging to the catalytic pocket; this is a unique feature of LMW-PTP among all protein tyrosine phosphatases. Our previous results demonstrated that in vitro LMW-PTP is oxidized by either H 2 O 2 or nitric oxide with the formation of a disulfide bond between Cys-12 and Cys-17. This oxidation leads to reversible enzyme inactivation because treatment with reductants permits catalytic activity rescue. In the present study we investigated the in vivo inactivation of LMW-PTP by either extracellularly or intracellularly generated H 2 O 2 , evaluating its action directly on its natural substrate, PDGF receptor. LMW-PTP is oxidized and inactivated by exogenous oxidative stress and recovers its activity after oxidant removal. LMW-PTP is oxidized also during PDGF signaling, very likely upon PDGF-induced H 2 O 2 production, and recovers its activity within 40 min. Our results strongly suggest that reversibility of in vivo LMW-PTP oxidation is glutathione-dependent. In addition, we propose an intriguing and peculiar role of Cys-17 in the formation of a S-S intramolecular bond, which protects the catalytic Cys-12 from further and irreversible oxidation. On the basis of our results we propose that the presence of an additional cysteine near the catalytic cysteine could confer to LMW-PTP the ability to rapidly recover its activity and finely regulate PDGF receptor activation during both extracellularly and intracellularly generated oxidative stress.Protein tyrosine phosphorylation plays a key role in the regulation of many cellular processes in eukaryotes such as cellular metabolism, proliferation, differentiation, and oncogenic transformation (1). Accumulating evidence indicates that the contribution of phosphotyrosine protein phosphatases (PTPs) 1 to the control of the cell phosphorylation state is as relevant as that of phosphotyrosine protein kinases. The PTP superfamily is composed of over 70 enzymes that, despite very limited sequence similarity, share a common CX 5 R active site motif and an identical catalytic mechanism. On the basis of their function, structure, and sequence, PTPs can be classified in four main families: 1) tyrosine-specific phosphatases, 2) VH1-like dual specificity PTPs, 3) the cdc25 phosphatases, and 4) the low molecular weight phosphatase (2).The low molecular weight protein tyrosine phosphatase (LMW-PTP) is an 18-kDa enzyme that is expressed in many mammalian tissues (3). Our previous studies on the molecular biology of LMW-PTP in NIH3T3 cells demonstrated a well defined role of this enzyme in platelet-derived growth factor (PDGF)-induced mitogenesis. The most relevant phenotypic effect of LMW-PTP overexpression is a strong reduction of the cell growth rate in response to PDGF stimulation. We ...

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Section: Regulation Of Lmw-ptp Activity On Pdgf Receptor Duringmentioning

confidence: 73%

Section: Regulation Of Lmw-ptp Activity On Pdgf Receptor Duringmentioning

confidence: 99%

Section: Regulation Of Lmw-ptp Activity On Pdgf Receptor Duringmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Two Vicinal Cysteines Confer a Peculiar Redox Regulation to Low Molecular Weight Protein Tyrosine Phosphatase in Response to Platelet-derived Growth Factor Receptor Stimulation

Chiarugi

Fiaschi

Taddei

et al. 2001

Journal of Biological Chemistry

Self Cite

175

154

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Protein-tyrosine phosphatases: Structure, mechanism, and inhibitor discovery

1998

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Protein–tyrosine kinases (PTKs) and their associated signaling pathways are crucial for the regulation of numerous cell functions including growth, mitogenesis, motility, cell–cell interactions, metabolism, gene transcription, and the immune response. Since tyrosine phosphorylation is reversible and dynamic in vivo, the phosphorylation states of proteins are governed by the opposing actions of PTKs and protein–tyrosine phosphatases (PTPs). In this light, both PTKs and PTPs play equally important roles in signal transduction in eukaryotic cells, and comprehension of mechanisms behind the reversible pTyr‐dependent modulation of protein function and cell physiology must necessarily encompass the characterization of PTPs as well as PTKs. In spite of the large number of PTPs identified to date and the emerging role played by PTPs in disease, a detailed understanding of the role played by PTPs in signaling pathways has been hampered by the absence of PTP‐specific agents. Such PTP‐specific inhibitors could potentially serve as useful tools in determining the physiological significance of protein tyrosine phosphorylation in complex cellular signal transduction pathways and may constitute valuable therapeutics in the treatment of several human diseases. The goal of this review is therefore to summarize current understandings of PTP structure and mechanism of catalysis and the relationship of these to PTP inhibitor development. The review is organized such that enzyme structure is covered first, followed by mechanisms of catalysis then PTP inhibitor development. In discussing PTP inhibitor development, nonspecific inhibitors and those obtained by screening methods are initially presented with the focus then shifting to inhibitors that utilize a more structure‐based rationale. © 1998 John Wiley & Sons, Inc. Biopoly 47: 225–241, 1998

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