Phosphatase activity characterization on the surface of intact bloodstream forms of<i>Trypanosoma brucei</i>

Fernandes, Eliana; Granjeiro, José Mauro; Taga, EulÃ¡zio Mikio; Meyer-Fernandes, J.R.; Aoyama, Hiroshi

doi:10.1016/s0378-1097(03)00091-0

Cited by 22 publications

(17 citation statements)

References 32 publications

(42 reference statements)

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“…In fact, cells respond to internal and external stimuli through integrated networks of intracellular signaling pathways that act via cascades of sequential phosphorylation or dephosphorylation reactions which are governed by the action of PK and PPs, respectively (Hooft van Huijsduijnen et al, 2002;Tonks, 2005). PPs have been classified by structure and substrate specificity into protein serine/threonine phosphatases (PSTPs) and protein tyrosine phosphatases (PTPs) (Aoyama et al, 2003;Gee and Mansuy, 2005). In general, PTPs control fundamental physiological processes such as cell growth and differentiation, cell cycle, metabolism, immune response and cytoskeletal function.…”

Section: Protein Phosphatasesmentioning

confidence: 99%

“…Although PTPs have conserved catalytic domains and share a common mechanism of action, substrate specificity of individual PTPs may display substantial specificity, thus resulting in these enzymes to regulate highly specialized and often fundamentally important processes. The PTP family shares a strictly conserved active site comprising the "P-loop" residues (H/V)C(X) 5 R(S/T) and a conserved acidic residue (Denu et al, 1996;Fauman et al, 1996;Zhang 2003;Aoyama et al, 2003). In all structurally characterized PTPs to date, the threedimensional structure of active-site components is also highly conserved suggesting a common catalytic mechanism.…”

Section: Mechanisms Of Ptp Catalysismentioning

confidence: 99%

“…In the first step, the phosphoryl group from the substrate is transferred to the nucleophilic cysteine, forming a phosphoenzyme intermediate. In the second step, this intermediate is hydrolyzed, leading to the regeneration of the enzyme and the release of an inorganic phosphate (Aoyama et al, 2003;Zhang, 1997). Although this two-step mechanism is well-established, some mechanistic aspects still need to be clarified, such as regulatory and inhibitory mechanisms.…”

Section: Mechanisms Of Ptp Catalysismentioning

confidence: 99%

“…Acid phosphatases (EC 3.1.3.2), enzymes that catalyze the hydrolysis of a wide range of orthophosphate monoesters, are largely distributed in nature and have been studied in numerous organisms and tissues (Granjeiro et al, 1997;Ferreira et al, 1998aFerreira et al, , 1998bGranjeiro et al, 1999;Fernandes et al, 2003;Jonsson et al, 2007). The enzyme found in mammalian tissues occurs in multiple forms that differ in regard to molecular mass, substrate specificity and sensitivity to inhibitors (Granjeiro et al, 1997).…”

Section: Acid Phosphatase 341 Signaling Featuresmentioning

confidence: 99%

“…PPs are subdivided into two major families, with regard to their physiological substrates: protein tyrosine phosphatases and serine/threonine phosphatases. In particular, tyrosine phosphorylation of key proteins is a critical event in the regulation of intracellular signaling pathways (Aoyama et al, 2003;Gee and Mansuy, 2004;Souza et al, 2009). There is strong evidence pointing that low SHP-1 PTP activity is associated with a high proliferation rate and an increased risk of recurrence after radical prostatectomy for localized prostate cancer (Tassidis et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Prostate Cancer Dephosphorylation Atlas

Ferreira¹,

Milani²,

Zambuzzi³

et al. 2011

Prostate Cancer - From Bench to Bedside

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The present textbook highlights many of the exciting discoveries made in the diagnosis and treatment of prostate cancer over the past decade. International thought leaders have contributed to this effort providing a comprehensive and state-of-the art review of the signaling pathways and genetic alterations essential in prostate cancer. This work provides an essential resource for healthcare professionals and scientists dedicated to this field. This textbook is dedicated to the efforts and advances made by our scientific community, realizing we have much to learn in striving to some day in the not too distant future cure this disease particularly among those with an aggressive tumor biology.

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Section: Protein Phosphatasesmentioning

confidence: 99%

Section: Mechanisms Of Ptp Catalysismentioning

confidence: 99%

Section: Mechanisms Of Ptp Catalysismentioning

confidence: 99%

Section: Acid Phosphatase 341 Signaling Featuresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Prostate Cancer Dephosphorylation Atlas

Ferreira¹,

Milani²,

Zambuzzi³

et al. 2011

Prostate Cancer - From Bench to Bedside

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Ecto-nucleotidases and Ecto-phosphatases from Leishmania and Trypanosoma Parasites

Freitas-Mesquita

Meyer‐Fernandes

2013

Subcellular Biochemistry

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Ecto-enzymes can be defined as membrane-bound proteins that have their active site facing the extracellular millieu. In trypanosomatids, the physiological roles of these enzymes remain to be completed elucidated; however, many important events have already been related to them, such as the survival of parasites during their complex life cycle and the successful establishment of host infection. This chapter focuses on two remarkable classes of ecto-enzymes: ecto-nucleotidases and ecto-phosphatases, summarizing their occurrence and possible physiological roles in Leishmania and Trypanosoma genera. Ecto-nucleotidases are characterized by their ability to hydrolyze extracellular nucleotides, playing an important role in purinergic signaling. By the action of these ecto-enzymes, parasites are capable of modulating the host immune system, which leads to a successful parasite infection. Furthermore, ecto-nucleotidases are also involved in the purine salvage pathway, acting in the generation of nucleosides that are able to cross plasma membrane via specialized transporters. Another important ecto-enzyme present in a vast number of pathogenic organisms is the ecto-phosphatase. These enzymes are able to hydrolyze extracellular phosphorylated substrates, releasing free inorganic phosphate that can be internalized by the cell, crossing the plasma membrane through a Pi-transporter. Ecto-phosphatases are also involved in the invasion and survival of parasite in the host cells. Several alternative functions have been suggested for these enzymes in parasites, such as participation in their proliferation, differentiation, nutrition and protection. In this context, the present chapter provides an overview of recent discoveries related to the occurrence of ecto-nucleotidase and ecto-phosphatase activities in Leishmania and Trypanosoma parasites.

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Identification and characterization of novel membrane-bound PRL protein tyrosine phosphatases from Setaria cervi, a bovine filarial parasite

2015

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A significant amount of protein tyrosine phosphatase (PTP) activity was detected in the detergent-soluble membrane-bound fraction of Setaria cervi, a bovine filarial parasite. The membrane-bound PTP activity was significantly inhibited when the adult parasites were exposed to compounds having antifilarial activity like aspirin and SK7 as well as phenylarsine oxide, a specific PTP inhibitor suggesting that this activity is stress regulated. Further, this enzyme was purified as a single protein of apparently 21 kDa using two different chromatographic techniques. The MALDI-MS/MS analysis of its peptides showed closest match with protein tyrosine phosphatase PRL (Aedes aegypti). This purified enzyme (named as PRL) showed maximum activity at pH 5.5/37 °C and hydrolysed para nitro phenyl phosphate (pNPP) at the highest rate followed by O-P-L-tyrosine and O-P-L-threonine. It showed significant inhibition by specific inhibitors of PTP such as sodium orthovanadate, phenylarsine oxide and ammonium molybdate and was activated by dithiothreitol (DTT). The active site modification studies suggested involvement of cysteine, arginine, histidine and aspartic acid in the catalytic activity of PRL. The activity of S. cervi PRL was also found to be resistant towards the external oxidative stress. Thus, S. cervi PRL could be taken as a potential target for the management of human lymphatic filariasis.

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Phosphatase activity characterization on the surface of intact bloodstream forms ofTrypanosoma brucei

Abstract: Abstract

Cited by 22 publications

References 32 publications

Prostate Cancer Dephosphorylation Atlas

Prostate Cancer Dephosphorylation Atlas

Ecto-nucleotidases and Ecto-phosphatases from Leishmania and Trypanosoma Parasites

Identification and characterization of novel membrane-bound PRL protein tyrosine phosphatases from Setaria cervi, a bovine filarial parasite

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