Cellular immune reactions against non-self-epitopes require activation of cytotoxic CD8+ T-cells via cross-presentation of MHC class I-restricted peptides by professional antigen presenting cells (pAPCs), with the consequent detection and elimination of cells expressing the same antigens via the endogenous (direct) pathway. The source of peptides for the endogenous pathway is constituted of alternative mRNA translation products; however, it is still unclear which source of peptides is used for cross-presentation. Furthermore, the presentation of non-canonical translation products, produced during a non-conventional translation event, on class I molecules of tumor cells has been reported but how these peptides are generated, presented to pAPCs, and their capacity to stimulate CD8+ T cells is still not known. Here, we report that pioneer translation peptides (PTPs) derived from intron or exon pre-mRNAs can serve as tumor-associated antigens (TA-PTPs) and are delivered from the producing tumor cells to pAPCs via exosomes where they are processed by the cytosolic pathway. Injection of TA-PTPs and tumor-derived exosomes efficiently induce CD8+ T-cell proliferation and prevent tumor growth in mice. Our results show that TA-PTPs represent an efficient source of antigenic peptides for CD8+ T cell activation and that full-length proteins are not required for cross-presentation. These findings can have interesting implications for generating tolerance and for designing vectors to generate vaccines.

• Klíčová slova
• Exosomes, MHC-I antigen cross presentation, pioneer translation products, tumor rejection, vaccines,
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Ischemia/reperfusion (I/R) injury is mediated in large part by opening of the mitochondrial permeability transition pore (PTP). Consequently, inhibitors of the PTP hold great promise for the treatment of a variety of cardiovascular disorders. At present, PTP inhibition is obtained only through the use of drugs (e.g. cyclosporine A, CsA) targeting cyclophilin D (CyPD) which is a key modulator, but not a structural component of the PTP. This limitation might explain controversial findings in clinical studies. Therefore, we investigated the protective effects against I/R injury of small-molecule inhibitors of the PTP (63 and TR002) that do not target CyPD. Both compounds exhibited a dose-dependent inhibition of PTP opening in isolated mitochondria and were more potent than CsA. Notably, PTP inhibition was observed also in mitochondria devoid of CyPD. Compounds 63 and TR002 prevented PTP opening and mitochondrial depolarization induced by Ca2+ overload and by reactive oxygen species in neonatal rat ventricular myocytes (NRVMs). Remarkably, both compounds prevented cell death, contractile dysfunction and sarcomeric derangement induced by anoxia/reoxygenation injury in NRVMs at sub-micromolar concentrations, and were more potent than CsA. Cardioprotection was observed also in adult mouse ventricular myocytes and human iPSc-derived cardiomyocytes, as well as ex vivo in perfused hearts. Thus, this study demonstrates that 63 and TR002 represent novel cardioprotective agents that inhibit PTP opening independent of CyPD targeting.

• Klíčová slova
• Caffeine (PubChem CID: 2519), Calcimycin (PubChem CID: 40486), Cardiomyocytes, Cardioprotection, Compound 63 (PubChem CID: 75204518), Cyclosporine A (PubChem CID: 5284373), Ischemia, MitoParaquat (PubChem CID: 129909777), Mitochondria, Permeability transition, Reperfusion,
• MeSH
• buněčné linie MeSH
• kardiomyocyty účinky léků   MeSH
• kardiotonika farmakologie   terapeutické užití   MeSH
• knihovny malých molekul farmakologie   terapeutické užití   MeSH
• kultivované buňky MeSH
• lidé MeSH
• myši inbrední C57BL MeSH
• potkani Sprague-Dawley MeSH
• potkani Wistar MeSH
• přechodový pór mitochondriální permeability antagonisté a inhibitory   metabolismus   MeSH
• reperfuzní poškození myokardu farmakoterapie   metabolismus   patologie   MeSH
• srdeční mitochondrie účinky léků   metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• kardiotonika MeSH
• knihovny malých molekul MeSH
• přechodový pór mitochondriální permeability MeSH

Receptor tyrosine kinases (RTKs) are membrane receptors that regulate many fundamental cellular processes. A tight regulation of RTK signaling is fundamental for development and survival, and an altered signaling by RTKs can cause cancer. RTKs are localized at the plasma membrane (PM) and the major regulatory mechanism of signaling of RTKs is their endocytosis and degradation. In fact, RTKs at the cell surface bind ligands with their extracellular domain, become active, and are rapidly internalized where the temporal extent of signaling, attenuation, and downregulation are modulated. However, other mechanisms of signal attenuation and termination are known. Indeed, inhibition of RTKs' activity may occur through the modulation of the phosphorylation state of RTKs and the interaction with specific proteins, whereas antagonist ligands can inhibit the biological responses mediated by the receptor. Another mechanism concerns the expression of endogenous inactive receptor variants that are deficient in RTK activity and take part to inactive heterodimers or hetero-oligomers. The downregulation of RTK signals is fundamental for several cellular functions and the homeostasis of the cell. Here, we will review the mechanisms of signal attenuation and termination of RTKs, focusing on FGFRs.

• Klíčová slova
• FGFRs, PTPs, RTKs, degradation, kinases, termination of signaling, ubiquitination,
• MeSH
• down regulace MeSH
• lidé MeSH
• lyzozomy metabolismus   MeSH
• mutace genetika   MeSH
• signální transdukce * MeSH
• tyrosinkinasové receptory antagonisté a inhibitory   genetika   metabolismus   MeSH
• ubikvitinace MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• tyrosinkinasové receptory MeSH

A 67 kDa cytosolic FERM domain containing protein having significant protein tyrosine phosphatases activity (PTPL) has been purified to homogeneity from Setaria cervi, a bovine filarial parasite. The MALDI-MS/MS analysis of the purified protein revealed 16 peptide peaks showing nearest match to Brugia malayi Moesin/ezrin/radixin homolog 1 protein and one peptide showing significant similarity with a region lying in the catalytic domain of human PTPD1. PTPL showed significant cross reactivity with the human PTP1B antibody and colocalize with actin in the coelomyrian cells of hypodermis in the parasite. PTPL was stress regulated as it showed marked decrease in the expression when exposed to Aspirin, an antifilarial drug and Phenylarsine Oxide, PTP inhibitor.

• Klíčová slova
• Cytoskeletal protein, FERM domain, Filariasis, Immunostaining, MALDI MS/MS, Tyrosine phosphatase,
• MeSH
• arsenikové přípravky farmakologie   MeSH
• Aspirin farmakologie   MeSH
• cytosol metabolismus   MeSH
• katalytická doména MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• proteiny červů chemie   izolace a purifikace   metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• Setaria (Nematoda) chemie   účinky léků   patogenita   MeSH
• terciární struktura proteinů MeSH
• tyrosinfosfatasy chemie   metabolismus   MeSH
• zkřížené reakce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• arsenikové přípravky MeSH
• Aspirin MeSH
• oxophenylarsine MeSH Prohlížeč
• proteiny červů MeSH
• tyrosinfosfatasy MeSH

INTRODUCTION: Autoinflammatory diseases are characterized by dysregulation of innate immune system leading to spontaneous sterile inflammation. One of the well-established animal models of this group of disorders is the mouse strain Pstpip2cmo . In this strain, the loss of adaptor protein PSTPIP2 leads to the autoinflammatory disease chronic multifocal osteomyelitis. It is manifested by sterile inflammation of the bones and surrounding soft tissues of the hind limbs and tail. The disease development is propelled by elevated production of IL-1β and reactive oxygen species by neutrophil granulocytes. However, the molecular mechanisms linking PSTPIP2 and these pathways have not been established. Candidate proteins potentially involved in these mechanisms include PSTPIP2 binding partners, PEST family phosphatases (PEST-PTPs) and phosphoinositide phosphatase SHIP1. METHODS: To address the role of these proteins in PSTPIP2-mediated control of inflammation, we have generated mouse strains in which PEST-PTP or SHIP1 binding sites in PSTPIP2 have been disrupted. In these mouse strains, we followed disease symptoms and various inflammation markers. RESULTS: Our data show that mutation of the PEST-PTP binding site causes symptomatic disease, whereas mice lacking the SHIP1 interaction site remain asymptomatic. Importantly, both binding partners of PSTPIP2 contribute equally to the control of IL-1β production, while PEST-PTPs have a dominant role in the regulation of reactive oxygen species. In addition, the interaction of PEST-PTPs with PSTPIP2 regulates the production of the chemokine CXCL2 by neutrophils. Its secretion likely creates a positive feedback loop that drives neutrophil recruitment to the affected tissues. CONCLUSIONS: We demonstrate that PSTPIP2-bound PEST-PTPs and SHIP1 together control the IL-1β pathway. In addition, PEST-PTPs have unique roles in the control of reactive oxygen species and chemokine production, which in the absence of PEST-PTP binding to PSTPIP2 shift the balance towards symptomatic disease.

• Klíčová slova
• PEST-family phosphatases, PSTPIP2, SHIP1, autoinflammation, chronic multifocal osteomyelitis, neutrophils,
• MeSH
• adaptorové proteiny signální transdukční * metabolismus   MeSH
• cytoskeletální proteiny * metabolismus   MeSH
• myši MeSH
• neutrofily * MeSH
• osteomyelitida MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• zánět MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adaptorové proteiny signální transdukční * MeSH
• cytoskeletální proteiny * MeSH
• Pstpip2 protein, mouse MeSH Prohlížeč
• reaktivní formy kyslíku MeSH

Protein tyrosine phosphatases (PTPs) are increasingly recognized as important effectors of host-pathogen interactions. Since Guan and Dixon reported in 1990 that phosphatase YopH serves as an essential virulence determinant of Yersinia, the field shifted significantly forward, and dozens of PTPs were identified in various microorganisms and even in viruses. The discovery of extensive tyrosine signaling networks in non-metazoan organisms refuted the moth-eaten paradigm claiming that these organisms rely exclusively on phosphoserine/phosphothreonine signaling. Similarly to humans, phosphotyrosine signaling is thought to comprise a small fraction of total protein phosphorylation, but plays a disproportionately important role in cell-cycle control, differentiation, and invasiveness. Here we summarize the state-of-art knowledge on PTPs of important non-metazoan pathogens (Listeria monocytogenes, Staphylococcus aureus, Porphyromonas gingivalis, Caulobacter crescentus, Yersinia, Synechocystis, Leishmania, Plasmodium falciparum, Entamoeba histolytica, etc.), and focus also at the microbial proteins affecting directly or indirectly the PTPs of the host (Mycobacterium tuberculosis MTSA-10, Bacillus anthracis anthrax toxin, streptococcal β protein, Helicobacter pylori CagA and VacA, Leishmania GP63 and EF-1α, Plasmodium hemozoin, etc.). This is the first review summarizing the knowledge on biological activity and pharmacological inhibition of non-metazoan PTPs, with the emphasis of those important in host-pathogen interactions. Targeting of numerous non-metazoan PTPs is simplified by the fact that they act either as ectophosphatases or are secreted outside of the pathogen. Interfering with tyrosine phosphorylation represents a powerful pharmacologic approach, and even though the PTP inhibitors are difficult to develop, lifting the fog of phosphatase inhibition is of the great market potential and further clinical impact.

• MeSH
• Bacteria účinky léků   enzymologie   MeSH
• bakteriální proteiny antagonisté a inhibitory   metabolismus   MeSH
• inhibitory enzymů chemie   farmakologie   MeSH
• interakce hostitele a patogenu MeSH
• Leishmania účinky léků   enzymologie   MeSH
• lidé MeSH
• protozoální proteiny antagonisté a inhibitory   metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• tyrosinfosfatasy antagonisté a inhibitory   metabolismus   MeSH
• virové proteiny antagonisté a inhibitory   metabolismus   MeSH
• viry účinky léků   enzymologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• bakteriální proteiny MeSH
• inhibitory enzymů MeSH
• protozoální proteiny MeSH
• reaktivní formy kyslíku MeSH
• tyrosinfosfatasy MeSH
• virové proteiny MeSH

The earliest known biochemical step that occurs after ligand binding to the multichain immune recognition receptor is tyrosine phosphorylation of the receptor subunits. In mast cells and basophils activated by multivalent antigen-IgE complexes, this step is mediated by Src family kinase Lyn, which phosphorylates the high affinity IgE receptor (Fc epsilonRI). However, the exact molecular mechanism of this phosphorylation step is incompletely understood. In this study, we tested the hypothesis that changes in activity and/or topography of protein-tyrosine phosphatases (PTPs) could play a major role in the Fc epsilonRI triggering. We found that exposure of rat basophilic leukemia cells or mouse bone marrow-derived mast cells to PTP inhibitors, H(2)O(2) or pervanadate, induced phosphorylation of the Fc epsilonRI subunits, similarly as Fc epsilonRI triggering. Interestingly, and in sharp contrast to antigen-induced activation, neither H(2)O(2) nor pervanadate induced any changes in the association of Fc epsilonRI with detergent-resistant membranes and in the topography of Fc epsilonRI detectable by electron microscopy on isolated plasma membrane sheets. In cells stimulated with pervanadate, H(2)O(2) or antigen, enhanced oxidation of active site cysteine of several PTPs was detected. Unexpectedly, most of oxidized phosphatases bound to the plasma membrane were associated with the actin cytoskeleton. Several PTPs (SHP-1, SHP-2, hematopoietic PTP, and PTP-MEG2) showed changes in their enzymatic activity and/or oxidation state during activation. Based on these and other data, we propose that down-regulation of enzymatic activity of PTPs and/or changes in their accessibility to the substrates play a key role in initial tyrosine phosphorylation of the Fc epsilonRI and other multichain immune receptors.

• MeSH
• aktivace enzymů účinky léků   genetika   imunologie   MeSH
• antigeny imunologie   metabolismus   farmakologie   MeSH
• fosforylace účinky léků   genetika   imunologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• krysa rodu Rattus MeSH
• mastocyty imunologie   metabolismus   MeSH
• membránové mikrodomény genetika   imunologie   metabolismus   MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• oxidace-redukce účinky léků   MeSH
• oxidancia farmakologie   MeSH
• peroxid vodíku farmakologie   MeSH
• receptory IgE genetika   imunologie   metabolismus   MeSH
• skupina kinas odvozených od src-genu genetika   imunologie   metabolismus   MeSH
• transport proteinů účinky léků   genetika   imunologie   MeSH
• tyrosinfosfatasy antagonisté a inhibitory   genetika   imunologie   metabolismus   MeSH
• vanadáty farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny MeSH
• inhibitory enzymů MeSH
• lyn protein-tyrosine kinase MeSH Prohlížeč
• oxidancia MeSH
• peroxid vodíku MeSH
• pervanadate MeSH Prohlížeč
• receptory IgE MeSH
• skupina kinas odvozených od src-genu MeSH
• tyrosinfosfatasy MeSH
• vanadáty MeSH

Protein tyrosine phosphatases (PTPs) are considered to be involved in the etiology of diabetes mellitus, neural diseases such as Alzheimer;s and Parkinson;s disease, regulation of allergy and inflammation, or they are even considered to be responsible for the pathogens; virulence in vivo. Since discovery of first PTP inhibitors such as dephostatin in early 90th years, the research moved on toward search for inhibitors specific for the individual PTP molecules. Currently, dozens of new PTP inhibitors are reported each year, ranging from natural products, natural product analogs, peptides, phosphonates, nonpeptidic inhibitors, mimotopes, metal-containing inhibitors, redox inhibitors, to simply silencing RNAs as widely used inhibitors of PTP expression. Several currently used drugs also show PTP inhibitory activity. Among them are sodium stibogluconate, phenylarsine oxide, alendronate, etidronate, vanadate, gallium nitrate, suramin, or aplidin. However, the market is still waiting for the first clinically approved selective PTP inhibitor. Here in this review are described inhibitors of activity or expression of the particular classical PTPs, with emphasis on specific inhibition of the respective PTP over the others. The inhibitors are not classified according to their chemical composition, but according to their biological activity, which should help to simplify search for inhibitors of particular classical PTPs. Even though PTP inhibitors are difficult to develop, lifting the fog of phosphatase inhibition is of the great market potential and further clinical impact.

• MeSH
• inhibitory enzymů chemie   farmakologie   MeSH
• lidé MeSH
• tyrosinfosfatasy antagonisté a inhibitory   chemie   genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• inhibitory enzymů MeSH
• tyrosinfosfatasy MeSH

SIGNIFICANCE: Redox modifications of thiols serve as a molecular code enabling precise and complex regulation of protein tyrosine phosphatases (PTPs) and other proteins. Particular gasotransmitters and even the redox modifications themselves affect each other, of which a typical example is S-nitrosylation-mediated protection against the further oxidation of protein thiols. RECENT ADVANCES: For a long time, PTPs were considered constitutively active housekeeping enzymes. This view has changed substantially over the last two decades, and the PTP family is now recognized as a group of tightly and flexibly regulated fundamental enzymes. In addition to the conventional ways in which they are regulated, including noncovalent interactions, phosphorylation, and oxidation, the evidence that has accumulated during the past two decades suggests that many of these enzymes are also modulated by gasotransmitters, namely by nitric oxide (NO) and hydrogen sulfide (H2S). CRITICAL ISSUES: The specificity and selectivity of the methods used to detect nitrosylation and sulfhydration remains to be corroborated, because several researchers raised the issue of false-positive results, particularly when using the most widespread biotin switch method. Further development of robust and straightforward proteomic methods is needed to further improve our knowledge of the full extent of the gasotransmitters-mediated changes in PTP activity, selectivity, and specificity. FURTHER DIRECTIONS: Results of the hitherto performed studies on gasotransmitter-mediated PTP signaling await translation into clinical medicine and pharmacotherapeutics. In addition to directly affecting the activity of particular PTPs, the use of reversible S-nitrosylation as a protective mechanism against oxidative stress should be of high interest.

• MeSH
• aktivace enzymů MeSH
• lidé MeSH
• reaktivní formy dusíku metabolismus   MeSH
• sulfan metabolismus   MeSH
• tyrosinfosfatasy metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• reaktivní formy dusíku MeSH
• sulfan MeSH
• tyrosinfosfatasy MeSH

Peptides presented on major histocompatibility (MHC) class I molecules form an essential part of the immune system's capacity to detect virus-infected or transformed cells. Earlier works have shown that pioneer translation peptides (PTPs) for the MHC class I pathway are as efficiently produced from introns as from exons, or from mRNAs targeted for the nonsense-mediated decay pathway. The production of PTPs is a target for viral immune evasion but the underlying molecular mechanisms that govern this non-canonical translation are unknown. Here, we have used different approaches to show how events taking place on the nascent transcript control the synthesis of PTPs and full-length proteins. By controlling the subcellular interaction between the G-quadruplex structure (G4) of a gly-ala encoding mRNA and nucleolin (NCL) and by interfering with mRNA maturation using multiple approaches, we demonstrate that antigenic peptides derive from a nuclear non-canonical translation event that is independently regulated from the synthesis of full-length proteins. Moreover, we show that G4 are exploited to control mRNA localization and translation by distinguishable mechanisms that are targets for viral immune evasion.

• MeSH
• antigeny genetika   imunologie   MeSH
• buněčné jádro genetika   imunologie   MeSH
• G-kvadruplexy MeSH
• histokompatibilita - antigeny třídy I genetika   imunologie   MeSH
• imunitní únik genetika   imunologie   MeSH
• lidé MeSH
• messenger RNA genetika   imunologie   MeSH
• nonsense mediated mRNA decay genetika   imunologie   MeSH
• peptidy genetika   imunologie   MeSH
• proteosyntéza genetika   imunologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny MeSH
• histokompatibilita - antigeny třídy I MeSH
• messenger RNA MeSH
• peptidy MeSH