Haploinsufficiency in PTPN2 leads to early-onset systemic autoimmunity from Evans syndrome to lupus.

An exome sequencing strategy employed to identify pathogenic variants in patients with pediatric-onset systemic lupus or Evans syndrome resulted in the discovery of six novel monoallelic mutations in PTPN2. PTPN2 is a phosphatase that acts as an essential negative regulator of the JAK/STAT pathways. All mutations led to a loss of PTPN2 regulatory function as evidenced by in vitro assays and by hyperproliferation of patients' T cells.

EGCG-like non-competitive inhibitor of DYRK1A rescues cognitive defect in a down syndrome model.

Overexpression of the chromosome 21 DYRK1A gene induces morphological defects and cognitive impairments in individuals with Down syndrome (DS) and in DS mice models. Aging neurons of specific brain regions of patients with Alzheimer's disease, DS and Pick's disease have increased DYRK1A immunoreactivity suggesting a possible association of DYRK1A with neurofibrillary tangle pathology. Epigallocatechin-3-gallate (EGCG) displays appreciable inhibition of DYRK1A activity and, contrary to all other published inhibitors, EGCG is a non-competitive inhibitor of DYRK1A.

Structural and enzymatic evidence for the methylation of the ACK1 tyrosine kinase by the histone lysine methyltransferase SETD2.

SETD2 (SET-domain containing protein 2) is a histone methyltransferase (HMT) of the SET family responsible for the trimethylation of K36 of histone H3, thus producing the epigenetic mark H3K36me3. Recent studies have shown that certain SET family HMTs, such as SMYD2, SMYD3 or SETDB1 can also methylate protein kinases and therefore be involved in signaling pathways. Here we provide structural and enzymatic evidence showing that SETD2 methylates the protein tyrosine kinase ACK1 in vitro.

Hypothalamic astrocytes control systemic glucose metabolism and energy balance.

The hypothalamus is key in the control of energy balance. However, strategies targeting hypothalamic neurons have failed to provide viable options to treat most metabolic diseases. Conversely, the role of astrocytes in systemic metabolic control has remained largely unexplored.

Biochemical, Enzymatic, and Computational Characterization of Recurrent Somatic Mutations of the Human Protein Tyrosine Phosphatase PTP1B in Primary Mediastinal B Cell Lymphoma.

Human protein tyrosine phosphatase 1B (PTP1B) is a ubiquitous non-receptor tyrosine phosphatase that serves as a major negative regulator of tyrosine phosphorylation cascades of metabolic and oncogenic importance such as the insulin, epidermal growth factor receptor (EGFR), and JAK/STAT pathways. Increasing evidence point to a key role of PTP1B-dependent signaling in cancer. Interestingly, genetic defects in PTP1B have been found in different human malignancies.

Identification of Modulators of the Aryl Hydrocarbon Receptor and Characterization of Transcriptomic and Metabolic AhR-1 Profiles.

The Aryl hydrocarbon Receptor (AhR) is a xenobiotic sensor in vertebrates, regulating the metabolism of its own ligands. However, no ligand has been identified to date for any AhR in invertebrates. In  , the AhR ortholog, AHR-1, displays physiological functions.

The Benzene Hematotoxic and Reactive Metabolite 1,4-Benzoquinone Impairs the Activity of the Histone Methyltransferase SET Domain Containing 2 (SETD2) and Causes Aberrant Histone H3 Lysine 36 Trimethylation (H3K36me3).

Human SETD2 is the unique histone methyltransferase that generates H3K36 trimethylation (H3K36me3), an epigenetic mark that plays a key role in normal hematopoiesis. Interestingly, recurrent inactivating mutations of SETD2 and aberrant H3K36me3 are increasingly reported to be involved in hematopoietic malignancies. Benzene (BZ) is a ubiquitous environmental pollutant and carcinogen that causes leukemia.

Human CREBBP acetyltransferase is impaired by etoposide quinone, an oxidative and leukemogenic metabolite of the anticancer drug etoposide through modification of redox-sensitive zinc-finger cysteine residues.

Etoposide is an extensively prescribed anticancer drug that, unfortunately, causes therapy-related leukemia. The mechanisms by which etoposide induces secondary hematopoietic malignancies are poorly documented. However, etoposide-related leukemogenesis is known to depend on oxidative metabolites of etoposide, notably etoposide quinone, that can react with protein cysteine residues such as in topoisomerases II.

Lung Antioxidant Depletion: A Predictive Indicator of Cellular Stress Induced by Ambient Fine Particles.

Regulations on ambient particulate matter (PM) are becoming more stringent because of adverse health effects arising from PM exposure. PM-induced oxidant production is a key mechanism behind the observed health effects and is heavily dependent on PM composition. Measurement of the intrinsic oxidative potential (OP) of PM could provide an integrated indicator of PM bioreactivity and could serve as a better metric of PM hazard exposure than PM mass concentration.

Benzoquinone, a leukemogenic metabolite of benzene, catalytically inhibits the protein tyrosine phosphatase PTPN2 and alters STAT1 signaling.

Protein tyrosine phosphatase, nonreceptor type 2 (PTPN2) is mainly expressed in hematopoietic cells, where it negatively regulates growth factor and cytokine signaling. PTPN2 is an important regulator of hematopoiesis and immune/inflammatory responses, as evidenced by loss-of-function mutations of in leukemia and lymphoma and knockout mice studies. Benzene is an environmental chemical that causes hematological malignancies, and its hematotoxicity arises from its bioactivation in the bone marrow to electrophilic metabolites, notably 1,4-benzoquinone, a major hematotoxic benzene metabolite.

T-Cell Protein Tyrosine Phosphatase Is Irreversibly Inhibited by Etoposide-Quinone, a Reactive Metabolite of the Chemotherapy Drug Etoposide.

Etoposide is a widely prescribed anticancer drug that is, however, associated with an increased risk of secondary leukemia. Although the molecular basis underlying the development of these leukemias remains poorly understood, increasing evidence implicates the interaction of etoposide metabolites [i.e.

A readout of metabolic efficiency in arylamine N-acetyltransferase-deficient mice reveals minor energy metabolism changes.

Recent studies have revealed a possible link between the activities of polymorphic arylamine N-acetyltransferases (NATs) and energy metabolism. We used a Nat1/Nat2 double knockout (KO) mouse model to demonstrate that ablation of the two Nat genes is associated with modest, intermittent alterations in respiratory exchange rate. Pyruvate tolerance tests show that double KO mice have attenuated hepatic gluconeogenesis when maintained on a high-fat/high-sucrose diet.

DYRK1A inhibition and cognitive rescue in a Down syndrome mouse model are induced by new fluoro-DANDY derivatives.

Inhibition of DYRK1A kinase, produced by chromosome 21 and consequently overproduced in trisomy 21 subjects, has been suggested as a therapeutic approach to treating the cognitive deficiencies observed in Down syndrome (DS). We now report the synthesis and potent DYRK1A inhibitory activities of fluoro derivatives of 3,5-di(polyhydroxyaryl)-7-azaindoles (F-DANDYs). One of these compounds (3-(4-fluorophenyl)-5-(3,4-dihydroxyphenyl)-1H-pyrrolo[2,3-b]pyridine, 5a) was selected for in vivo studies of cognitive rescuing effects in a standard mouse model of DS (Ts65Dn line).

Human Arylamine -Acetyltransferase 1 Is Inhibited by the Dithiocarbamate Pesticide Thiram.

Thiram (tetramethylthiuram disulfide) is a representative dithiocarbamate (DTC) pesticide used in both the field and as a seed protectant. The widespread use of Thiram and other DTC pesticides has raised concerns for health, because these compounds can exert neuropathic, endocrine disruptive, and carcinogenic effects. These toxic effects are thought to rely, at least in part, on the reaction of Thiram (and certain of its metabolites) with cellular protein thiols with subsequent loss of protein function.

Oxidative potential of particulate matter 2.5 as predictive indicator of cellular stress.

Particulate air pollution being recognized to be responsible for short and long term health effects, regulations for particulate matter with an aerodynamic diameter less than 2.5 (PM) are more and more restrictive. PM regulation is based on mass without taking into account PM composition that drives toxicity.

Overexpression of the DYRK1A Gene (Dual-Specificity Tyrosine Phosphorylation-Regulated Kinase 1A) Induces Alterations of the Serotoninergic and Dopaminergic Processing in Murine Brain Tissues.

Trisomy 21 (T21) or Down syndrome (DS) is the most common genetic disorder associated with intellectual disability and affects around 5 million persons worldwide. Neuroanatomical phenotypes associated with T21 include slight reduction of brain size and weight, abnormalities in several brain areas including spines dysgenesis, dendritic morphogenesis, and early neuroanatomical characteristics of Alzheimer's disease. Monoamine neurotransmitters are involved in dendrites development, functioning of synapses, memory consolidation, and their levels measured in the cerebrospinal fluid, blood, or brain areas that are modified in individuals with T21.

Molecular Mechanisms of Allosteric Inhibition of Brain Glycogen Phosphorylase by Neurotoxic Dithiocarbamate Chemicals.

Dithiocarbamates (DTCs) are important industrial chemicals used extensively as pesticides and in a variety of therapeutic applications. However, they have also been associated with neurotoxic effects and in particular with the development of Parkinson-like neuropathy. Although different pathways and enzymes (such as ubiquitin ligases or the proteasome) have been identified as potential targets of DTCs in the brain, the molecular mechanisms underlying their neurotoxicity remain poorly understood.

An Isozyme-specific Redox Switch in Human Brain Glycogen Phosphorylase Modulates Its Allosteric Activation by AMP.

Brain glycogen and its metabolism are increasingly recognized as major players in brain functions. Moreover, alteration of glycogen metabolism in the brain contributes to neurodegenerative processes. In the brain, both muscle and brain glycogen phosphorylase isozymes regulate glycogen mobilization.

Identification of cancer chemopreventive isothiocyanates as direct inhibitors of the arylamine N-acetyltransferase-dependent acetylation and bioactivation of aromatic amine carcinogens.

Aromatic amines (AAs) are chemicals of industrial, pharmacological and environmental relevance. Certain AAs, such as 4-aminobiphenyl (4-ABP), are human carcinogens that require enzymatic metabolic activation to reactive chemicals to form genotoxic DNA adducts. Arylamine N-acetyltransferases (NAT) are xenobiotic metabolizing enzymes (XME) that play a major role in this carcinogenic bioactivation process.

Regulation of Aquaporin 3 Expression by the AhR Pathway Is Critical to Cell Migration.

The regulation of cell migration is a key factor for the dissemination of metastatic cells during tumor progression. Aquaporins are membrane channels which allow transmembrane fluxes of water and glycerol in cells in a variety of mammalian tissues. Here, we show that AQP3, which has been incriminated in cancer progression, is regulated by the AhR, or dioxin receptor.

An acetyltransferase assay for CREB-binding protein based on reverse phase-ultra-fast liquid chromatography of fluorescent histone H3 peptides.

CREB-binding protein (CBP) is a lysine acetyltransferase that regulates transcription by acetylating histone and non-histone substrates. Defects in CBP activity are associated with hematologic malignancies, neurodisorders, and congenital malformations. Sensitive and quantitative enzymatic assays are essential to better characterize the pathophysiological features of CBP.

Screen for soil fungi highly resistant to dichloroaniline uncovers mostly Fusarium species.

Arylamines are frequent pollutants in soils. Fungi have proven to be efficient in detoxifying these chemicals by acetylating them using arylamine N-acetyl transferase enzymes. Here, we selected from natural soils fungi highly resistant to 3,4-dichloroaniline (DCA).

A RP-UFLC Assay for Protein Tyrosine Phosphatases: Focus on Protein Tyrosine Phosphatase Non-Receptor Type 2 (PTPN2).

Protein tyrosine phosphatases (PTPs) are involved in numerous signaling pathways and dysfunctions of certain of these enzymes have been linked to several human diseases including cancer and autoimmune diseases. PTPN2 is a PTP mainly expressed in hematopoietic cells and involved in growth factor and JAK/STAT signaling pathways. Loss of function analyses in patients with mutation/deletion of the PTPN2 gene and knock-out mouse models indicate that PTPN2 acts as a tumor suppressor in T-cell malignancies and as a regulator of inflammation and immunity.

Parkinsonism-associated protein DJ-1/Park7 is a major protein deglycase that repairs methylglyoxal- and glyoxal-glycated cysteine, arginine, and lysine residues.

Glycation is an inevitable nonenzymatic covalent reaction between proteins and endogenous reducing sugars or dicarbonyls (methylglyoxal, glyoxal) that results in protein inactivation. DJ-1 was reported to be a multifunctional oxidative stress response protein with poorly defined function. Here, we show that human DJ-1 is a protein deglycase that repairs methylglyoxal- and glyoxal-glycated amino acids and proteins by acting on early glycation intermediates and releases repaired proteins and lactate or glycolate, respectively.