The PTPN2/PTPN1 inhibitor ABBV-CLS-484 unleashes potent anti-tumour immunity.

Immune checkpoint blockade is effective for some patients with cancer, but most are refractory to current immunotherapies and new approaches are needed to overcome resistance. The protein tyrosine phosphatases PTPN2 and PTPN1 are central regulators of inflammation, and their genetic deletion in either tumour cells or immune cells promotes anti-tumour immunity. However, phosphatases are challenging drug targets; in particular, the active site has been considered undruggable.

Identification and structure-based drug design of cell-active inhibitors of interleukin 17A at a novel C-terminal site.

Anti-IL17A therapies have proven effective for numerous inflammatory diseases including psoriasis, axial spondylitis and psoriatic arthritis. Modulating and/or antagonizing protein-protein interactions of IL17A cytokine binding to its cell surface receptors with oral therapies offers the promise to bring forward biologics-like efficacy in a pill to patients. We used an NMR-based fragment screen of recombinant IL17A to uncover starting points for small molecule IL17A antagonist discovery.

Small Molecule Phenotypic Screen Identifies Novel Regulators of LDLR Expression.

Alzheimer's Disease (AD) is a progressive neurodegenerative disease and the most common cause of dementia. The current treatment options for AD are limited to ameliorating cognitive decline temporarily and not reversing or preventing the progression of dementia. Hence, more effective therapeutic strategies are needed to combat this devastating disease.

DPM-1001 decreased copper levels and ameliorated deficits in a mouse model of Wilson's disease.

The levels of copper, which is an essential element in living organisms, are under tight homeostatic control. Inactivating mutations in ATP7B, a P-type Cu-ATPase that functions in copper excretion, promote aberrant accumulation of the metal, primarily the in liver and brain. This condition underlies Wilson's disease, a severe autosomal recessive disorder characterized by profound hepatic and neurological deficits.

Harnessing insulin- and leptin-induced oxidation of PTP1B for therapeutic development.

The protein tyrosine phosphatase PTP1B is a major regulator of glucose homeostasis and energy metabolism, and a validated target for therapeutic intervention in diabetes and obesity. Nevertheless, it is a challenging target for inhibitor development. Previously, we generated a recombinant antibody (scFv45) that recognizes selectively the oxidized, inactive conformation of PTP1B.

A potent, selective, and orally bioavailable inhibitor of the protein-tyrosine phosphatase PTP1B improves insulin and leptin signaling in animal models.

The protein-tyrosine phosphatase PTP1B is a negative regulator of insulin and leptin signaling and a highly validated therapeutic target for diabetes and obesity. Conventional approaches to drug development have produced potent and specific PTP1B inhibitors, but these inhibitors lack oral bioavailability, which limits their potential for drug development. Here, we report that DPM-1001, an analog of the specific PTP1B inhibitor trodusquemine (MSI-1436), is a potent, specific, and orally bioavailable inhibitor of PTP1B.

PTP1B inhibition suggests a therapeutic strategy for Rett syndrome.

The X-linked neurological disorder Rett syndrome (RTT) presents with autistic features and is caused primarily by mutations in a transcriptional regulator, methyl CpG-binding protein 2 (MECP2). Current treatment options for RTT are limited to alleviating some neurological symptoms; hence, more effective therapeutic strategies are needed. We identified the protein tyrosine phosphatase PTP1B as a therapeutic candidate for treatment of RTT.

Anxious moments for the protein tyrosine phosphatase PTP1B.

Chronic stress can lead to the development of anxiety and mood disorders. Thus, novel therapies for preventing adverse effects of stress are vitally important. Recently, the protein tyrosine phosphatase PTP1B was identified as a novel regulator of stress-induced anxiety.

A novel phosphatidic acid-protein-tyrosine phosphatase D2 axis is essential for ERBB2 signaling in mammary epithelial cells.

We used a loss-of-function screen to investigate the role of classical protein-tyrosine phosphatases (PTPs) in three-dimensional mammary epithelial cell morphogenesis and ERBB2 signaling. The study revealed a novel role for PTPD2 as a positive regulator of ERBB2 signaling. Suppression of PTPD2 attenuated the ERBB2-induced multiacinar phenotype in three-dimensional cultures specifically by inhibiting ERBB2-mediated loss of polarity and lumen filling.

Reactivation of oxidized PTP1B and PTEN by thioredoxin 1.

Unlabelled: The transient inactivation of protein phosphatases contributes to the efficiency and temporal control of kinase-dependent signal transduction. In particular, members of the protein tyrosine phosphatase family are known to undergo reversible oxidation of their active site cysteine. The thiol oxidation step requires activation of colocalized NADPH oxidases and is mediated by locally produced reactive oxygen species, in particular H2 O2 .

Targeting the disordered C terminus of PTP1B with an allosteric inhibitor.

PTP1B, a validated therapeutic target for diabetes and obesity, has a critical positive role in HER2 signaling in breast tumorigenesis. Efforts to develop therapeutic inhibitors of PTP1B have been frustrated by the chemical properties of the active site. We define a new mechanism of allosteric inhibition that targets the C-terminal, noncatalytic segment of PTP1B.

Evidence for hysteretic substrate channeling in the proline dehydrogenase and Δ1-pyrroline-5-carboxylate dehydrogenase coupled reaction of proline utilization A (PutA).

PutA (proline utilization A) is a large bifunctional flavoenzyme with proline dehydrogenase (PRODH) and Δ(1)-pyrroline-5-carboxylate dehydrogenase (P5CDH) domains that catalyze the oxidation of l-proline to l-glutamate in two successive reactions. In the PRODH active site, proline undergoes a two-electron oxidation to Δ(1)-pyrroline-5-carboxlylate, and the FAD cofactor is reduced. In the P5CDH active site, l-glutamate-γ-semialdehyde (the hydrolyzed form of Δ(1)-pyrroline-5-carboxylate) undergoes a two-electron oxidation in which a hydride is transferred to NAD(+)-producing NADH and glutamate.

The anti-inflammatory compound BAY-11-7082 is a potent inhibitor of protein tyrosine phosphatases.

The families of protein tyrosine phosphatases (PTPs) and protein tyrosine kinases (PTKs) function in a coordinated manner to regulate signal transduction events that are critical for cellular homeostasis. Aberrant tyrosine phosphorylation, resulting from disruption of either PTP or PTK function, has been shown to be the cause of major human diseases, including cancer and diabetes. Consequently, the characterization of small-molecule inhibitors of these kinases and phosphatases may not only provide molecular probes with which to define the significance of particular signaling events, but also may have therapeutic implications.

H2S-Induced sulfhydration of the phosphatase PTP1B and its role in the endoplasmic reticulum stress response.

Although originally considered toxic, hydrogen sulfide (H(2)S) has been implicated in mediating various biological processes. Nevertheless, its cellular targets and mode of action are not well understood. Protein tyrosine phosphatases (PTPs), which regulate numerous signal transduction pathways, use an essential cysteine residue at the active site, which is characterized by a low pK(a) and is susceptible to reversible oxidation.

Crystal structure of the bifunctional proline utilization A flavoenzyme from Bradyrhizobium japonicum.

The bifunctional proline catabolic flavoenzyme, proline utilization A (PutA), catalyzes the oxidation of proline to glutamate via the sequential activities of FAD-dependent proline dehydrogenase (PRODH) and NAD(+)-dependent Delta(1)-pyrroline-5-carboxylate dehydrogenase (P5CDH) domains. Although structures for some of the domains of PutA are known, a structure for the full-length protein has not previously been solved. Here we report the 2.

Dephosphorylation of the C-terminal tyrosyl residue of the DNA damage-related histone H2A.X is mediated by the protein phosphatase eyes absent.

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF. The phosphorylation status of Tyr-142 in H2A.

Characterization of a Helicobacter hepaticus putA mutant strain in host colonization and oxidative stress.

Helicobacter hepaticus is a gram-negative, spiral-shaped microaerophilic bacterium associated with chronic intestinal infection leading to hepatitis and colonic and hepatic carcinomas in susceptible strains of mice. In the closely related human pathogen Helicobacter pylori, L-proline is a preferred respiratory substrate and is found at significantly high levels in the gastric juice of infected patients. A previous study of the proline catabolic PutA flavoenzymes from H.

Proline modulates the intracellular redox environment and protects mammalian cells against oxidative stress.

The potential of proline to suppress reactive oxygen species (ROS) and apoptosis in mammalian cells was tested by manipulating intracellular proline levels exogenously and endogenously by overexpression of proline metabolic enzymes. Proline was observed to protect cells against H(2)O(2), tert-butyl hydroperoxide, and a carcinogenic oxidative stress inducer but was not effective against superoxide generators such as menadione. Oxidative stress protection by proline requires the secondary amine of the pyrrolidine ring and involves preservation of the glutathione redox environment.

Structure and kinetics of monofunctional proline dehydrogenase from Thermus thermophilus.

Proline dehydrogenase (PRODH) and Delta(1)-pyrroline-5-carboxylate dehydrogenase (P5CDH) catalyze the two-step oxidation of proline to glutamate. They are distinct monofunctional enzymes in all eukaryotes and some bacteria but are fused into bifunctional enzymes known as proline utilization A (PutA) in other bacteria. Here we report the first structure and biochemical data for a monofunctional PRODH.

Effect of farnesol on a mouse model of systemic candidiasis, determined by use of a DPP3 knockout mutant of Candida albicans.

This work extends our previous observation that the fungus Candida albicans secretes micromolar levels of farnesol and that accumulation of farnesol in vitro prevents the yeast-to-mycelium conversion in a quorum-sensing manner. What does farnesol do in vivo? The purpose of this study was to determine the role of farnesol during infection with a well-established mouse model of systemic candidiasis with C. albicans A72 administered by tail vein injection.

Oxygen reactivity of PutA from Helicobacter species and proline-linked oxidative stress.

Proline is converted to glutamate in two successive steps by the proline utilization A (PutA) flavoenzyme in gram-negative bacteria. PutA contains a proline dehydrogenase domain that catalyzes the flavin adenine dinucleotide (FAD)-dependent oxidation of proline to delta1-pyrroline-5-carboxylate (P5C) and a P5C dehydrogenase domain that catalyzes the NAD+-dependent oxidation of P5C to glutamate. Here, we characterize PutA from Helicobacter hepaticus (PutA(Hh)) and Helicobacter pylori (PutA(Hp)) to provide new insights into proline metabolism in these gastrointestinal pathogens.

Kinetic and thermodynamic analysis of Bradyrhizobium japonicum PutA-membrane associations.

In Escherichia coli, proline induces tight membrane binding of the PutA flavoenzyme and transforms PutA from a transcriptional repressor to a membrane-associated proline catabolic enzyme. In other gram-negative bacteria such as Bradyrhizobium japonicum, PutA lacks DNA binding activity and functions only as a proline catabolic enzyme. Here, we characterize the membrane binding properties of PutA from B.

Characterization of a bifunctional PutA homologue from Bradyrhizobium japonicum and identification of an active site residue that modulates proline reduction of the flavin adenine dinucleotide cofactor.

PutA is a bifunctional flavoenzyme in bacteria that catalyzes the four-electron oxidation of proline to glutamate. In certain prokaryotes such as Escherichia coli, PutA is also a transcriptional repressor of the proline utilization (put) genes and thus is trifunctional. In this work, we have begun to assess differences between bifunctional and trifunctional PutA enzymes by examining the PutA protein from Bradyrhizobium japonicum (BjPutA).