Search results for "PHOSPHATASE"

Specific Defects in Different Transcription Complexes Compensate for the Requirement of the Negative Cofactor 2 Repressor in Saccharomyces cerevisiae

2007

Abstract Negative cofactor 2 (NC2) has been described as an essential and evolutionarily conserved transcriptional repressor, although in vitro and in vivo experiments suggest that it can function as both a positive and a negative effector of transcription. NC2 operates by interacting with the core promoter and components of the basal transcription machinery, like the TATA-binding protein (TBP). In this work, we have isolated mutants that suppress the growth defect caused by the depletion of NC2. We have identified mutations affecting components of three different complexes involved in the control of basal transcription: the mediator, TFIIH, and RNA pol II itself. Mutations in RNA pol II in…

Hyperphosphorylation of Msn2p and Msn4p in response to heat shock and the diauxic shift is inhibited by cAMP in Saccharomyces cerevisiae.

2000

In response to various stresses, as well as during the diauxic transition, the Msn2p and Msn4p transcription factors of Saccharomyces cerevisiae are activated and induce a large set of genes. This activation is inhibited by the Ras/cAMP/PKA (cAMP-dependent protein kinase) pathway. Here we show by immunoblotting experiments that Msn2p and Msn4p are phosphorylated in vivo during growth on glucose, and become hyperphosphorylated at the diauxic transition and upon heat shock. This hyperphosphorylation is correlated with activation of Msn2/4p-dependent transcription. An increased level of cAMP prevents and reverses these hyperphosphorylations, indicating that kinases other than PKA are involved.…

In vitro and in vivo efficacy of PEGylated diisopropyl fluorophosphatase (DFPase)

2011

Highly toxic organophosphorus compounds that irreversibly inhibit the enzyme acetycholinesterase (AChE), including nerve agents like tabun, sarin, or soman, still pose a credible threat to civilian populations and military personnel. New therapeutics that can be used as a pretreatment or after poisoning with these compounds, complementing existing treatment schemes such as the use of atropine and AChE reactivating oximes, are currently the subject of intense research. A prominent role among potential candidates is taken by enzymes that can detoxify nerve agents by hydrolysis. Diisopropyl fluorophosphatase (DFPase) from the squid Loligo vulgaris is known to effectively hydrolyze DFP and the …

The Histidinol Phosphate Phosphatase Involved in Histidine Biosynthetic Pathway Is Encoded by SCO5208 (hisN) in Streptomyces coelicolor A3(2)

2008

Through the screening of a Streptomyces coelicolor genomic library, carried out in a histidinol phosphate phosphatase (HolPase) deficient strain, SCO5208 was identified as the last unknown gene involved in histidine biosynthesis. SCO5208 is a phosphatase, and it can restore the growth in minimal medium in this HolPase deficient strain when cloned in a high or low copy number vector. Moreover, it shares sequence homology with other HolPases recently identified in Actinobacteria. During this work a second phosphatase, SCO2771, sharing no homologies with SCO5208 and all so far described phosphatases was identified. It can complement HolPase activity mutation only at high copy number. Sequence …

Serine/threonine protein phosphatase PP2A as a relevant target of disulphide stress in acute pancreatitis

2016

Transcriptomic identification of miR-205 target genes potentially involved in metastasis and survival of cutaneous malignant melanoma

2020

AbstractCutaneous melanoma is an aggressive neoplasm and is responsible for the majority of skin cancer deaths. Several miRNAs are involved in melanoma tumor progression. One of them is miR-205, the loss of which contributes to the development of melanoma metastasis. We evaluated whole-genome mRNA expression profiling associated with different miR-205 expression levels in melanoma cells. Differential expression analysis identified 243 differentially expressed transcripts including inositol polyphosphate 5′-phosphatase-like protein-1 (INPPL1) and BTB/POZ Domain-Containing Protein 3 (BTBD3). INPPL1 and BTBD3 were downregulated when melanoma cells expressed miR-205, indicating that these genes…

Effect of rhamnolipids on microbial biomass content and biochemical parameters in soil contaminated with coal tar creosote

2019

AbstractThe objective of the present study was to compare the effect of rhamnolipids on the microbial biomass content and the activity of dehydrogenases (DHA), acid phosphatase (ACP), alkaline phosphatase (ALP), and urease (URE) in soil contaminated with two types of coal tar creosote: type C and type GX-Plus. The experiment was carried out on samples of sandy clay loam under laboratory conditions. Coal tar creosote was added to soil samples at a dose of 0 and 10 g·kg−1 DM, along with rhamnolipids at a dose of 0, 10, 100, and 1000 mg·kg−1 DM. The humidity of the samples was brought to 60% maximum water holding capacity, and the samples were incubated at 20°C. Microbial and biochemical param…

Molecular mechanism of T-cell protein tyrosine phosphatase (TCPTP) activation by mitoxantrone.

2013

T-cell protein tyrosine phosphatase (TCPTP) is a ubiquitously expressed non-receptor protein tyrosine phosphatase. It is involved in the negative regulation of many cellular signaling pathways. Thus, activation of TCPTP could have important therapeutic applications in diseases such as cancer and inflammation. We have previously shown that the α-cytoplasmic tail of integrin α1β1 directly binds and activates TCPTP. In addition, we have identified in a large-scale high-throughput screen six small molecules that activate TCPTP. These small molecule activators include mitoxantrone and spermidine. In this study, we have investigated the molecular mechanism behind agonist-induced TCPTP activation.…

A subunit of eukaryotic translation initiation factor 2α-phosphatase (CreP/PPP1R15B) regulates membrane traffic.

2012

The constitutive reverter of eIF2α phosphorylation (CReP)/PPP1r15B targets the catalytic subunit of protein phosphatase 1 (PP1c) to phosphorylated eIF2α (p-eIF2α) to promote its dephosphorylation and translation initiation. Here, we report a novel role and mode of action of CReP. We found that CReP regulates uptake of the pore-forming Staphylococcus aureus α-toxin by epithelial cells. This function was independent of PP1c and translation, although p-eIF2α was involved. The latter accumulated at sites of toxin attack and appeared conjointly with α-toxin in early endosomes. CReP localized to membranes, interacted with phosphomimetic eIF2α, and, upon overexpression, induced and decorated a pop…

Reaction Rate Modeling in Cryoconcentrated Solutions: Alkaline Phosphatase Catalyzed DNPP Hydrolysis

2000

The hydrolysis of disodium p-nitrophenyl phosphate catalyzed by alkaline phosphatase was chosen as a model to study the kinetics of changes in frozen food products. The initial reaction rate was determined in concentrated sucrose solutions down to -24 degrees C, and the enzymatic characteristics K(M) and V(max) were calculated. The experimental data were compared to the kinetics predicted by assuming that the reaction was viscosity dependent. Indeed, an analysis of the enzymatic reaction demonstrated that both the diffusion of the substrate and the flexibility of the enzyme segments were controlled by the high viscosity of the media. When the temperature was too low for the viscosity to be …