Search results for "Transporters"

The cytoplasmic PASC domain of the sensor kinase DcuS of Escherichia coli : role in signal transduction, dimer formation, and DctA interaction

2013

The cytoplasmic PAS(C) domain of the fumarate responsive sensor kinase DcuS of Escherichia coli links the transmembrane to the kinase domain. PAS(C) is also required for interaction with the transporter DctA serving as a cosensor of DcuS. Earlier studies suggested that PAS(C) functions as a hinge and transmits the signal to the kinase. Reorganizing the PAS(C) dimer interaction and, independently, removal of DctA, converts DcuS to the constitutive ON state (active without fumarate stimulation). ON mutants were categorized with respect to these two biophysical interactions and the functional state of DcuS: type I-ON mutations grossly reorganize the homodimer, and decrease interaction with Dct…

Multi-Functional Nanogels for Tumor Targeting and Redox-Sensitive Drug and siRNA Delivery

2016

(1) Background: A new family of nanosystems able to discern between normal and tumor cells and to release a therapeutic agent in controlled way were synthetized by e-beam irradiation. This technique permits to obtain biocompatible, sterile, carboxyl-functionalized polyvinylpyrrolidone (PVP-co-acrylic acid) nanogels (NGs); (2) Methods: Here, we performed a targeting strategy based on the recognition of over-expressed proteins on tumor cells, like the folate receptor. The selective targeting was demonstrated by co-culture studies and flow cytometry analysis, using folate conjugated NGs. Moreover, nanoparticles were conjugated to a chemotherapeutic drug or to a pro-apoptotic siRNA through a gl…

Identification of novel mutations in the ABCA12 gene, c.1857delA and c.5653–5655delTAT, causing harlequin ichthyosis

2013

Abstract Harlequin ichthyosis (HI) is a severe autosomal recessive developmental disorder of the skin that is frequently but not always fatal in the first few days of life. In HI, mutations in both ABCA12 gene alleles must have a severe impact on protein function and most mutations are truncating. The presence of at least one nontruncating mutation (predicting a residual protein function) usually causes a less severe congenital ichthyosis (lamellar ichthyosis or congenital ichthyosiform erythroderma). Here we report on a girl with severe HI diagnosed by prenatal ultrasound at 33 5/7 week gestation. Ultrasound findings included ectropion, eclabium, deformed nose, hands and feet, joint contra…

Editorial: Relevance of Steroid Biosynthesis, Metabolism and Transport in Pathophysiology and Drug Discovery

2019

In Vitro Analysis of the Two-Component System MtrB-MtrA from Corynebacterium glutamicum▿ †

2007

ABSTRACT The two-component system MtrBA is involved in the osmostress response of Corynebacterium glutamicum . MtrB was reconstituted in a functionally active form in liposomes and showed autophosphorylation and phosphatase activity. In proteoliposomes, MtrB activity was stimulated by monovalent cations used by many osmosensors for the detection of hypertonicity. Although MtrB was activated by monovalent cations, they lead in vitro to a general stabilization of histidine kinases and do not represent the stimulus for MtrB to sense hyperosmotic stress.

Functioning of DcuC as the C 4 -Dicarboxylate Carrier during Glucose Fermentation by Escherichia coli

1999

ABSTRACT The dcuC gene of Escherichia coli encodes an alternative C 4 -dicarboxylate carrier (DcuC) with low transport activity. The expression of dcuC was investigated. dcuC was expressed only under anaerobic conditions; nitrate and fumarate caused slight repression and stimulation of expression, respectively. Anaerobic induction depended mainly on the transcriptional regulator FNR. Fumarate stimulation was independent of the fumarate response regulator DcuR. The expression of dcuC was not significantly inhibited by glucose, assigning a role to DcuC during glucose fermentation. The inactivation of dcuC increased fumarate-succinate exchange and fumarate uptake by DcuA and DcuB, suggesting a…

Defense Responses of Fusarium oxysporum to 2,4-Diacetylphloroglucinol, a Broad-Spectrum Antibiotic Produced by Pseudomonas fluorescens

2004

A collection of 76 plant-pathogenic and 41 saprophytic Fusarium oxysporum strains was screened for sensitivity to 2,4-diacetylphloroglucinol (2,4-DAPG), a broad-spectrum antibiotic produced by multiple strains of antagonistic Pseudomonas fluorescens. Approximately 17% of the F. oxysporum strains were relatively tolerant to high 2,4-DAPG concentrations. Tolerance to 2,4-DAPG did not correlate with the geographic origin of the strains, formae speciales, intergenic spacer (IGS) group, or fusaric acid production levels. Biochemical analysis showed that 18 of 20 tolerant F. oxysporum strains were capable of metabolizing 2,4-DAPG. For two tolerant strains, analysis by mass spectrometry indicated…

Multiple Pluripotent Stem Cell Markers in Human Anaplastic Thyroid Cancer: The Putative Upstream Role of SOX2

2013

Anaplastic thyroid carcinoma (ATC) is a rare and aggressive endocrine tumor with highly undifferentiated morphology. It has been suggested that cancer stem cells (CSCs) might play a central role in ATC. The objectives of this study were (i) to characterize CSCs from ex vivo ATC specimens by investigating the expression of several pluripotent stem cell markers, and (ii) to evaluate in vitro drug resistance modifications after specific CSC transcription factor switch-off.In ex vivo experiments, eight formalin-fixed, paraffin-embedded ATC specimens were analyzed by reverse-transcription and real-time quantitative PCR and immunohistochemistry. In in vitro experiments using ATC SW1736 cells, the…

Silymarin and Cancer: A Dual Strategy in Both in Chemoprevention and Chemosensitivity

2020

Silymarin extracted from milk thistle consisting of flavonolignan silybin has shown chemopreventive and chemosensitizing activity against various cancers. The present review summarizes the current knowledge on the potential targets of silymarin against various cancers. Silymarin may play on the system of xenobiotics, metabolizing enzymes (phase I and phase II) to protect normal cells against various toxic molecules or to protect against deleterious effects of chemotherapeutic agents on normal cells. Furthermore, silymarin and its main bioactive compounds inhibit organic anion transporters (OAT) and ATP-binding cassettes (ABC) transporters, thus contributing to counteracting potential chemor…

Analysis of the MHC Class I Antigen Presentation Machinery in Human Embryonal Carcinomas: Evidence for Deficiencies in TAP, LMP and MHC Class I Expre…

1998

The expression of the major histocompatibility complex (MHC) class I antigens is suppressed in early post-implantation embryonic cells as well as in embryonal carcinoma (EC) cells, but could be upregulated by treatment with interferon (IFN)-gamma or retinoic acid. In a number of human and murine tumours, defects in the expression of the different components of the MHC class I antigen processing machinery, such as the proteasomal subunits LMP-2 and LMP-7 and the peptide transporters TAP-1 and TAP-2, account for impaired MHC class I surface expression. Here, we analysed the constitutive and IFN-gamma regulated mRNA and protein expression of the LMP, TAP and MHC class I molecules in the human …