Search results for "PHOSPHATASE"
showing 10 items of 499 documents
Illuminating a Phytochrome Paradigm – a Light-Activated Phosphatase in Two-Component Signaling Uncovered
2020
ABSTRACTBacterial phytochrome photoreceptors usually belong to two-component signaling systems which transmit environmental stimuli to a response regulator through a histidine kinase domain. Phytochromes switch between red light-absorbing and far-red light-absorbing states. Despite exhibiting extensive structural responses during this transition, the model bacteriophytochrome fromDeinococcus radiodurans(DrBphP) lacks detectable kinase activity. Here, we resolve this long-standing conundrum by comparatively analyzing the interactions and output activities of DrBphP and a bacteriophytochrome fromAgrobacterium fabrum(AgP1). Whereas AgP1 acts as a conventional histidine kinase, we identify DrBp…
Alginate/silica composite hydrogel as a potential morphogenetically active scaffold for three-dimensional tissue engineering
2013
Pursuing our aim to develop a biomimetic synthetic scaffold suitable for tissue engineering, we embedded bone cells, osteoblast-related SaOS-2 cells and osteoclast-like RAW 264.7 cells, into beads, formed of a Na-alginate-based or a silica-containing Na-alginate-based hydrogel matrix. The beads were incubated either separately (only one cell line in a culture dish) or co-incubated (SaOS-2-containing beads and RAW 264.7 beads). The alginate and alginate/silica hydrogel matrices were found not to impair the viability of the encapsulated cells. In these matrices the SaOS-2 cells retain their capacity to synthesize hydroxyapatite crystallites. The mechanical properties, including surface roughn…
Sensing of O 2 and nitrate by bacteria: alternative strategies for transcriptional regulation of nitrate respiration by O 2 and nitrate
2020
Many bacteria are able to use O2 and nitrate as alternative electron acceptors for respiration. Strategies for regulation in response to O2 and nitrate can vary considerably. In the paradigmatic system of E. coli (and γ-proteobacteria), regulation by O2 and nitrate is established by the O2 -sensor FNR and the two-component system NarX-NarL (for nitrate regulation). Expression of narGHJI is regulated by the binding of FNR and NarL to the promoter. A similar strategy by individual regulation in response to O2 and nitrate is verified in many genera by the use of various types of regulators. Otherwise, in the soil bacteria Bacillus subtilis (Firmicutes) and Streptomyces (Actinobacteria), nitrat…
Control of the bifunctional O 2 ‐sensor kinase NreB of Staphylococcus carnosus by the nitrate sensor NreA: Switching from kinase to phosphatase state
2019
The NreB-NreC two-component system of Staphylococcus carnosus for O2 sensing cooperates with the accessory nitrate sensor NreA in the NreA-NreB-NreC system for coordinated sensing and regulation of nitrate respiration by O2 and nitrate. ApoNreA (NreA in the absence of nitrate) interacts with NreB and inhibits NreB autophosphorylation (and activation). NreB contains the phosphatase motif DxxxQ. The present study shows that NreB on its own was inactive for the dephosphorylation of the phosphorylated response regulator NreC (NreC-P), but co-incubation with NreB and NreA stimulated NreC-P dephosphorylation. Either the presence of NreA · NO 3 - instead of apoNreA or mutation of the phosphatase m…
Nitensidine A, a guanidine alkaloid from Pterogyne nitens, is a novel substrate for human ABC transporter ABCB1.
2014
The Pterogyne nitens (Fabaceae) tree, native to South America, has been found to produce guanidine alkaloids as well as bioactive flavonols such as kaempferol, quercetin, and rutin. In the present study, we examined the possibility of interaction between human ATP-binding cassette (ABC) transporter ABCB1 and four guanidine alkaloids isolated from P. nitens (i.e., galegine, nitensidine A, pterogynidine, and pterogynine) using human T cell lymphoblast-like leukemia cell line CCRF-CEM and its multi-drug resistant (MDR) counterpart CEM/ADR5000. In XTT assays, CEM/ADR5000 cells were resistant to the four guanidine alkaloids compared to CCRF-CEM cells, although the four guanidine alkaloids exhibi…
The Arabidopsis heavy metal P-type ATPase HMA5 interacts with metallochaperones and functions in copper detoxification of roots
2005
*† ‡ § Summary Since copper (Cu) is essential in key physiological oxidation reactions, organisms have developed strategies for handling Cu while avoiding its potentially toxic effects. Among the tools that have evolved to cope with Cu is a network of Cu homeostasis factors such as Cu-transporting P-type ATPases that play a key role in transmembrane Cu transport. In this work we present the functional characterization of an Arabidopsis Cutransporting P-type ATPase, denoted heavy metal ATPase 5 (HMA5), and its interaction with Arabidopsis metallochaperones. HMA5 is primarily expressed in roots, and is strongly and specifically induced by Cu in whole plants. We have identified and characteriz…
Acid sensitivity of neomycin-resistant mutants ofOenococcus oeni: a relationship between reduction of ATPase activity and lack of malolactic activity
1999
Mutants of Oenococcus oeni were isolated as spontaneous neomycin-resistant mutants. Three of these mutants harbored a significantly reduced ATPase activity that represented 50% of that of the wild-type strain. Their growth rates were also impaired at pH 5.3 (46-86% of the wild-type level). However, the profiles of sugar consumption appeared identical to those of the parental strain. At pH 3.2, all the mutant strains failed to grow and a drastic decrease in viability was observed after an acid shock. Surprisingly, all the isolated mutants were devoid of malolactic activity. These results suggest that the ATPase and malolactic activities of O. oeni are linked to each other and play a crucial …
Isoquercitrin and polyphosphate co-enhance mineralization of human osteoblast-like SaOS-2 cells via separate activation of two RUNX2 cofactors AFT6 a…
2014
Isoquercitrin, a dietary phytoestrogen, is a potential stimulator of bone mineralization used for prophylaxis of osteoporotic disorders. Here we studied the combined effects of isoquercitrin, a cell membrane permeable 3-O-glucoside of quercetin, and polyphosphate [polyP], a naturally occurring inorganic polymer inducing bone formation, on mineralization of human osteoblast-like SaOS-2 cells. Both compounds isoquercitrin and polyP induce at non-toxic concentrations the mineralization process of SaOS-2 cells. Co-incubation experiments revealed that isoquercitrin (at 0.1 and 0.3μM), if given simultaneously with polyP (as Ca(2+) salt; at 3, 10, 30 and 100μM) amplifies the mineralization-enhanci…
Customised next-generation sequencing multigene panel to screen a large cohort of individuals with chromatin-related disorder
2020
BackgroundThe regulation of the chromatin state by epigenetic mechanisms plays a central role in gene expression, cell function, and maintenance of cell identity. Hereditary disorders of chromatin regulation are a group of conditions caused by abnormalities of the various components of the epigenetic machinery, namely writers, erasers, readers, and chromatin remodelers. Although neurological dysfunction is almost ubiquitous in these disorders, the constellation of additional features characterizing many of these genes and the emerging clinical overlap among them indicate the existence of a community of syndromes. The introduction of high-throughput next generation sequencing (NGS) methods f…
Age affects myosin relaxation states in skeletal muscle fibers of female but not male mice
2018
The recent discovery that myosin has two distinct states in relaxed muscle–disordered relaxed (DRX) and super-relaxed (SRX)–provides another factor to consider in our fundamental understanding of the aging mechanism in skeletal muscle, since myosin is thought to be a potential contributor to dynapenia (age-associated loss of muscle strength independent of atrophy). The primary goal of this study was to determine the effects of age on DRX and SRX states and to examine their sex specificity. We have used quantitative fluorescence microscopy of the fluorescent nucleotide analog 2′/3′-O-(N-methylanthraniloyl) ATP (mantATP) to measure single-nucleotide turnover kinetics of myosin in skinned skel…