scholarly journals Structures of human dual oxidase 1 complex in low-calcium and high-calcium states

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing-Xiang Wu ◽  
Rui Liu ◽  
Kangcheng Song ◽  
Lei Chen
Keyword(s):  
Hydrogen Peroxide ◽  
Calcium Ions ◽  
Transmembrane Domain ◽  
Protein Complexes ◽  
Biological Processes ◽  
Subunit Interactions ◽  
Low Calcium ◽  
High Calcium ◽  
Ef Hand ◽  
Dual Oxidase

AbstractDual oxidases (DUOXs) produce hydrogen peroxide by transferring electrons from intracellular NADPH to extracellular oxygen. They are involved in many crucial biological processes and human diseases, especially in thyroid diseases. DUOXs are protein complexes co-assembled from the catalytic DUOX subunits and the auxiliary DUOXA subunits and their activities are regulated by intracellular calcium concentrations. Here, we report the cryo-EM structures of human DUOX1-DUOXA1 complex in both high-calcium and low-calcium states. These structures reveal the DUOX1 complex is a symmetric 2:2 hetero-tetramer stabilized by extensive inter-subunit interactions. Substrate NADPH and cofactor FAD are sandwiched between transmembrane domain and the cytosolic dehydrogenase domain of DUOX. In the presence of calcium ions, intracellular EF-hand modules might enhance the catalytic activity of DUOX by stabilizing the dehydrogenase domain in a conformation that allows electron transfer.

scholarly journals Structure and mechanism of human dual oxidase 1 complex

2020 ◽  
Author(s):  
Jing-Xiang Wu ◽  
Rui Liu ◽  
Kangcheng Song ◽  
Lei Chen
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Calcium Ions ◽  
Transmembrane Domain ◽  
Protein Complexes ◽  
Biological Processes ◽  
Subunit Interactions ◽  
High Calcium ◽  
Ef Hand ◽  
Dual Oxidase

AbstractDual oxidases (DUOXs) produce hydrogen peroxide by transferring electrons from intracellular NADPH to extracellular oxygen. They are involved in many crucial biological processes and human diseases, especially in thyroid diseases. DUOXs are protein complexes co-assembled from the catalytic DUOX subunits and the auxiliary DUOXA subunits and their activities are regulated by intracellular calcium concentrations. Here, we report the cryo-EM structures of human DUOX1-DUOXA1 complex in both high-calcium and low-calcium states. These structures reveal the DUOX1 complex is a symmetric 2:2 hetero-tetramer stabilized by extensive inter-subunit interactions. Substrate NADPH and cofactor FAD are sandwiched between transmembrane domain and the cytosolic dehydrogenase domain of DUOX. In the presence of calcium ions, intracellular EF-hand modules enhance the catalytic activity of DUOX by stabilizing the dehydrogenase domain in a position that is optimal for electron transfer.

Computational insights into the calcium ions role in protein-glycosaminoglycan systems

2021 ◽  
Author(s):  
Małgorzata M Kogut ◽  
Martyna Maszota-Zieleniak ◽  
Mateusz Marcisz ◽  
Sergey Samsonov
Keyword(s):  
Extracellular Matrix ◽  
Calcium Ions ◽  
Vital Role ◽  
Biological Processes ◽  
Periodic Linear

Glycosaminoglycans (GAGs) are anionic periodic, linear polysaccharides which are composed of periodic disaccharide units. They play a vital role in many biological processes ongoing in the extracellular matrix. In terms...

Effect of phorbol myristate acetate on secretion of parathyroid hormone

1988 ◽  
Vol 254 (1) ◽  
pp. E63-E70 ◽  
Author(s):  
J. J. Morrissey
Keyword(s):  
Protein Kinase C ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Membrane Fraction ◽  
Hormone Secretion ◽  
Myristate Acetate ◽  
Kinase C ◽  
Low Calcium ◽  
Protein Kinase C Activity ◽  
High Calcium

The influence of phorbol myristate acetate (PMA), an activator of protein kinase c, on the secretion of parathyroid hormone from collagenase-dispersed bovine parathyroid cells was tested. The cells were incubated at low (0.5 mM) or high (2.0 mM) concentrations of calcium in the medium, and the hormone secreted into the medium was measured by a radioimmunoassay that recognizes both intact and C-terminal fragments of hormone. At low calcium, the secretory rate averaged 32 +/- 3.8 ng.h-1.(10(5) cells)-1. The addition of 1.6 microM PMA did not affect secretion. At high calcium there was a significant suppression of secretion by 38% to 19.8 +/- 3 ng.h-1.(10(5) cells)-1. The addition of 1.6 microM PMA significantly stimulated hormone secretion to 35.8 +/- 8 ng.h-1.(10(5) cells)-1, a rate indistinguishable from low calcium. This stimulatory effect of PMA at high calcium was seen at PMA concentrations as low as 1.6 nM, did not occur with a biologically inactive 4 alpha-isomer of phorbol ester, and was independent of changes in cellular adenosine 3',5'-cyclic monophosphate levels. Examination of 32P-labeled phosphoproteins by two-dimensional gel electrophoresis revealed acidic proteins of approximately 20,000 and 100,000 Da that were phosphorylated at low and high calcium + 1.6 microM PMA but not at high calcium alone. The protein kinase c activity associated with the membrane fraction of parathyroid cells significantly decreased 40% when the cells were incubated at high vs. low calcium. The data suggest that calcium may regulate parathyroid hormone secretion through changes in protein kinase c activity of the membrane fraction of the cell and protein phosphorylation.

Fibrinogen Bern I: A Hereditary Fibrinogen Variant With Defective Conformational Stabilization By Calcium Ions

1981 ◽  
Author(s):  
C Rupp ◽  
C Kuyas ◽  
A Häberli ◽  
M Furlan ◽  
E A Beck
Keyword(s):  
Calcium Ions ◽  
Gel Electrophoresis ◽  
Calcium Binding ◽  
Negative Charge ◽  
Fibrinopeptide A ◽  
Isoelectric Focussing ◽  
High Calcium ◽  
Two Generations ◽  
Polypeptide Chains ◽  
Conformational Stabilization

Inherited hypodysfibrinogenemia (fibrinogen Bern I) was found in four members (two generations) of a family with no haemorrhagic or thrombotic history. Fibrin aggregation curves (350 nm, 37°C) with patient plasma or purified fibrinogen Bern I, after addition of thrombin, were normal at high calcium concentrations (5mM) but delayed at lower calcium concentrations (≤0.lmM). The release of fibrinopeptide A was normal. Whereas the polypeptide chains of fibrinogen Bern I were indistinguishable from normal fibrinogen by SDS-gel-electrophoresis, an abnormal γ-chain with a decreased negative charge was found by isoelectric focussing.Plasmic degradation o| normal fibrinogen, in the presence of calcium (≥ImM), results in only one terminal D fragment which is stabilized by calcium against further degradation of γ-chains. In contrast, degradation of fibrinogen Bern I, under the same conditions, yielded at least two additional smaller D fragments. In conclusion, fibrinogen Bern I is characterized by defective calcium binding in the D domain of the γ-chain.

scholarly journals Secretion and degradation of parathormone as a function of intracellular maturation of hormone pools

1979 ◽  
Vol 83 (3) ◽  
pp. 521-528 ◽  
Author(s):  
JJ Morrissey ◽  
DV Cohn
Keyword(s):  
Cyclic Amp ◽  
Half Life ◽  
Calcium Concentration ◽  
Hormone Secretion ◽  
Ionized Calcium ◽  
Dibutyryl Cyclic Amp ◽  
Low Calcium ◽  
High Calcium ◽  
Parathormone Secretion

The biosynthesis, processing, and secretion of parthormone and the effect of calcium on these processes were measured in dispersed porcine parthyroid cells incubated with [(35)S]methionine. Proparathormone was detected at 10 min, the earliest time measured, and was rapidly and apparently quantitatively converted to parathormone. The half-life of the prohomormone pool was 15 min. Secretion of parathormone was detected by 20 min. In pulse-chase experiments there was a period between 20 and 40 min during which the wave of newly-synthesized parathormone was secreted. After 40 min during little additional radioactive hormone was secreted, but dibutyryl cyclic AMP, an agent that can mobilize stored parathormone, when added to the incubation mixtures enhanced radioactive parathormone secretion but only after 60 min, although it increased net hormone secretion as determined by radioimmunoassay to the same extent at all times studied. When the ionized calcium concentration of the medium was lowered, more radioactive hormone was secreted at all times but the effect was greatest on that hormone that was synthesized less than 60 min previously ; however, net hormone secretion in contrast to radioactive hormone was enhanced equally at all intervals. These data could mean that the refractoriness to secretion of parathormone 40-60 min of age was related to maturation of secretory container preparatory to storage. Low calcium (0.5 mM) stimulated hormone secretion up to fivefold compared to high calcium (3.0 mM) but did not affect synthesis of parathormone or proparathormne or conversion of the latter to hormone. During processing at least 70 percent of the intracellular parathormone was lost, presumably through proteolysis and this degradation was greater at high calcium. These data have been interpreted in light of the concept that two secretable pools of parathormone exist within the parathyroid.

Electrokinetic Phenomena and Surface Characteristics of Fly Ash Particles

1984 ◽  
Vol 43 ◽  
Author(s):  
R. I. A. Malek ◽  
D. M. Roy
Keyword(s):  
Fly Ash ◽  
Surface Characteristics ◽  
Ionic Species ◽  
Point Of Zero Charge ◽  
Fly Ashes ◽  
Electrokinetic Phenomena ◽  
Zeta Potentials ◽  
Low Calcium ◽  
High Calcium

AbstractThe zeta-potentials of two fly ashes were studied (high-calcium and low-calcium). It was found that they possess a point of charge reversal at pH = 10.5 to 12. The point of zero charge (low-calcium fly ash) was found to be at pH = 5. Furthermore, it shifted to more acidic values after the fly ash is aged in several calcium-containing solutions. The surficial changes that could happen when mixing fly ashes with cement and concrete were further evaluated by aging fly ashes in different solutions: Ca(OH)2, CaSO4·2H2O, NaOH and water solutions. Information from analyses for different ionic species in the solutions and characterization of the solid residues (XRD and SEM) was used in tentative explanations for the different behavior of the two types of fly ash in cementitious mixtures and concrete.

scholarly journals Every laboratory with a fluorescence microscope should consider counting molecules

2014 ◽  
Vol 25 (10) ◽  
pp. 1545-1548 ◽  
Author(s):  
Valerie C. Coffman ◽  
Jian-Qiu Wu
Keyword(s):  
Mathematical Modeling ◽  
Fluorescence Microscopy ◽  
Protein Complexes ◽  
The State ◽  
Fluorescence Microscope ◽  
Cellular Structures ◽  
Biological Processes ◽  
Protein Molecules ◽  
Parameter Values

Protein numbers in cells determine rates of biological processes, influence the architecture of cellular structures, reveal the stoichiometries of protein complexes, guide in vitro biochemical reconstitutions, and provide parameter values for mathematical modeling. The purpose of this essay is to increase awareness of methods for counting protein molecules using fluorescence microscopy and encourage more cell biologists to report these numbers. We address the state of the field in terms of utility and accuracy of the numbers reported and point readers to references for details of specific techniques and applications.

Hyperoxia and self- or neutrophil-generated O2 metabolites inactivate xanthine oxidase

1988 ◽  
Vol 65 (5) ◽  
pp. 2349-2353 ◽  
Author(s):  
L. S. Terada ◽  
C. J. Beehler ◽  
A. Banerjee ◽  
J. M. Brown ◽  
M. A. Grosso ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Xanthine Oxidase ◽  
Superoxide Anion ◽  
Hypochlorous Acid ◽  
Control Mechanism ◽  
Xanthine Dehydrogenase ◽  
Biological Processes ◽  
Lung Endothelial Cells ◽  
Cellular Control

Xanthine oxidase (XO) and xanthine dehydrogenase (XD) activities decreased in lungs isolated from rats and cultured lung endothelial cells that had been exposed to hyperoxia. Purified XO activity also decreased after addition of a variety of chemically generated O2 metabolite species (superoxide anion, hydrogen peroxide, hydroxyl radical, or hypochlorous acid), hypoxanthine, or stimulated neutrophils in vitro. XO inactivation by chemically, self-, or neutrophil-generated O2 metabolites was decreased by simultaneous addition of various O2 metabolite scavengers but not their inactive analogues. Since XO appears to contribute to a variety of biological processes and diseases, hyperoxia- or O2 metabolite-mediated decreases in XO activity may be an important cellular control mechanism.

Dual oxidase (DUOX) system genes defects in Children with Congenital Hypothyroidism

Endocrinology ◽  
2021 ◽  
Author(s):  
Fengqi Wang ◽  
Li Xiaole ◽  
Ruixin Ma ◽  
Dehua Zhao ◽  
Shiguo Liu
Keyword(s):  
Congenital Hypothyroidism ◽  
Functional Domain ◽  
Target Region ◽  
Pathogenic Variants ◽  
Significant Difference ◽  
Ef Hand ◽  
Dual Oxidase ◽  
Variation Rate ◽  
Relationship Of

Abstract Purpose The objectives of this study were to analyze the distribution of Dual oxidase (DUOX) system genes (containing DUOX2, DUOX1, DUOXA2 and DUOXA1) variants in children with congenital hypothyroidism and their phenotypes. Methods Target region sequencing technology was performed on DUOX system genes among 606 congenital hypothyroidism (CH) subjects covering all the exon and intron regions. Detailed clinical data were collected for statistical analysis. Results A total of 95 suspected pathogenic variants were detected in the DUOX system genes, showing a 39.11% rate in variant carrying (237/606). DUOX2 was with the highest rate in this study. There were statistical difference in maximum adjusted dose and current dose of L-T4 between the DUOX system genes non-mutated group with the mutated group (p<0.001; p<0.001). The cases in DUOX system genes mutated group were more likely to develop into transient CH (χ 2 = 23.155, p<0.001) and more likely to manifested as goiter or gland-in-situ (χ 2 = 66.139, p<0.001). In addition, there was no significant difference in clinical characteristics between DUOX system genes mono-allelic and non mono-allelic. Although 20% of the variants affected the functional domain regions (EF hand, and FAD and NADPH binding sites), there was no significant effect on the phenotype severity whether the variation is located in the functional domain regions. Conclusions Our results showed the high variation rate of DUOX2 in the DUOX system genes among the Chinese CH patients. And the complex genotype-phenotype relationship of DUOX system genes broadened the understanding of CH phenotype spectrum.

Electrotonic and chemical effects on minimal gradient requirements for cardiac muscle

1962 ◽  
Vol 202 (2) ◽  
pp. 245-248 ◽  
Author(s):  
Junji Ushiyama ◽  
Chandler McC. Brooks
Keyword(s):  
Cardiac Muscle ◽  
Chemical Effects ◽  
Low Calcium ◽  
High Calcium ◽  
Minimal Gradient

The thresholds to rectangular pulses and the minimal gradient requirements for excitation of trabecular muscles from dog hearts were determined. Catelectrotonus lowered thresholds and shortened the minimal gradient or lambda (λ). Anelectrotonus raised thresholds and greatly prolonged lambda. Low calcium lowered threshold and increased lambda, whereas high calcium raised the threshold and shortened lambda. Quinidine and dinitrophenol had little effect on threshold but prolonged lambda. Cyanide also had little effect on threshold but shortened lambda. Urethan and cocaine slightly raised thresholds and shortened lambda. There is thus no correlation between changes in threshold and changes in minimal gradient (λ). The significance of lambda is not known.

Sign in / Sign up

Export Citation Format

Share Document