scholarly journals Influence of Subcellular Localization and Functional State on Protein Turnover

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1747
Author(s):  
Roya Yousefi ◽  
Kristina Jevdokimenko ◽  
Verena Kluever ◽  
David Pacheu-Grau ◽  
Eugenio F. Fornasiero
Keyword(s):  
Subcellular Localization ◽  
Functional State ◽  
Protein Turnover ◽  
Protein Localization ◽  
Small Gtpase ◽  
Turnover Rates ◽  
Cellular Behavior ◽  
Two Factors ◽  
Brain Creatine Kinase ◽  
Selection Of

Protein homeostasis is an equilibrium of paramount importance that maintains cellular performance by preserving an efficient proteome. This equilibrium avoids the accumulation of potentially toxic proteins, which could lead to cellular stress and death. While the regulators of proteostasis are the machineries controlling protein production, folding and degradation, several other factors can influence this process. Here, we have considered two factors influencing protein turnover: the subcellular localization of a protein and its functional state. For this purpose, we used an imaging approach based on the pulse-labeling of 17 representative SNAP-tag constructs for measuring protein lifetimes. With this approach, we obtained precise measurements of protein turnover rates in several subcellular compartments. We also tested a selection of mutants modulating the function of three extensively studied proteins, the Ca2+ sensor calmodulin, the small GTPase Rab5a and the brain creatine kinase (CKB). Finally, we followed up on the increased lifetime observed for the constitutively active Rab5a (Q79L), and we found that its stabilization correlates with enlarged endosomes and increased interaction with membranes. Overall, our data reveal that both changes in protein localization and functional state are key modulators of protein turnover, and protein lifetime fluctuations can be considered to infer changes in cellular behavior.

Subcellular Localization of the Small GTPase Rab5a in Resting and Stimulated Human Neurotrophils

1997 ◽  
Vol 230 (2) ◽  
pp. 415
Author(s):  
Francesca Vita ◽  
Maria Rosa Soranzo ◽  
Violetta Borelli ◽  
Paolo Bertoncin ◽  
Giuliano Zabucchi
Keyword(s):  
Subcellular Localization ◽  
Small Gtpase

Spacing, movements, and habitat selection of the river otter in boreal Alberta

1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero
Keyword(s):  
Lontra Canadensis ◽  
Home Ranges ◽  
Adult Males ◽  
Movement Rates ◽  
River Otters ◽  
Aquatic Mammal ◽  
Adult Females ◽  
Two Factors ◽  
Bog Lakes ◽  
Selection Of

Seasonal spacing patterns, home ranges, and movements of river otters (Lontra canadensis) were studied in boreal Alberta by means of radiotelemetry. Adult males occupied significantly larger annual home ranges than adult females. Males' ranges overlapped those of females and also each other's. In winter, home ranges of males shrank and showed less overlap. Otters often associated in groups, the core members typically being adult females with young, or adult males. Otters tended to be more solitary in winter. In winter, movement rates of all sex and age classes were similar, and much reduced for males compared with those in other seasons. These data indicated a strong limiting effect of winter ice on behaviour and dispersion. We tested the hypothesis that otters select water bodies in winter on the basis of the suitability of shoreline substrate and morphology for dens with access both to air and to water under ice. Intensity of selection was greatest in winter, with avoidance of gradually sloping shorelines of sand or gravel. Adults selected bog lakes with banked shores containing semi-aquatic mammal burrows, and lakes with beaver lodges. Subadults selected beaver-impounded streams. Apart from human harvest, winter habitats and food availability in such habitats are likely the two factors most strongly limiting otter density in boreal Alberta.

scholarly journals Phosphorylation by Protein Kinase Cα Regulates RalB Small GTPase Protein Activation, Subcellular Localization, and Effector Utilization

2012 ◽  
Vol 287 (18) ◽  
pp. 14827-14836 ◽  
Author(s):  
Timothy D. Martin ◽  
Natalia Mitin ◽  
Adrienne D. Cox ◽  
Jen Jen Yeh ◽  
Channing J. Der
Keyword(s):  
Protein Kinase ◽  
Subcellular Localization ◽  
Small Gtpase ◽  
Protein Activation ◽  
Protein Kinase Cα

scholarly journals Acceleration in the bilingual acquisition of phonological structure: Evidence from Polish–English bilingual children

2014 ◽  
Vol 18 (4) ◽  
pp. 713-725 ◽  
Author(s):  
MARCO TAMBURELLI ◽  
EIRINI SANOUDAKI ◽  
GARY JONES ◽  
MICHELLE SOWINSKA
Keyword(s):  
Nonword Repetition ◽  
Bilingual Children ◽  
Consonant Clusters ◽  
Phonological Structure ◽  
English Bilingual ◽  
Two Factors ◽  
New Evidence ◽  
Phonological Complexity ◽  
Repetition Task ◽  
Selection Of

This study examines the production of consonant clusters in simultaneous Polish–English bilingual children and in language-matched English monolinguals (aged 7;01–8;11). Selection of the language pair was based on the fact that Polish allows a greater range of consonant clusters than English. A nonword repetition task was devised in order to examine clusters of different types (obstruent-liquid vs. s + obstruent) and in different word positions (initial vs. medial), two factors that play a significant role in repetition accuracy in monolingual acquisition (e.g., Kirk & Demuth, 2005). Our findings show that bilingual children outperformed monolingual controls in the word initial s + obstruent condition. These results indicate that exposure to complex word initial clusters (in Polish) can accelerate the development of less phonologically complex clusters (in English). This constitutes significant new evidence that the facilitatory effects of bilingual acquisition extend to structural phonological domains. The implications that these results have on competing views of phonological organisation and phonological complexity are also discussed.

scholarly journals Modulation of Astrocytes on Mode Selection of Neuron Firing Driven by Electromagnetic Induction

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhongquan Gao ◽  
Zhixuan Yuan ◽  
Zuo Wang ◽  
Peihua Feng
Keyword(s):  
Membrane Potential ◽  
Resting State ◽  
Electromagnetic Induction ◽  
Neuron Model ◽  
Mode Selection ◽  
Neuron Firing ◽  
Two Factors ◽  
Selection Of ◽  
Strong Ability

Both of astrocytes and electromagnetic induction are magnificent to modulate neuron firing by introducing feedback currents to membrane potential. An improved astro-neuron model considering both of the two factors is employed to investigate their different roles in modulation. The mixing mode, defined by combination of period bursting and depolarization blockage, characterizes the effect of astrocytes. Mixing mode and period bursting alternatively appear in parameter space with respect to the amplitude of feedback current on neuron from astrocyte modulation. However, magnetic flux obviously plays a role of neuron firing inhibition. It not only repels the mixing mode but also suppresses period bursting. The mixing mode becomes period bursting mode and even resting state when astrocytes are hyperexcitable. Abnormal activities of astrocytes are capable to induce depolarization blockage to compose the mixing mode together with bursting mode. But electromagnetic induction shows its strong ability of inhibition of neuron firing, which is also illustrated in the bifurcation diagram. Indeed, the combination of the two factors and appropriate choice of parameters show the great potential to control disorder of neuron firing like epilepsy.

Protein turnover during metabolic arrest in turtle hepatocytes: role and energy dependence of proteolysis

1994 ◽  
Vol 266 (4) ◽  
pp. C1028-C1036 ◽  
Author(s):  
S. C. Land ◽  
P. W. Hochachka
Keyword(s):  
Energy Dependence ◽  
Protein Turnover ◽  
Lactate Production ◽  
Significant Inhibition ◽  
Turnover Rates ◽  
Atp Turnover ◽  
Protein Pool ◽  
Chrysemys Picta Bellii ◽  
Metabolic Arrest ◽  
Energy Dependent

Hepatocytes from the western painted turtle (Chrysemys picta bellii) are capable of a coordinated metabolic suppression of 88% during 10 h of anoxia at 25 degrees C. The energy dependence and role of proteolysis in this suppression were assessed in labile ([3H]Phe-labeled) and stable ([14C]Phe-labeled) protein pools. During anoxia, labile protein half-lives increased from 24.7 +/- 3.3 to 34.4 +/- 3.7 h, with stable protein half-lives increasing from 55.6 +/- 3.4 to 109.6 +/- 7.4 h. The total anoxic mean proteolytic suppression for both pools was 36%. On the basis of inhibition of O2 consumption and lactate production rates by cycloheximide and emetine, normoxic ATP-dependent proteolysis required 11.1 +/- 1.7 mumol ATP.g-1.h-1 accounting for 21.8 +/- 1.4% of total cellular metabolism. Under anoxia this was suppressed by 93% to 0.73 +/- 0.43 mumol ATP.g-1.h-1. Summation of this with protein synthesis ATP turnover rates indicated that under anoxia 45% of total ATP turnover rate was directed toward protein turnover. Studies with inhibitors of energy metabolism indicated that the majority of energy dependence was found in the stable protein pool, with no significant inhibition occurring among the more labile proteins. We conclude that proteolysis is largely energy dependent under normoxia, whereas under anoxia there is a shift to a slower overall proteolytic rate that is largely energy independent and represents loss mostly from the labile protein pool.

Economic Comparison of Mechanical and Chemical Weed Control

Weed Science ◽  
1968 ◽  
Vol 16 (3) ◽  
pp. 369-371 ◽  
Author(s):  
David L. Armstrong ◽  
J. K. Leasure ◽  
Mitchell R. Corbin
Keyword(s):  
Weed Control ◽  
Control Method ◽  
Economic Feasibility ◽  
Control Methods ◽  
Net Income ◽  
Small Item ◽  
Mechanical Methods ◽  
Two Factors ◽  
Complex Decision ◽  
Selection Of

The problem in determining the economic feasibility of mechanical, chemical, and combination weed control methods in corn (Zea mays L.) is a complex decision involving many factors. The effects of cost, yield, timeliness, and alternative uses of labor are the factors considered in comparing various methods of weed control in this study. Costs of weed control operations range from $2.84/A for two cultivations to $10.45/A for the most intensive, mechanical-chemical operation studied. Most common weed control methods have costs of approximately $3 to $4/A. Yields range from 83 bu/A for two cultivations to 96 bu/A with the highest cost chemical-mechanical weed control methods. All yields used in this study are supported by agronomic studies and are indexed on the basis of 100 bu/A for weed-free conditions. The consideration of both yields and costs does affect the selection of a weed control method. Considering only these two factors, mechanical methods have a slight advantage over chemical weed control methods. Penalizing mechanical methods because of delay or timeliness characteristics gives chemical methods an advantage by as much as $3.00/A. Alternative uses of labor, even though a common argument in selecting chemical or mechanical methods, is a very small item and has only moderate effects on the changes in net income.

Research on Calculation Method of Alternative Fuel Quantity for Natural Gas Bus

2014 ◽  
Vol 687-691 ◽  
pp. 415-418
Author(s):  
Xiao Li ◽  
Li Liu ◽  
Zhong Xiang Li
Keyword(s):  
Energy Efficiency ◽  
Natural Gas ◽  
Calculation Method ◽  
Calorific Value ◽  
Alternative Fuel ◽  
Correction Coefficient ◽  
Actual Situation ◽  
Two Factors ◽  
Natural Gas Vehicle ◽  
Selection Of

There is no more in-depth research in the amount of alternative between natural gas and tradition fuel. The paper consider two factors about gas calorific value and vehicle level and put forward the fuel calorific value correction coefficient and vehicle energy efficiency correction coefficient. On this basis, the coefficient table and calculation method was established. The paper proved that because of the influence of the factors, equivalent ratio in the range of 1.13~1.67. The method can indicate the gas replacement more scientific and real, because of consider of the actual situation of application of the enterprise.The research can guide the selection of natural gas vehicle reasonable and scientific.

scholarly journals Dual pathways for ribonucleic acid turnover in WI-38 but not in I-cell human diploid fibroblasts.

1981 ◽  
Vol 1 (1) ◽  
pp. 75-81 ◽  
Author(s):  
M Sameshima ◽  
S A Liebhaber ◽  
D Schlessinger
Keyword(s):  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
Protein Turnover ◽  
Rna Turnover ◽  
Turnover Rates ◽  
Diploid Fibroblasts ◽  
Human Diploid Fibroblasts ◽  
Cytoplasmic Rna ◽  
Ribosomal Ribonucleic Acid ◽  
I Cells

The turnover rates of 3H-labeled 18S ribosomal ribonucleic acid (RNA), 28S ribosomal RNA, transfer RNA, and total cytoplasmic RNA were very similar in growing WI-38 diploid fibroblasts. The rate of turnover was at least twofold greater when cell growth stopped due to cell confluence, 3H irradiation, or treatment with 20 mM NaN3 or 2 mM NaF. In contrast, the rate of total 3H-protein turnover was the same in growing and nongrowing cells. Both RNA and protein turnovers were accelerated at least twofold in WI-38 cells deprived of serum, and this increase in turnover was inhibited by NH4Cl. These results are consistent with two pathways for RNA turnover, one of them being nonlysosomal and the other being lysosome mediated (NH4Cl sensitive), as has been suggested for protein turnover. Also consistent with the notion of two pathways for RNA turnover were findings with I-cells, which are deficient for many lysosomal enzymes, and in which all RNA turnover was nonlysosomal (NH4Cl resistant).

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