The Driving Force of Alpha-Synuclein Insertion and Amyloid Channel Formation in the Plasma Membrane of Neural Cells: Key Role of Ganglioside- and Cholesterol-Binding Domains

2013 ◽  
pp. 15-26 ◽  
Author(s):  
Jacques Fantini ◽  
Nouara Yahi
Keyword(s):  
Plasma Membrane ◽  
Driving Force ◽  
Alpha Synuclein ◽  
Neural Cells ◽  
Channel Formation ◽  
Binding Domains ◽  
Cholesterol Binding

scholarly journals Plasma membrane ion permeability induced by mutant alpha-synuclein contributes to the degeneration of neural cells

2006 ◽  
Vol 97 (4) ◽  
pp. 1071-1077 ◽  
Author(s):  
Katsutoshi Furukawa ◽  
Michiko Matsuzaki-Kobayashi ◽  
Takafumi Hasegawa ◽  
Akio Kikuchi ◽  
Naoto Sugeno ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Alpha Synuclein ◽  
Neural Cells ◽  
Ion Permeability

Time-dependent modulation of capacitative Ca2+ entry signals by plasma membrane Ca2+ pump in endothelium

1998 ◽  
Vol 274 (4) ◽  
pp. C1117-C1128 ◽  
Author(s):  
Andrey Klishin ◽  
Marina Sedova ◽  
Lothar A. Blatter
Keyword(s):  
Plasma Membrane ◽  
Driving Force ◽  
Vascular Endothelial Cells ◽  
Time Dependent ◽  
Vascular Endothelial ◽  
Constant Rate ◽  
Intracellular Ca ◽  
Initial Peak ◽  
Plateau Level

In vascular endothelial cells, depletion of intracellular Ca2+ stores elicited capacitative Ca2+ entry (CCE) that resulted in biphasic changes of intracellular Ca2+ concentration ([Ca2+]i) with a rapid initial peak of [Ca2+]ifollowed by a gradual decrease to a sustained plateau level. We investigated the rates of Ca2+entry, removal, and sequestration during activation of CCE and their respective contributions to the biphasic changes of [Ca2+]i. Ca2+ buffering by mitochondria, removal by Na+/Ca2+exchange, and a fixed electrical driving force for Ca2+ (voltage-clamp experiments) had little effect on the CCE signal. The rates of entry of Mn2+ and Ba2+, used as unidirectional substitutes for Ca2+ entry through the CCE pathway, were constant and did not follow the concomitant changes of [Ca2+]i. Pharmacological inhibition of the plasma membrane Ca2+ pump, however, abolished the secondary decay phase of the CCE transient. The disparity between the biphasic changes of [Ca2+]iand the constant rate of Ca2+entry during CCE was the result of a delayed, Ca2+-dependent activation of the pump. These results suggest an important modulatory role of the plasma membrane Ca2+ pump in the net cellular gain of Ca2+ during CCE.

Versatile role of the yeast ubiquitin ligase Rsp5p in intracellular trafficking

2008 ◽  
Vol 36 (5) ◽  
pp. 791-796 ◽  
Author(s):  
Naima Belgareh-Touzé ◽  
Sébastien Léon ◽  
Zoi Erpapazoglou ◽  
Marta Stawiecka-Mirota ◽  
Danièle Urban-Grimal ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Ubiquitin Ligase ◽  
Protein Trafficking ◽  
Adaptor Proteins ◽  
Binding Domains ◽  
Independent Functions ◽  
Membrane Protein Trafficking ◽  
Ubiquitin Ligase E3

The ubiquitin ligase (E3) Rsp5p is the only member of the Nedd (neural-precursor-cell-expressed, developmentally down-regulated) 4 family of E3s present in yeast. Rsp5p has several proteasome-independent functions in membrane protein trafficking, including a role in the ubiquitination of most plasma membrane proteins, leading to their endocytosis. Rsp5p is also required for the ubiquitination of endosomal proteins, leading to their sorting to the internal vesicles of MVBs (multivesicular bodies). Rsp5p catalyses the attachment of non-conventional ubiquitin chains, linked through ubiquitin Lys-63, to some endocytic and MVB cargoes. This modification appears to be required for efficient sorting, possibly because these chains have a greater affinity for the ubiquitin-binding domains present within endocytic or MVB sorting complexes. The mechanisms involved in the recognition of plasma membrane and MVB substrates by Rsp5p remain unclear. A subset of Rsp5/Nedd4 substrates have a ‘PY motif’ and are recognized directly by the WW (Trp-Trp) domains of Rsp5p. Most Rsp5p substrates do not carry PY motifs, but some may depend on PY-containing proteins for their ubiquitination by Rsp5p, consistent with the latter's acting as specificity factors or adaptors. As in other ubiquitin-conjugating systems, these adaptors are also Rsp5p substrates and undergo ubiquitin-dependent trafficking. In the present review, we discuss recent examples illustrating the role of Rsp5p in membrane protein trafficking and providing new insights into the regulation of this E3 by adaptor proteins.

Role of membrane potential in hypoxic inhibition of L-arginine uptake by lung endothelial cells

1997 ◽  
Vol 272 (1) ◽  
pp. L78-L84 ◽  
Author(s):  
S. I. Zharikov ◽  
H. Herrera ◽  
E. R. Block
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Membrane Potential ◽  
Driving Force ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Arginine Transport ◽  
Lung Endothelial Cells ◽  
Reversible Time

System y+ accounts for the majority of L-arginine transport by pulmonary artery endothelial cells (PAEC). Given that membrane potential is a driving force for transport via system y+, we examined the hypothesis that hypoxia inhibits this transport by decreasing membrane potential. Porcine PAEC or plasma membrane vesicles derived from these cells were exposed to normoxia (room air-5% CO2) or hypoxia (0% O2-95% N2-5% CO2). After exposure, L-[3H]arginine transport and/or accumulation of the lipophilic cation [3H]tetraphenylphosphonium, a quantitative sensor of changes in cell membrane potential, were measured. Hypoxia caused reversible time-dependent decrease in L-arginine transport and membrane potential in PAEC and in plasma membrane vesicles. Comparable decreases in membrane potential and L-arginine transport by PAEC were also observed after depolarization induced by KCl or ouabain. Hyperpolarization, induced by valinomycin, increased membrane potential and L-arginine transport in PAEC and plasma membrane vesicles. Valinomycin also prevented the hypoxia-mediated decreases in membrane potential and L-arginine transport in PAEC. These results indicate that hypoxia-induced plasma membrane depolarization is responsible for reduced L-arginine transport by system y+ in hypoxic porcine PAEC.

Economic Growth: New Problems and New Risks

2006 ◽  
pp. 20-37 ◽  
Author(s):  
M. Ershov
Keyword(s):  
Economic Growth ◽  
Foreign Exchange ◽  
Driving Force ◽  
Structural Changes ◽  
Rate Of Growth

The economic growth, which is underway in Russia, raises new questions to be addressed. How to improve the quality of growth, increasing the role of new competitive sectors and transforming them into the driving force of growth? How can progressive structural changes be implemented without hampering the rate of growth in general? What are the main external and internal risks, which may undermine positive trends of development? The author looks upon financial, monetary and foreign exchange aspects of the problem and comes up with some suggestions on how to make growth more competitive and sustainable.

La politique forestière vaudoise: une orientation résolument «patrimoine multifonctionnel» | Forestry policy in the canton of Vaud: the “multifunctional heritage” option

2011 ◽  
Vol 162 (7) ◽  
pp. 209-215
Author(s):  
Jean-François Métraux
Keyword(s):  
Driving Force ◽  
Management Plan ◽  
The Political ◽  
Wood Production ◽  
Forest Owners ◽  
Forestry Policy ◽  
Forestry Management ◽  
Political Decisions ◽  
Forest Managers

In the years since 2000, the authorities in charge of forests in canton Vaud have made some substantial changes as a reaction to the political decisions arising from the Swiss Forest Programme and the projected revision of the Federal forestry Law, as well as to the deterioration of the economic situation in forestry enterprises. This article gives a survey of the directions taken. Thus the canton recognises the primordial role of wood production as a driving force behind the creation of a multifunctional forest. The Service for Forests, Wildlife and Nature has invested a great deal in planning, and has redefined the management plan to be an instrument intended for forest owners and forest managers. The canton has innovated by introducing forestry groups and a scheme of equalisation of forestry costs between communes. Hence the conception of forestry management in canton Vaud is resolutely that of a multifunctional natural heritage.

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