Oscillatory Activity of P-Type Membrane Adenosine Triphosphatases: a Kinetic Model

2005 ◽  
Vol 70 (4) ◽  
pp. 440-444 ◽  
Author(s):  
B. N. Goldstein ◽  
A. A. Mayevsky ◽  
D. T. Zakrjevskaya
Keyword(s):  
Kinetic Model ◽  
Oscillatory Activity ◽  
Adenosine Triphosphatases ◽  
P Type

Kinetic model for dynein oscillatory activity

2008 ◽  
Vol 134 (1-2) ◽  
pp. 20-24 ◽  
Author(s):  
B.N. Goldstein ◽  
A.M. Aksirov ◽  
D.T. Zakrjevskaya
Keyword(s):  
Kinetic Model ◽  
Oscillatory Activity

A simple kinetic model for dynein oscillatory activity

2008 ◽  
Vol 42 (1) ◽  
pp. 123-126 ◽  
Author(s):  
B. N. Goldstein ◽  
A. M. Aksirov ◽  
D. T. Zakrjevskaya
Keyword(s):  
Kinetic Model ◽  
Oscillatory Activity ◽  
Simple Kinetic Model

scholarly journals A malaria parasite phospholipid flippase safeguards midgut traversal of ookinetes for mosquito transmission

2021 ◽  
Vol 7 (30) ◽  
pp. eabf6015
Author(s):  
Zhenke Yang ◽  
Yang Shi ◽  
Huiting Cui ◽  
Shuzhen Yang ◽  
Han Gao ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lipid Bilayers ◽  
Malaria Parasite ◽  
Membrane Lipid ◽  
Plasmodium Yoelii ◽  
Midgut Epithelium ◽  
Rodent Malaria Parasite ◽  
Adenosine Triphosphatases ◽  
Parasite Survival ◽  
P Type

Mosquito midgut epithelium traversal is essential for malaria parasite transmission. Phospholipid flippases are eukaryotic type 4 P-type adenosine triphosphatases (P4-ATPases), which, in association with CDC50, translocate phospholipids across the membrane lipid bilayers. In this study, we investigated the function of a putative P4-ATPase, ATP7, from the rodent malaria parasite Plasmodium yoelii. Disruption of ATP7 blocks the parasite infection of mosquitoes. ATP7 is localized on the ookinete plasma membrane. While ATP7-depleted ookinetes are capable of invading the midgut, they are eliminated within the epithelial cells by a process independent from the mosquito complement-like immunity. ATP7 colocalizes and interacts with the flippase cofactor CDC50C. Depletion of CDC50C phenocopies ATP7 deficiency. ATP7-depleted ookinetes fail to uptake phosphatidylcholine across the plasma membrane. Ookinete microinjection into the mosquito hemocoel reverses the ATP7 deficiency phenotype. Our study identifies Plasmodium flippase as a mechanism of parasite survival in the midgut epithelium that is required for mosquito transmission.

scholarly journals Cryo-EM structures capture the transport cycle of the P4-ATPase flippase

Science ◽  
2019 ◽  
Vol 365 (6458) ◽  
pp. 1149-1155 ◽  
Author(s):  
Masahiro Hiraizumi ◽  
Keitaro Yamashita ◽  
Tomohiro Nishizawa ◽  
Osamu Nureki
Keyword(s):  
Membrane Trafficking ◽  
Acyl Chain ◽  
Phosphorylation Site ◽  
Head Group ◽  
Transmembrane Helices ◽  
Type Iv ◽  
Adenosine Triphosphatases ◽  
Lipid Environment ◽  
P Type ◽  
Phosphorylation Domain

In eukaryotic membranes, type IV P-type adenosine triphosphatases (P4-ATPases) mediate the translocation of phospholipids from the outer to the inner leaflet and maintain lipid asymmetry, which is critical for membrane trafficking and signaling pathways. Here, we report the cryo–electron microscopy structures of six distinct intermediates of the human ATP8A1-CDC50a heterocomplex at resolutions of 2.6 to 3.3 angstroms, elucidating the lipid translocation cycle of this P4-ATPase. ATP-dependent phosphorylation induces a large rotational movement of the actuator domain around the phosphorylation site in the phosphorylation domain, accompanied by lateral shifts of the first and second transmembrane helices, thereby allowing phosphatidylserine binding. The phospholipid head group passes through the hydrophilic cleft, while the acyl chain is exposed toward the lipid environment. These findings advance our understanding of the flippase mechanism and the disease-associated mutants of P4-ATPases.

Interface morphology of thermal oxide grown on polycrystalline silicon by different processes

1992 ◽  
Vol 50 (2) ◽  
pp. 1396-1397
Author(s):  
H. Yen ◽  
E. P. Kvam ◽  
R. Bashir ◽  
S. Venkatesan ◽  
G. W. Neudeck
Keyword(s):  
Integrated Circuits ◽  
Polycrystalline Silicon ◽  
Silicon Films ◽  
Interface Morphology ◽  
Oxide Interface ◽  
Poly Silicon ◽  
Thermal Oxide ◽  
Grain Orientations ◽  
Polycrystalline Silicon Films ◽  
P Type

Polycrystalline silicon, when highly doped, is commonly used in microelectronics applications such as gates and interconnects. The packing density of integrated circuits can be enhanced by fabricating multilevel polycrystalline silicon films separated by insulating SiO2 layers. It has been found that device performance and electrical properties are strongly affected by the interface morphology between polycrystalline silicon and SiO2. As a thermal oxide layer is grown, the poly silicon is consumed, and there is a volume expansion of the oxide relative to the atomic silicon. Roughness at the poly silicon/thermal oxide interface can be severely deleterious due to stresses induced by the volume change during oxidation. Further, grain orientations and grain boundaries may alter oxidation kinetics, which will also affect roughness, and thus stress.Three groups of polycrystalline silicon films were deposited by LPCVD after growing thermal oxide on p-type wafers. The films were doped with phosphorus or arsenic by three different methods.

Determination of arsenic atom distribution arsenic doped silicon using HOLZ-line analysis

1996 ◽  
Vol 54 ◽  
pp. 976-977
Author(s):  
Y. Kikuchi ◽  
N. Hashikawa ◽  
F. Uesugi ◽  
E. Wakai ◽  
K. Watanabe ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Zone Axis ◽  
Experimental Result ◽  
Background Intensity ◽  
Crystal Thickness ◽  
Arsenic Atom ◽  
Doped Silicon ◽  
P Type ◽  
Line Analysis

In order to measure the concentration of arsenic atoms in nanometer regions of arsenic doped silicon, the HOLZ analysis is carried out underthe exact [011] zone axis observation. In previous papers, it is revealed that the position of two bright lines in the outer SOLZ structures on the[011] zone axis is little influenced by the crystal thickness and the background intensity caused by inelastic scattering electrons, but is sensitive to the concentration of As atoms substitutbnal for Siatomic site.As the result, it becomes possible to determine the concentration of electrically activated As atoms in silicon within an observed area by means of the simple fitting between experimental result and dynamical simulatioan. In the present work, in order to investigate the distribution of electrically activated As in silicon, the outer HOLZ analysis is applied using a nanometer sized probe of TEM equipped with a FEG.Czodiralsld-gown<100>orientated p-type Si wafers with a resistivity of 10 Ώ cm are used for the experiments.TheAs+ implantation is performed at a dose of 5.0X1015cm-2at 25keV.

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