scholarly journals Protection against Mitochondrial and Metal Toxicity Depends on Functional Lipid Binding Sites in ATP13A2

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Shaun Martin ◽  
Sarah van Veen ◽  
Tine Holemans ◽  
Seyma Demirsoy ◽  
Chris van den Haute ◽  
...  
Keyword(s):  
Binding Sites ◽  
Lipid Binding ◽  
Stress Conditions ◽  
Activation Mechanism ◽  
Mitochondrial Stress ◽  
Cellular Protection ◽  
Shsy5y Cell ◽  
Related Stress ◽  
P Type

The late endo-/lysosomal P-type ATPase ATP13A2 (PARK9) is implicated in Parkinson’s disease (PD) and Kufor-Rakeb syndrome, early-onset atypical Parkinsonism. ATP13A2 interacts at the N-terminus with the signaling lipids phosphatidic acid (PA) and phosphatidylinositol (3,5) bisphosphate (PI(3,5)P2), which modulate ATP13A2 activity under cellular stress conditions. Here, we analyzed stable human SHSY5Y cell lines overexpressing wild-type (WT) or ATP13A2 mutants in which three N-terminal lipid binding sites (LBS1–3) were mutated. We explored the regulatory role of LBS1–3 in the cellular protection by ATP13A2 against mitochondrial stress induced by rotenone and found that the LBS2-3 mutants displayed an abrogated protective effect. Moreover, in contrast to WT, the LBS2 and LBS3 mutants responded poorly to pharmacological inhibition of, respectively, PI(3,5)P2 and PA formation. We further demonstrate that PA and PI(3,5)P2 are also required for the ATP13A2-mediated protection against the toxic metals Mn2+, Zn2+, and Fe3+, suggesting a general lipid-dependent activation mechanism of ATP13A2 in various PD-related stress conditions. Our results indicate that the ATP13A2-mediated protection requires binding of PI(3,5)P2 to LBS2 and PA to LBS3. Thus, targeting the N-terminal lipid binding sites of ATP13A2 might offer a therapeutic approach to reduce cellular toxicity of various PD insults including mitochondrial stress.

O-linked glycosylation of von Willebrand factor modulates the interaction with platelet receptor glycoprotein Ib under static and shear stress conditions

Blood ◽  
2012 ◽  
Vol 120 (1) ◽  
pp. 214-222 ◽  
Author(s):  
Agata A. Nowak ◽  
Kevin Canis ◽  
Anne Riddell ◽  
Michael A. Laffan ◽  
Thomas A. J. McKinnon
Keyword(s):  
Shear Stress ◽  
Binding Sites ◽  
Stress Conditions ◽  
Collagen Binding ◽  
Platelet Receptor ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Double Cluster

AbstractWe have examined the effect of the O-linked glycan (OLG) structures of VWF on its interaction with the platelet receptor glycoprotein Ibα. The 10 OLGs were mutated individually and as clusters (Clus) on either and both sides of the A1 domain: Clus1 (N-terminal side), Clus2 (C-terminal side), and double cluster (DC), in both full-length-VWF and in a VWF construct spanning D′ to A3 domains. Mutations did not alter VWF secretion by HEK293T cells, multimeric structure, or static collagen binding. The T1255A, Clus1, and DC variants caused increased ristocetin-mediated GPIbα binding to VWF. Platelet translocation rate on OLG mutants was increased because of reduced numbers of GPIbα binding sites but without effect on bond lifetime. In contrast, OLG mutants mediated increased platelet capture on collagen under high shear stress that was associated with increased adhesion of these variants to the collagen under flow. These findings suggest that removal of OLGs increases the flexibility of the hinge linker region between the D3 and A1 domain, facilitating VWF unfolding by shear stress, thereby enhancing its ability to bind collagen and capture platelets. These data demonstrate an important functional role of VWF OLGs under shear stress conditions.

scholarly journals A lipid switch unlocks Parkinson’s disease-associated ATP13A2

2015 ◽  
Vol 112 (29) ◽  
pp. 9040-9045 ◽  
Author(s):  
Tine Holemans ◽  
Danny Mollerup Sørensen ◽  
Sarah van Veen ◽  
Shaun Martin ◽  
Diane Hermans ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Therapeutic Strategy ◽  
Membrane Surface ◽  
Model Systems ◽  
Molecular Function ◽  
Mitochondrial Stress ◽  
Cellular Protection ◽  
Catalytically Active ◽  
P Type

ATP13A2 is a lysosomal P-type transport ATPase that has been implicated in Kufor–Rakeb syndrome and Parkinson’s disease (PD), providing protection against α-synuclein, Mn2+, and Zn2+ toxicity in various model systems. So far, the molecular function and regulation of ATP13A2 remains undetermined. Here, we demonstrate that ATP13A2 contains a unique N-terminal hydrophobic extension that lies on the cytosolic membrane surface of the lysosome, where it interacts with the lysosomal signaling lipids phosphatidic acid (PA) and phosphatidylinositol(3,5)bisphosphate [PI(3,5)P2]. We further demonstrate that ATP13A2 accumulates in an inactive autophosphorylated state and that PA and PI(3,5)P2 stimulate the autophosphorylation of ATP13A2. In a cellular model of PD, only catalytically active ATP13A2 offers cellular protection against rotenone-induced mitochondrial stress, which relies on the availability of PA and PI(3,5)P2. Thus, the N-terminal binding of PA and PI(3,5)P2 emerges as a key to unlock the activity of ATP13A2, which may offer a therapeutic strategy to activate ATP13A2 and thereby reduce α-synuclein toxicity or mitochondrial stress in PD or related disorders.

scholarly journals Role of Proton Motive Force in Photoinduction of Cytoplasmic Streaming in Vallisneria Mesophyll Cells

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 376
Author(s):  
Akiko Harada ◽  
Yoshiji Okazaki ◽  
Toshinori Kinoshita ◽  
Reiko Nagai ◽  
Shingo Takagi
Keyword(s):  
Cytoplasmic Streaming ◽  
Red Light ◽  
Proton Motive Force ◽  
Motive Force ◽  
Activation Mechanism ◽  
Dependent Manner ◽  
Mesophyll Cells ◽  
P Type ◽  
Exchange Activity

In mesophyll cells of the aquatic monocot Vallisneria, red light induces rotational cytoplasmic streaming, which is regulated by the cytoplasmic concentration of Ca2+. Our previous investigations revealed that red light induces Ca2+ efflux across the plasma membrane (PM), and that both the red light-induced cytoplasmic streaming and the Ca2+ efflux are sensitive to vanadate, an inhibitor of P-type ATPases. In this study, pharmacological experiments suggested the involvement of PM H+-ATPase, one of the P-type ATPases, in the photoinduction of cytoplasmic streaming. We hypothesized that red light would activate PM H+-ATPase to generate a large H+ motive force (PMF) in a photosynthesis-dependent manner. We demonstrated that indeed, photosynthesis increased the PMF and induced phosphorylation of the penultimate residue, threonine, of PM H+-ATPase, which is a major activation mechanism of H+-ATPase. The results suggested that a large PMF generated by PM H+-ATPase energizes the Ca2+ efflux across the PM. As expected, we detected a putative Ca2+/H+ exchange activity in PM vesicles isolated from Vallisneria leaves.

scholarly journals Further studies on the role of phospholipids in determining the characteristics of mitochondrial binding sites for type I hexokinase.

2000 ◽  
Vol 47 (4) ◽  
pp. 1045-1060 ◽  
Author(s):  
J Hutny ◽  
J E Wilson
Keyword(s):  
Binding Sites ◽  
Type A ◽  
Brain Mitochondria ◽  
Bovine Brain ◽  
Type I ◽  
Type B ◽  
Acidic Phospholipids ◽  
P Type ◽  
Triton X

Previous work has indicated that two types (A and B) of binding sites for hexokinase exist, but in different proportions, on brain mitochondria from various species. Hexokinase is readily solubilized from Type A sites by glucose 6-phosphate (Glc-6-P), while hexokinase bound to Type B sites remains bound even in the presence of Glc-6-P. Type A:Type B ratios are approximately 90:10, 60:40, 40:60, and 20:80 for brain mitochondria from rat, rabbit, bovine and human brain, respectively. The present study has indicated that MgCl2-dependent partitioning of mitochondrially bound hexokinase into a hydrophobic (Triton X-114) phase is generally correlated with the proportion of Type B sites. This partitioning behavior is sensitive to phospholipase C, implying that the factor(s) responsible for conferring hydrophobic character is(are) phospholipid(s). Substantial differences were also seen in the resistance of hexokinase, bound to brain mitochondria from various species, to solubilization by Triton X-100, Triton X-114, or digitonin. This resistance increased with proportion of Type B sites. Enrichment of bovine brain mitochondria in acidic phospholipids (phosphatidylserine or phosphatidylinositol), but not phosphatidylcholine or phosphatidylethanolamine, substantially increased solubilization of the enzyme after incubation at 37 degrees C. Collectively, the results imply that the Type A and Type B sites are located in membrane domains of different lipid composition, the Type A sites being in domains enriched in acidic phospholipids which lead to greater susceptibility to solubilisation by Glc-6-P.

scholarly journals Modulation of the potassium channel KcsA by anionic phospholipids: Role of arginines at the non-annular lipid binding sites

2019 ◽  
Vol 1861 (10) ◽  
pp. 183029 ◽  
Author(s):  
José A. Poveda ◽  
A. Marcela Giudici ◽  
M. Lourdes Renart ◽  
Oscar Millet ◽  
Andrés Morales ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Binding Sites ◽  
Lipid Binding ◽  
Anionic Phospholipids ◽  
Potassium Channel Kcsa

1758-P: Type 2 Diabetes–Associated Mood Disorders: Role of Insulin Resistance in Serotonergic Neurons

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1758-P
Author(s):  
HUGO MARTIN ◽  
SÉBASTIEN BULLICH ◽  
FABIEN DUCROCQ ◽  
MARION GRALAND ◽  
CLARA OLIVRY ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Mood Disorders ◽  
Serotonergic Neurons ◽  
P Type

STRUCTURAL COMPONENTS OF THE PRIVATE MEDICAL SECTOR ACTIVATION MECHANISM

Economical ◽  
2019 ◽  
Vol 2 (2(21)) ◽  
pp. 170-177
Author(s):  
Anzhela Bairak ◽  
Keyword(s):  
Health Care ◽  
Health Care System ◽  
Activation Mechanism ◽  
Practical Significance ◽  
Structural Components ◽  
Medical Sector ◽  
Analysis And Synthesis ◽  
Private Medicine ◽  
Care System

The article examines the problems of private medicine in the health care system of the country. The aim of the article is to determine the structural components of the mechanism of activation of the private medical sector as a reserve for the provision of quality and affordable medical services and a driver for the development of the medical industry. The descriptive-analytical method, methods of analysis and synthesis, comparison, statistical, analysis and scientific generalization were used in the paper. The study substantiates the strengthening of the role of the private medical sector in the health care management system. The key problems of the domestic private medical sector and the restraining factors of its development are identified. It is concluded that it is necessary to develop a mechanism to promote the development of private medicine through a policy of active change in the health care system. The directions of activation of the private medical sector as a target reference point in the process of determining the structural elements of the organizational and economic mechanism are outlined. The structural detail of the mechanism of activation of the private medical sector for optimization of the health care system is offered. The practical significance of the obtained results is that the results of the research presented in the article are a practical basis for the development and improvement of mechanisms of public administration in the field of health care.

scholarly journals The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa

2021 ◽  
Vol 22 (8) ◽  
pp. 3982
Author(s):  
Karolina Kotecka ◽  
Adam Kawalek ◽  
Kamil Kobylecki ◽  
Aneta Agnieszka Bartosik
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Transcriptional Profiling ◽  
Mrna Level ◽  
Transcriptional Regulators ◽  
Resistance Mechanisms ◽  
Chronic Infections ◽  
Environmental Signals ◽  
Regulatory Systems

Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459–PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459–PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.

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