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Mohammad T Mazhab-Jafari, Alexis Rohou, Carla Schmidt, Stephanie A Bueler, Samir Benlekbir, Carol V Robinson, John L Rubinstein
Vacuolar-type ATPases (V-ATPases) are ATP-powered proton pumps involved in processes such as endocytosis, lysosomal degradation, secondary transport, TOR signalling, and osteoclast and kidney function. ATP hydrolysis in the soluble catalytic V1 region drives proton translocation through the membrane-embedded VO region via rotation of a rotor subcomplex. Variability in the structure of the intact enzyme has prevented construction of an atomic model for the membrane-embedded motor of any rotary ATPase. We induced dissociation and auto-inhibition of the V1 and VO regions of the V-ATPase by starving the yeast Saccharomyces cerevisiae, allowing us to obtain a ~3...
October 24, 2016: Nature
Jorge A Lobato-Álvarez, María L Roldán, Teresa Del Carmen López-Murillo, Ricardo González-Ramírez, José Bonilla-Delgado, Liora Shoshani
Na(+), K(+)-ATPase, or the Na(+) pump, is a key component in the maintenance of the epithelial phenotype. In most epithelia, the pump is located in the basolateral domain. Studies from our laboratory have shown that the β1 subunit of Na(+), K(+)-ATPase plays an important role in this mechanism because homotypic β1-β1 interactions between neighboring cells stabilize the pump in the lateral membrane. However, in the retinal pigment epithelium (RPE), the Na(+) pump is located in the apical domain. The mechanism of polarization in this epithelium is unclear...
2016: Frontiers in Physiology
Samir S Roy, Manju Kapoor
Hsp90 contains two distinct Nucleotide Binding Sites (NBS), in its N-terminal domain (NTD) and C-terminal domain (CTD), respectively. The NTD site belongs to the GHKL super-family of ATPases and has been the subject of extensive characterization. However, a structure of the nucleotide-bound form of CTD is still unavailable. In this study molecular modeling was employed to incorporate experimental data using partial constructs of the CTD, from work published by many research groups, onto existing structural models of its apo- form...
October 3, 2016: Journal of Molecular Graphics & Modelling
Wanting Zhao, Tammam Alama, Kosuke Kusamori, Hidemasa Katsumi, Toshiyasu Sakane, Akira Yamamoto
The purpose of this study was to investigate the effects of polyoxyethylene 10-oleyl ether and polyoxyethylene 9-lauryl ether, 2 polyoxyethylene alkyl ethers, on the transport and absorption of 2 P-glycoprotein (P-gp) substrates, quinidine and prednisolone, across the intestinal membrane and to elucidate the inhibitory mechanisms of intestinal P-gp by these polyoxyethylene alkyl ethers. For in vitro studies, we used a diffusion chamber method and the Caco-2 cell model. An in situ closed-loop method was used for in vivo study...
October 19, 2016: Journal of Pharmaceutical Sciences
Shigeto Sato, Masato Koike, Manabu Funayama, Junji Ezaki, Takahiro Fukuda, Takashi Ueno, Yasuo Uchiyama, Nobutaka Hattori
Kufor-Rakeb syndrome (KRS) is an autosomal recessive form of early-onset parkinsonism linked to the PARK9 locus. The causative gene for KRS is Atp13a2, which encodes a lysosomal type 5 P-type ATPase. We recently showed that KRS/PARK9-linked mutations lead to several lysosomal alterations, including reduced proteolytic processing of cathepsin D in vitro. However, it remains unknown how deficiency of Atp13a2 is connected to lysosomal impairments. To address this issue, we analyzed brain tissues of Atp13a2 conditional-knockout mice, which exhibited characteristic features of neuronal ceroid lipofuscinosis, including accumulation of lipofuscin positive for subunit c of mitochondrial ATP synthase, suggesting that a common pathogenic mechanism underlies both neuronal ceroid lipofuscinosis and Parkinson disease...
October 19, 2016: American Journal of Pathology
Lana Shabala, Jingyi Zhang, Igor I Pottosin, Jayakumar Bose, Min Zhu, Anja Thoe Fuglsang, Ana Velarde-Buendia, Amandine Massart, Camilla B Hill, Ute Roessner, Antony Bacic, Honghong Wu, Elisa Azzarello, Camilla Pandolfi, Meixue Zhou, Charlotte Poschenrieder, Stefano Mancuso, Sergey Shabala
While the importance of cell-type specificity in plant adaptive responses is widely accepted, only a limited number of studies have addressed this issue at the functional level. We have combined electrophysiological, imaging, and biochemical techniques to reveal physiological mechanisms conferring higher sensitivity of apical root cells to salinity in barley. We show that salinity application to the root apex arrests root growth in a highly tissue- and treatment-specific manner. Although salinity-induced transient net Na+ uptake was about 4-fold higher in the root apex compared with the mature zone, mature root cells accumulated more cytosolic and vacuolar Na+ suggesting that higher sensitivity of apical cells to salt is not related to either enhanced Na+ exclusion or sequestration inside the root...
October 21, 2016: Plant Physiology
Jamie L Burgess, R Alan Burgess, Yalemi Morales, Jenna M Bouvang, Sean J Johnson, Nicholas E Dickenson
Like many Gram-negative pathogens, Shigella rely on a complex type three secretion system (T3SS) to inject effector proteins into host cells, take over host functions, and ultimately establish infection. Despite these critical roles, the energetics and regulatory mechanisms controlling the T3SS and pathogen virulence remain largely unclear. In this study, we present a series of high-resolution crystal structures of Spa47 and use the structures to model an activated Spa47 oligomer, finding that ATP hydrolysis may be supported by specific sidechain contributions from adjacent protomers within the complex...
October 21, 2016: Journal of Biological Chemistry
Masaya Takumida, Hiroshi Takumida, Matti Anniko
CONCLUSION: Gastric type H(+),K(+)-ATPase in the vestibular end organs may be of importance for K(+) circulation and may also be related to pH regulation in vestibular end organs and endolymphatic sac. OBJECTIVE: To analyze the expression of gastric-type H(+),K(+)-ATPase in normal mouse vestibular end organs. METHODS: 8 weeks old CBA/J mice were used in this study. The presence of gastric-type H(+),K(+)-ATPase α and β in the vestibular end organs, viz...
October 21, 2016: Acta Oto-laryngologica
Beibei Wang, Joshua Francis, Monika Sharma, Sean M Law, Alexander V Predeus, Michael Feig
Allostery is conformation regulation by propagating a signal from one site to another distal site. This study focuses on the long-range communication in DNA mismatch repair proteins MutS and its homologs where intramolecular signaling has to travel over 70 Å to couple lesion detection to ATPase activity and eventual downstream repair. Using dynamic network analysis based on extensive molecular dynamics simulations, multiple preserved communication pathways were identified that would allow such long-range signaling...
October 2016: PLoS Computational Biology
Xiaoli Xu, Yue Wu, Mingyang Hu, Xiang Li, Qichao Bao, Jinlei Bian, Qidong You, Xiaojin Zhang
DDO-6101, a simplified structure obtained from the Garcinia natural product (NP) gambogic acid (GA), has been previously shown to possess high cytotoxicity to a variety of human tumour cell lines. To improve its physicochemical properties and in vivo cytotoxic potency, a series of novel carbamate-bearing derivatives based on DDO-6101 was synthesized and characterized. The structural modifications revealed that the presence of a carbamate moiety was useful for obtaining comparable cytotoxicity and improved aqueous solubility and permeability...
October 21, 2016: Scientific Reports
Alexander N Shikov, Olga N Pozharitskaya, Valery G Makarov
PURPOSE: Aralia elata var. mandshurica (Rupr. & Maxim.) J.Wen syn. A. mandshurica Rupr. & Maxim is evaluated for its medicinal application. The aim of this study is to analyze pharmacological studies on A. elata var. mandshurica published until December 2015. METHODS: The information regarding the chemistry, safety, effectiveness, and pharmacological and clinical effects of A. elata was systematically collected from the scientific literature through library catalogs; online services such as E-library...
November 15, 2016: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Melanie Ott, Débora Marques, Christina Funk, Susanne M Bailer
BACKGROUND: Herpes simplex virus type 1 (HSV1), a member of the alphaherpesvirinae, can cause recurrent facial lesions and encephalitis. Two membrane envelopment processes, one at the inner nuclear membrane and a second at cytoplasmic membranes are crucial for a productive viral infection. Depending on the subfamily, herpesviruses encode more than 11 different transmembrane proteins including members of the tail-anchored protein family. HSV1 encodes three tail-anchored proteins pUL34, pUL56 and pUS9 characterized by a single hydrophobic region positioned at their C-terminal end that needs to be released from the ribosome prior to posttranslational membrane insertion...
October 20, 2016: Virology Journal
Yuan-Bo Wu, Li Zhang, Wen-Ting Li, Yi Yang, Jiang-Ming Zhao
BACKGROUND: Artesunate (ART) is an antimalarial drug with potential anti-inflammatory effect. This study aimed to explore the potential protective role of ART in hepatic encephalopathy (HE), involving its function against ammonia toxicity. METHODS: HE rats were induced by the administration of thioacetamide (TAA, 300mg/kg/day). Spatial learning ability was tested in both Morris water and eight-arm radial maze. Rat cerebellar granule neurons (CGNs) were prepared for ammonia treatment in vitro, in line with SH-SY5Y and C6 cells...
October 17, 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Lixia Xiang, Lipan Hu, Weinan Xu, Ai Zhen, Liang Zhang, Xiaohui Hu
Gamma-aminobutyric acid (GABA) is important in plant responses to environmental stresses. We wished to clarify the role of GABA in maintenance of photosynthesis in muskmelon seedlings (Cucumis melo L., cv. Yipintianxia) during saline-alkaline stress. To this end, we assessed the effect of GABA on the structure and function of the photosynthetic apparatus in muskmelon seedlings grown under saline-alkaline stress. These stresses in combination reduced net photosynthetic rate, gas-exchange, and inhibited photosystem II (PSII) electron transport as measured by the JIP-test...
2016: PloS One
Anup Arumughan, Yvette Roske, Carolin Barth, Laura Lleras Forero, Kenny Bravo-Rodriguez, Alexandra Redel, Simona Kostova, Erik McShane, Robert Opitz, Katja Faelber, Kirstin Rau, Thorsten Mielke, Oliver Daumke, Matthias Selbach, Elsa Sanchez-Garcia, Oliver Rocks, Daniela Panáková, Udo Heinemann, Erich E Wanker
Interaction mapping is a powerful strategy to elucidate the biological function of protein assemblies and their regulators. Here, we report the generation of a quantitative interaction network, directly linking 14 human proteins to the AAA+ ATPase p97, an essential hexameric protein with multiple cellular functions. We show that the high-affinity interacting protein ASPL efficiently promotes p97 hexamer disassembly, resulting in the formation of stable p97:ASPL heterotetramers. High-resolution structural and biochemical studies indicate that an extended UBX domain (eUBX) in ASPL is critical for p97 hexamer disassembly and facilitates the assembly of p97:ASPL heterotetramers...
October 20, 2016: Nature Communications
Haifang Zhang, Yunxia Zhu, Xiaofang Xie, Min Wang, Hong Du, Shungao Xu, Ying Zhang, Mingyu Gong, Bin Ni, Huaxi Xu, Xinxiang Huang
The linear plasmid pBSSB1 mediates the flagellar phase variation in H:z66 positive Salmonella enterica serovar Typhi (S. Typhi). The gene named stp17 (S. Typhi plasmid number 17 gene) is located on pBSSB1 and encodes the protein STP17. The expression pattern at the protein-level and function of STP17 remains unknown. In this study, the recombinant protein STP17His6 was expressed, purified and used to prepare the polyclonal anti-STP17 antibody. We detected protein-level expression of stp17 in S. Typhi and further investigated the protein expression characteristics of stp17 in different growth phases by western blot analysis...
2016: Frontiers in Cellular and Infection Microbiology
Azam Moshtaghi, Md Lifat Rahi, Viet Tuan Nguyen, Peter B Mather, David A Hurwood
BACKGROUND: Understanding the genomic basis of osmoregulation (candidate genes and/or molecular mechanisms controlling the phenotype) addresses one of the fundamental questions in evolutionary ecology. Species distributions and adaptive radiations are thought to be controlled by environmental salinity levels, and efficient osmoregulatory (ionic balance) ability is the main mechanism to overcome the problems related to environmental salinity gradients. METHODS: To better understand how osmoregulatory performance in freshwater (FW) crustaceans allow individuals to acclimate and adapt to raised salinity conditions, here we (i), reviewed the literature on genes that have been identified to be associated with osmoregulation in FW crustaceans, and (ii), performed a transcriptomic analysis using cDNA libraries developed from mRNA isolated from three important osmoregulatory tissues (gill, antennal gland, hepatopancreas) and total mRNA from post larvae taken from the freshwater prawn, Macrobrachium australiense using Illumina deep sequencing technology...
2016: PeerJ
Jianbo Li, Huixia Jia, Xiaojiao Han, Jin Zhang, Pei Sun, Mengzhu Lu, Jianjun Hu
Salix psammophila is a desert shrub willow that has extraordinary adaptation to abiotic stresses and plays an important role in maintaining local ecosystems. Moreover, S. psammophila is regarded as a promising biomass feedstock because of its high biomass yields and short rotation coppice cycle. However, few suitable reference genes (RGs) for quantitative real-time polymerase chain reaction (qRT-PCR) constrain the study on normalization of gene expression in S. psammophila until now. Here, we investigated the expression stabilities of 14 candidate RGs across tissue types and under four abiotic stress treatments, including heat, cold, salt, and drought treatments...
2016: Frontiers in Plant Science
Sarah A Overall, Dorothée Bourges, Ian R van Driel, Paul A Gleeson
How the immune system maintains peripheral tolerance under inflammatory conditions is poorly understood. Here we assessed the fate of gastritogenic T cells following inflammatory activation in vivo. Self-reactive T cells (A23 T cells) specific for the gastric H(+) /K(+) ATPase α subunit (HKα) were transferred into immunosufficient recipient mice and immunised at a site distant to the stomach with adjuvant containing the cognate HKα peptide antigen. Activation of A23 T cells by immunisation did not impact on either immune tolerance or protection from gastric autoimmunity in wild-type BALB/c mice...
October 19, 2016: European Journal of Immunology
Andrea J Morash, Sara R C Mackellar, Louise Tunnah, David A Barnett, Kilian M Stehfest, Jayson M Semmens, Suzanne Currie
Estuarine habitats are frequently used as nurseries by elasmobranch species for their protection and abundant resources; however, global climate change is increasing the frequency and severity of environmental challenges in these estuaries that may negatively affect elasmobranch physiology. Hyposmotic events are particularly challenging for marine sharks that osmoconform, and species-specific tolerances are not well known. Therefore, we sought to determine the effects of an acute (48 h) ecologically relevant hyposmotic event (25...
2016: Conservation Physiology
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