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https://www.readbyqxmd.com/read/28646497/geometrical-principles-of-homomeric-%C3%AE-barrels-and-%C3%AE-helices-application-to-modelling-amyloid-protofilaments
#1
Steven Hayward, E James Milner-White
Examples of homomeric β-helices and β-barrels have recently emerged. Here we generalise the theory for the shear number in β-barrels to encompass β-helices and homomeric structures. We introduce the concept of the "β-strip", the set of parallel or antiparallel neighbouring strands, from which the whole helix can be generated giving it n-fold rotational symmetry. In this context the shear number is interpreted as the sum around the helix of the fixed register shift between neighbouring identical β-strips...
June 24, 2017: Proteins
https://www.readbyqxmd.com/read/28646414/dynamic-meso-scale-anchorage-of-gpi-anchored-receptors-in-the-plasma-membrane-prion-protein-vs-thy1
#2
Yuri L Nemoto, Roger J Morris, Hiroko Hijikata, Taka A Tsunoyama, Akihiro C E Shibata, Rinshi S Kasai, Akihiro Kusumi, Takahiro K Fujiwara
The central mechanism for the transmission of the prion protein misfolding is the structural conversion of the normal cellular prion protein to the pathogenic misfolded prion protein, by the interaction with misfolded prion protein. This process might be enhanced due to the homo-dimerization/oligomerization of normal prion protein. However, the behaviors of normal prion protein in the plasma membrane have remained largely unknown. Here, using single fluorescent-molecule imaging, we found that both prion protein and Thy1, a control glycosylphosphatidylinositol-anchored protein, exhibited very similar intermittent transient immobilizations lasting for a few seconds within an area of 24...
June 24, 2017: Cell Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28644435/p53-amyloid-formation-leading-to-its-loss-of-function-implications-in-cancer-pathogenesis
#3
Saikat Ghosh, Shimul Salot, Shinjinee Sengupta, Ambuja Navalkar, Dhiman Ghosh, Reeba Jacob, Subhadeep Das, Rakesh Kumar, Narendra Nath Jha, Shruti Sahay, Surabhi Mehra, Ganesh M Mohite, Santanu K Ghosh, Mamata Kombrabail, Guruswamy Krishnamoorthy, Pradip Chaudhari, Samir K Maji
The transcriptional regulator p53 has an essential role in tumor suppression. Almost 50% of human cancers are associated with the loss of p53 functions, where p53 often accumulates in the nucleus as well as in cytoplasm. Although it has been previously suggested that amyloid formation could be a cause of p53 loss-of-function in subset of tumors, the characterization of these amyloids and its structure-function relationship is not yet established. In the current study, we provide several evidences for the presence of p53 amyloid formation (in human and animal cancer tissues); along with its isolation from human cancer tissues and the biophysical characterization of these tissue-derived fibrils...
June 23, 2017: Cell Death and Differentiation
https://www.readbyqxmd.com/read/28636656/selective-propagation-of-mouse-passaged-scrapie-prions-with-long-incubation-period-from-a-mixed-prion-population-using-gt1-7-cells
#4
Kohtaro Miyazawa, Kentaro Masujin, Hiroyuki Okada, Yuko Ushiki-Kaku, Yuichi Matsuura, Takashi Yokoyama
In our previous study, we demonstrated the propagation of mouse-passaged scrapie isolates with long incubation periods (L-type) derived from natural Japanese sheep scrapie cases in murine hypothalamic GT1-7 cells, along with disease-associated prion protein (PrPSc) accumulation. We here analyzed the susceptibility of GT1-7 cells to scrapie prions by exposure to infected mouse brains at different passages, following interspecies transmission. Wild-type mice challenged with a natural sheep scrapie case (Kanagawa) exhibited heterogeneity of transmitted scrapie prions in early passages, and this mixed population converged upon one with a short incubation period (S-type) following subsequent passages...
2017: PloS One
https://www.readbyqxmd.com/read/28630454/treatment-with-a-non-toxic-self-replicating-anti-prion-delays-or-prevents-prion-disease-in-vivo
#5
R Diaz-Espinoza, R Morales, L Concha-Marambio, I Moreno-Gonzalez, F Moda, C Soto
Transmissible spongiform encephalopathies (TSEs) are fatal neurological disorders caused by prions, which are composed of a misfolded protein (PrP(Sc)) that self-propagates in the brain of infected individuals by converting the normal prion protein (PrP(C)) into the pathological isoform. Here, we report a novel experimental strategy for preventing prion disease based on producing a self-replicating, but innocuous PrP(Sc)-like form, termed anti-prion, which can compete with the replication of pathogenic prions...
June 20, 2017: Molecular Psychiatry
https://www.readbyqxmd.com/read/28630311/a-prokaryotic-viral-sequence-is-expressed-and-conserved-in-mammalian-brain
#6
Yang-Hui Yeh, Vignesh Gunasekharan, Laura Manuelidis
A natural and permanent transfer of prokaryotic viral sequences to mammals has not been reported by others. Circular "SPHINX" DNAs <5 kb were previously isolated from nuclease-protected cytoplasmic particles in rodent neuronal cell lines and brain. Two of these DNAs were sequenced after Φ29 polymerase amplification, and they revealed significant but imperfect homology to segments of commensal Acinetobacter phage viruses. These findings were surprising because the brain is isolated from environmental microorganisms...
June 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28630281/evidence-of-a-prion-like-transmission-of-p53-amyloid-in-saccharomyces-cerevisiae
#7
Shinjinee Sengupta, Samir K Maji, Santanu K Ghosh
Loss of p53 function is largely responsible for the occurrence of cancer in human. Aggregation of mutant p53 has been found in multiple cancer cell types suggesting a role of aggregation for loss of p53 function and cancer development. The p53 protein has recently been hypothesized to possess a prion-like conformation although experimental evidence is lacking. Here, we report that human p53 can be inactivated upon exposure to preformed fibrils containing an aggregation prone sequence specific peptide PILTIITL derived from p53 and the inactive state was found to be stable for many generations...
June 19, 2017: Molecular and Cellular Biology
https://www.readbyqxmd.com/read/28630146/er-stress-causes-widespread-protein-aggregation-and-prion-formation
#8
Norfadilah Hamdan, Paraskevi Kritsiligkou, Chris M Grant
Disturbances in endoplasmic reticulum (ER) homeostasis create a condition termed ER stress. This activates the unfolded protein response (UPR), which alters the expression of many genes involved in ER quality control. We show here that ER stress causes the aggregation of proteins, most of which are not ER or secretory pathway proteins. Proteomic analysis of the aggregated proteins revealed enrichment for intrinsically aggregation-prone proteins rather than proteins which are affected in a stress-specific manner...
June 19, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28623368/regulation-of-sub-compartmental-targeting-and-folding-properties-of-the-prion-like-protein-shadoo
#9
Anna Pepe, Rosario Avolio, Danilo Swann Matassa, Franca Esposito, Lucio Nitsch, Chiara Zurzolo, Simona Paladino, Daniela Sarnataro
Shadoo (Sho), a member of prion protein family, has been shown to prevent embryonic lethality in Prnp (0/0) mice and to be reduced in the brains of rodents with terminal prion diseases. Sho can also affect PrP structural dynamics and can increase the prion conversion into its misfolded isoform (PrP(Sc)), which is amyloidogenic and strictly related to expression, intracellular localization and association of PrP(C) to lipid rafts. We reasoned that if Sho possesses a natural tendency to convert to amyloid-like forms in vitro, it should be able to exhibit "prion-like" properties, such as PK-resistance and aggregation state, also in live cells...
June 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28621416/all-in-one-integrating-cell-polarity-meiosis-mitosis-and-mechanical-forces-in-early-oocyte-differentiation-in-vertebrates
#10
Yaniv M Elkouby
While the differentiation of oocytes is key for embryonic development, and its investigation is crucial for advancing our understanding of human reproduction and fertility, many fundamental questions in oogenesis have been long standing. However, recent technical advances have led to several breakthroughs mainly in mice and zebrafish. Here I review these recent findings, including regulation and organization of the germline cyst, the mechanistics of chromosomal pairing, establishment of cell polarity, and formation of a universal mRNA-protein (mRNP) granule called the Balbiani body...
2017: International Journal of Developmental Biology
https://www.readbyqxmd.com/read/28620033/scissor-sisters-regulation-of-adam10-by-the-tspanc8-tetraspanins
#11
REVIEW
Alexandra L Matthews, Justyna Szyroka, Richard Collier, Peter J Noy, Michael G Tomlinson
A disintegrin and metalloprotease 10 (ADAM10) is a ubiquitously expressed transmembrane protein which is essential for embryonic development through activation of Notch proteins. ADAM10 regulates over 40 other transmembrane proteins and acts as a 'molecular scissor' by removing their extracellular regions. ADAM10 is also a receptor for α-toxin, a major virulence factor of Staphylococcus aureus Owing to the importance of its substrates, ADAM10 is a potential therapeutic target for cancer, neurodegenerative diseases such as Alzheimer's and prion diseases, bacterial infection and inflammatory diseases such as heart attack, stroke and asthma...
June 15, 2017: Biochemical Society Transactions
https://www.readbyqxmd.com/read/28619160/protein-misfolding-cyclic-amplification-corroborates-the-absence-of-prp-sc-accumulation-in-placenta-from-foetuses-with-the-arr-arq-genotype-in-natural-scrapie
#12
María Carmen Garza, Hasier Eraña, Joaquín Castilla, Cristina Acín, Antonia Vargas, Juan José Badiola, Eva Monleón
Ovine scrapie is a worldwide spread prion disease that is transmitted horizontally under field conditions. Placenta from scrapie-infected ewes is an important source of infection, since this tissue can accumulate high amounts of PrP(Sc) depending on the foetal genotype. Therefore, placentas carrying susceptible foetuses can accumulate PrP(Sc) but there is not PrP(Sc) accumulation in presence of foetuses with at least one ARR haplotype. In scrapie eradication programs, ARR/ARR males are used for breeding to increase the resistant progeny and reduce the horizontal transmission of the disease through the placenta...
May 2017: Veterinary Microbiology
https://www.readbyqxmd.com/read/28614796/%C3%AE-synuclein-in-gut-endocrine-cells-and-its-implications-for-parkinson-s-disease
#13
Rashmi Chandra, Annie Hiniker, Yien-Ming Kuo, Robert L Nussbaum, Rodger A Liddle
Parkinson's disease (PD) is a progressive neurodegenerative disease with devastating clinical manifestations. In PD, neuronal death is associated with intracellular aggregates of the neuronal protein α-synuclein known as Lewy bodies. Although the cause of sporadic PD is not well understood, abundant clinical and pathological evidence show that misfolded α-synuclein is found in enteric nerves before it appears in the brain. This suggests a model in which PD pathology originates in the gut and spreads to the central nervous system via cell-to-cell prion-like propagation, such that transfer of misfolded α-synuclein initiates misfolding of native α-synuclein in recipient cells...
June 15, 2017: JCI Insight
https://www.readbyqxmd.com/read/28613153/precision-in-the-design-of-an-experimental-study-deflects-the-significance-of-proteinase-activated-receptor-2-expression-in-scrapie-inoculated-mice
#14
Zdenka Hanusova, Tibor Mosko, Radoslav Matej, Karel Holada
Proteinase-activated receptor 2 (PAR2) is suspected to modulate the pathogenesis of various neurodegenerative conditions. We previously described delayed onset of clinical symptoms and prolonged survival of PAR2-deficient mice after intracerebral inoculation with prions. Here we report the results from a refined blinded study that aimed to investigate the effects of PAR2 deletion on scrapie pathogenesis after peripheral infection. This study failed to confirm that PAR2 deficiency impacts on the length of the incubation period, with PAR2-/- and PAR2+/+ littermates developing scrapie at the same time...
June 14, 2017: Journal of General Virology
https://www.readbyqxmd.com/read/28611991/substrate-discrimination-by-clpb-and-hsp104
#15
Danielle M Johnston, Marika Miot, Joel R Hoskins, Sue Wickner, Shannon M Doyle
ClpB of E. coli and yeast Hsp104 are homologous molecular chaperones and members of the AAA+ (ATPases Associated with various cellular Activities) superfamily of ATPases. They are required for thermotolerance and function in disaggregation and reactivation of aggregated proteins that form during severe stress conditions. ClpB and Hsp104 collaborate with the DnaK or Hsp70 chaperone system, respectively, to dissolve protein aggregates both in vivo and in vitro. In yeast, the propagation of prions depends upon Hsp104...
2017: Frontiers in Molecular Biosciences
https://www.readbyqxmd.com/read/28610892/novel-human-neuronal-tau-model-exhibiting-neurofibrillary-tangles-and-transcellular-propagation
#16
Patrick Reilly, Charisse N Winston, Kelsey Baron, Margarita Trejo, Edward M Rockenstein, Johnny C Akers, Najla Kfoury, Marc Diamond, Eliezer Masliah, Robert A Rissman, Shauna H Yuan
Tauopathies are a class of neurodegenerative diseases, including Alzheimer's disease, frontotemporal dementia and progressive supranuclear palsy, that are associated with the pathological aggregation of tau protein in neurofibrillary tangles (NFT). Studies have characterized tau as a "prion-like" protein given its ability to form distinct, stable amyloid conformations capable of transcellular and multigenerational propagation in clonal fashion. It has been proposed that progression of tauopathy could be due to the prion-like propagation of tau, suggesting the possibility that end-stage pathologies like NFT formation may require an instigating event such as tau seeding...
June 10, 2017: Neurobiology of Disease
https://www.readbyqxmd.com/read/28607490/multiple-truncated-isoforms-of-mavs-prevent-its-spontaneous-aggregation-in-antiviral-innate-immune-signalling
#17
Nan Qi, Yuheng Shi, Rui Zhang, Wenting Zhu, Bofeng Yuan, Xiaoyan Li, Changwan Wang, Xuewu Zhang, Fajian Hou
In response to virus infection, RIG-I-like receptors (RLRs) sense virus RNA and induce MAVS to form prion-like aggregates to further propagate antiviral signalling. Although monomeric MAVS recombinant protein can assemble into prion-like filaments spontaneously in vitro, endogenous MAVS in cells is prevented from aggregation until viral infection. The mechanism preventing cellular MAVS from spontaneous aggregation is unclear. Here we show that multiple N-terminal truncated isoforms of MAVS are essential in preventing full-length MAVS from spontaneous aggregation through transmembrane domain-mediated homotypic interaction...
June 13, 2017: Nature Communications
https://www.readbyqxmd.com/read/28605958/the-first-report-of-prion-related-protein-gene-prnt-polymorphisms-in-goat
#18
Yong-Chan Kim, Byung-Hoon Jeong
Prion protein is encoded by the prion protein gene (PRNP). Polymorphisms of several members of the prion gene family have shown association with prion diseases in several species. Recent studies on a novel member of the prion gene family in rams have shown that prion-related protein gene (PRNT) has a linkage with codon 26 of prion-like protein (PRND). In a previous study, codon 26 polymorphism of PRND has shown connection with PRNP haplotype which is strongly associated with scrapie vulnerability. In addition, the genotype of a single nucleotide polymorphism (SNP) at codon 26 of PRND is related to fertilisation capacity...
June 2017: Acta Veterinaria Hungarica
https://www.readbyqxmd.com/read/28605901/graphite-templated-amyloid-nanostructures-formed-by-a-potential-pentapeptide-inhibitor-for-alzheimer-s-disease-a-combined-study-of-real-time-atomic-force-microscopy-and-molecular-dynamics-simulations
#19
Na Li, Hyunbum Jang, Ming Yuan, Wanrong Li, Xiaolin Yun, Joon Lee, Qiqige Du, Ruth Nussinov, Jiahua Hou, Ratnesh Lal, Feng Zhang
Self-assembly of peptides is closely related to many diseases, including Alzheimer's, Parkinson's, and prion diseases. Understanding the basic mechanism of this assembly is essential for designing ultimate cure and preventive measures. Template-assisted self-assembly (TASA) of peptides on inorganic substrates can provide fundamental understanding of substrate-dependent peptides assemble, including the role of hydrophobic interface on the peptide fibrillization. Here, we have studied the self-assembly process of a potential pentapeptide inhibitor on the surface of highly oriented pyrolytic graphite (HOPG) using real time atomic force microscopy (RT-AFM) as well as molecular dynamics (MD) simulation...
June 12, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28598840/neuropsychological-symptoms-in-sporadic-creutzfeldt-jakob-disease-patients-in-germany
#20
Anna Krasnianski, Geeske T Bohling, Uta Heinemann, Daniela Varges, Bettina Meissner, Walter J Schulz-Schaeffer, Andreas Reif, Inga Zerr
BACKGROUND: The polymorphism at codon 129 of the prion protein gene (PRNP) and the PrPSc types 1 and 2 belong to a molecular classification of sporadic Creutzfeldt-Jakob disease (sCJD) that correlates well with the clinical and neuropathological phenotype of sCJD. OBJECTIVE: The aim of the study was to perform the first detailed evaluation of neuropsychological deficits in a large group of definite sCJD patients with known molecular subtype. METHODS: We analyzed neuropsychological symptoms in a cohort of 248 sCJD patients with known M129 V polymorphism of PRNP and prion protein type...
June 8, 2017: Journal of Alzheimer's Disease: JAD
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