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Dario Spigolon, D Travis Gallagher, Adrian Velazquez-Campoy, Donatella Bulone, Jatin Narang, Pier Luigi San Biagio, Francesco Cappello, Alberto J L Macario, Everly Conway de Macario, Frank T Robb
The human chaperonin complex is a ~ 1 MDa nanomachine composed of two octameric rings formed from eight similar but non-identical subunits called CCT. Here, we are elucidating the mechanism of a heritable CCT5 subunit mutation that causes profound neuropathy in humans. In previous work, we introduced an equivalent mutation in an archaeal chaperonin that assembles into two octameric rings like in humans but in which all subunits are identical. We reported that the hexadecamer formed by the mutant subunit is unstable with impaired chaperoning functions...
December 2017: Biochemistry and Biophysics Reports
Yani Zhao, Pawel Dabrowski-Tumanski, Szymon Niewieczerzal, Joanna I Sulkowska
The folding of proteins with a complex knot is still an unresolved question. Based on representative members of Ubiquitin C-terminal Hydrolases (UCHs) that contain the 52 knot in the native state, we explain how UCHs are able to unfold and refold in vitro reversibly within the structure-based model. In particular, we identify two, topologically different folding/unfolding pathways and corroborate our results with experiment, recreating the chevron plot. We show that confinement effect of chaperonin or weak crowding greatly facilitates folding, simultaneously slowing down the unfolding process of UCHs, compared with bulk conditions...
March 16, 2018: PLoS Computational Biology
Genki Yoshikawa, Ahmed Askora, Romain Blanc-Mathieu, Takeru Kawasaki, Yanze Li, Miyako Nakano, Hiroyuki Ogata, Takashi Yamada
Xanthomonas virus (phage) XacN1 is a novel jumbo myovirus infecting Xanthomonas citri, the causative agent of Asian citrus canker. Its linear 384,670 bp double-stranded DNA genome encodes 592 proteins and presents the longest (66 kbp) direct terminal repeats (DTRs) among sequenced viral genomes. The DTRs harbor 56 tRNA genes, which correspond to all 20 amino acids and represent the largest number of tRNA genes reported in a viral genome. Codon usage analysis revealed a propensity for the phage encoded tRNAs to target codons that are highly used by the phage but less frequently by its host...
March 14, 2018: Scientific Reports
Jonathan J Knowlton, Isabel Fernández de Castro, Alison W Ashbrook, Daniel R Gestaut, Paula F Zamora, Joshua A Bauer, J Craig Forrest, Judith Frydman, Cristina Risco, Terence S Dermody
Viruses are molecular machines sustained through a life cycle that requires replication within host cells. Throughout the infectious cycle, viral and cellular components interact to advance the multistep process required to produce progeny virions. Despite progress made in understanding the virus-host protein interactome, much remains to be discovered about the cellular factors that function during infection, especially those operating at terminal steps in replication. In an RNA interference screen, we identified the eukaryotic chaperonin T-complex protein-1 (TCP-1) ring complex (TRiC; also called CCT for chaperonin containing TCP-1) as a cellular factor required for late events in the replication of mammalian reovirus...
March 12, 2018: Nature Microbiology
Alex Pines, Madelon Dijk, Matthew Makowski, Elisabeth M Meulenbroek, Mischa G Vrouwe, Yana van der Weegen, Marijke Baltissen, Pim J French, Martin E van Royen, Martijn S Luijsterburg, Leon H Mullenders, Michiel Vermeulen, Wim Vermeulen, Navraj S Pannu, Haico van Attikum
Transcription-blocking DNA lesions are removed by transcription-coupled nucleotide excision repair (TC-NER) to preserve cell viability. TC-NER is triggered by the stalling of RNA polymerase II at DNA lesions, leading to the recruitment of TC-NER-specific factors such as the CSA-DDB1-CUL4A-RBX1 cullin-RING ubiquitin ligase complex (CRLCSA ). Despite its vital role in TC-NER, little is known about the regulation of the CRLCSA complex during TC-NER. Using conventional and cross-linking immunoprecipitations coupled to mass spectrometry, we uncover a stable interaction between CSA and the TRiC chaperonin...
March 12, 2018: Nature Communications
Corinna Konieczna, Agnieszka Olejnik-Schmidt, Marcin T Schmidt
BACKGROUND: n. Adhesion of bacteria from the genus Lactobacillus to the gastrointestinal epithelium is, to a considerable degree, dependent on the interactions between adhesins found on the surface of bacterial cells and elements found within the epithelium. A significant role in these interactions is played by bacterial pro teins exposed to the cell wall surface, which are capable of binding to molecules of substances comprising the extracellular matrix of the intestinal epithelium. METHODS: In order to analyze the extracellular proteome of intestinal bacteria in terms of the presence of cell adhesion molecules, a total of twenty strains from the Lactobacillus spp...
January 2018: Acta Scientiarum Polonorum. Technologia Alimentaria
N A Ryabova, O M Selivanova, G V Semisotnov
The products of the reassembly reaction of tetradecameric two-ring quaternary structure of GroEL chaperonin under the pressure of its heptameric co-chaperonin GroES have been visualized by electron microscopy. It has been shown that one-ring heptameric oligomers of GroEL have been formed at the beginning (after ~5 min) of the reaction, while at the final stage of the reaction (after ~70 min), both one-ring heptamers in complex with one GroES and two-rings tetradecamers in complexes with one (asymmetrical complex) or two (symmetrical complex) GroES heptamers are present...
January 2018: Molekuliarnaia Biologiia
Hanna E Sidjabat, Jolene Gien, David Kvaskoff, Keith Ashman, Kanchan Vaswani, Sarah Reed, Ross P McGeary, David L Paterson, Amanda Bordin, Gerhard Schenk
Antibiotic resistance associated with the clinically significant carbapenemases KPC, NDM and OXA-48 in Enterobacteriaceae is emerging as worldwide. In Australia, IMP-producing Enterobacteriaceae are the most prevalent carbapenemase-producing Enterobacteriaceae (CPE). Genomic characteristics of such CPE are well described, but the corresponding proteome is poorly characterised. We have thus developed a method to analyse dynamic changes in the proteome of CPE under antibiotic pressure. Specifically, we have investigated the effect of meropenem at sub-lethal concentrations to develop a better understanding of how antibiotic pressure leads to resistance...
March 1, 2018: Scientific Reports
Kazuhiko Tatemoto, Yuko Nozaki, Ryoko Tsuda, Shinobu Kaneko, Keiko Tomura, Masahiro Furuno, Hiroyuki Ogasawara, Koji Edamura, Hideo Takagi, Hiroyuki Iwamura, Masato Noguchi, Takayuki Naito
Mast cells play a central role in inflammatory and allergic reactions by releasing inflammatory mediators through two main pathways, immunoglobulin E-dependent and -independent activation. In the latter pathway, mast cells are activated by a diverse range of basic molecules (collectively known as basic secretagogues) through Mas-related G protein-coupled receptors (MRGPRs). In addition to the known basic secretagogues, here, we discovered several endogenous protein and enzyme fragments (such as chaperonin-10 fragment, etc...
February 27, 2018: Scandinavian Journal of Immunology
Tomasz Wenta, Dorota Zurawa-Janicka, Michal Rychlowski, Miroslaw Jarzab, Przemyslaw Glaza, Andrea Lipinska, Krystyna Bienkowska-Szewczyk, Anna Herman-Antosiewicz, Joanna Skorko-Glonek, Barbara Lipinska
The human HtrA3 protease is involved in placentation, mitochondrial homeostasis, stimulation of apoptosis and proposed to be a tumor suppressor. Molecular mechanisms of the HtrA3 functions are poorly understood and knowledge concerning its cellular targets is very limited. There are two HtrA3 isoforms, the long (HtrA3L) and short (HtrA3S). Upon stress, their N-terminal domains are removed, resulting in the more active ΔN-HtrA3. By pull down and mass spectrometry techniques, we identified a panel of putative ΔN-HtrA3L/S substrates...
February 22, 2018: Journal of Proteomics
Yuriko Minegishi, Naoki Nakaya, Stanislav I Tomarev
Purpose: The compound heterozygous mutations in the β subunit of chaperonin containing TCP-1 (CCT), encoded by CCT2, lead to the Leber congenital amaurosis (LCA). In this study, a cct2 mutant line of zebrafish was established to investigate the role of CCT2 mutations in LCA in vertebrates. Methods: A cct2 mutant zebrafish line was produced using the CRISPR-Cas9 system. Changes in the eyes of developing wild-type and mutant larvae were monitored using microscopy, immunostaining, TUNEL, and EdU assays...
February 1, 2018: Investigative Ophthalmology & Visual Science
Srdja Drakulic, Jay Rai, Steen Vang Petersen, Monika M Golas, Bjoern Sander
The pyruvate dehydrogenase complex (PDC) bridges glycolysis and the citric acid cycle. In human, PDC deficiency leads to severe neurodevelopmental delay and progressive neurodegeneration. The majority of cases are caused by variants in the gene encoding the PDC subunit E1α. The molecular effects of the variants, however, remain poorly understood. Using yeast as a eukaryotic model system, we have studied the substitutions A189V, M230V, and R322C in yeast E1α (corresponding to the pathogenic variants A169V, M210V, and R302C in human E1α) and evaluated how substitutions of single amino acid residues within different functional E1α regions affect PDC structure and activity...
February 14, 2018: Cellular and Molecular Life Sciences: CMLS
Dominik Schwarz, Orit Adato, Amnon Horovitz, Ron Unger
The GroE chaperonin system, which comprises GroEL and GroES, assists protein folding in vivo and in vitro. It is conserved in all prokaryotes except in most, but not all, members of the class of mollicutes. In Escherichia coli, about 60 proteins were found to be obligatory clients of the GroE system. Here, we describe the properties of the homologs of these GroE clients in mollicutes and the evolution of chaperonins in this class of bacteria. Comparing the properties of these homologs in mollicutes with and without chaperonins enabled us to search for features correlated with the presence of GroE...
2018: PloS One
Anna Vitlin Gruber, Milena Vugman, Abdussalam Azem, Celeste E Weiss
Chaperonins are large, essential, oligomers that facilitate protein folding in chloroplasts, mitochondria, and eubacteria. Plant chloroplast chaperonins are comprised of multiple homologous subunits that exhibit unique properties. We previously characterized homogeneous, reconstituted, chloroplast-chaperonin oligomers in vitro, each composed of one of three highly homologous beta subunits from A. thaliana. In the current work, we describe alpha-type subunits from the same species and investigate their interaction with β subtypes...
2018: Frontiers in Molecular Biosciences
Zhihao Zhang, Liping Xu, Changyu Sun
The present study was performed to detect moderate or low-frequency mutated cancer driver genes in hepatocellular carcinoma (HCC), using OncodriveFM and Dendrix. Following this, integrated analyses were conducted on these novel cancer driver genes. A total of 112,980 somatic mutations were retrieved from TCGA and classified into 11 categories based on their function. Driver genes and pathways were predicted by OncodriveFM and Dendrix, followed by differential expression, DNA-methylation, copy number variations and survival analyses...
February 2018: Oncology Letters
Muhamad Sahlan, Tamotsu Zako, Masafumi Yohda
Prefoldin is a hexameric molecular chaperone found in the cytosol of archaea and eukaryotes. Its hexameric complex is built from two related classes of subunits and has the appearance of a jellyfish: its body consists of a double beta-barrel assembly with six long tentacle-like coiled coils protruding from it. Using the tentacles, prefoldin captures an unfolded protein substrate and transfers it to a group II chaperonin. The prefoldin-group II chaperonin system is thought to be important for the folding of newly synthesized proteins and for their maintenance, or proteostasis, in the cytosol...
February 9, 2018: Biophysical Reviews
Ryuichi Ishida, Tomoya Okamoto, Fumihiro Motojima, Hiroshi Kubota, Hiroki Takahashi, Masako Tanabe, Toshihiko Oka, Akira Kitamura, Masataka Kinjo, Masasuke Yoshida, Michiro Otaka, Ewa Grave, Hideaki Itoh
The E. coli GroEL/GroES chaperonin complex acts as a folding cage by producing a bullet-like asymmetric complex, and GroEL exists as double rings regardless of the presence of adenosine triphosphate (ATP). Its mammalian chaperonin homolog, heat shock protein, HSP60, and co-chaperonin, HSP10, play an essential role in protein folding by capturing unfolded proteins in the HSP60/HSP10 complex. However, the structural transition in ATPase-dependent reaction cycle has remained unclear. We found nucleotide-dependent association and dissociation of the HSP60/HSP10 complex using various analytical techniques under near physiological conditions...
February 6, 2018: International Journal of Molecular Sciences
Yunxiang Zang, Huping Wang, Zhicheng Cui, Mingliang Jin, Caixuan Liu, Wenyu Han, Yanxing Wang, Yao Cong
Unambiguous subunit assignment in a multicomponent complex is critical for thorough understanding of the machinery and its functionality. The eukaryotic group II chaperonin TRiC/CCT folds approximately 10% of cytosolic proteins and is important for the maintenance of cellular homeostasis. TRiC consists of two rings and each ring has eight homologous but distinct subunits. Unambiguous subunit identification of a macromolecular machine such as TRiC through intermediate or low-resolution cryo-EM map remains challenging...
February 5, 2018: Scientific Reports
Li-Juan Li, Lian-Sheng Zhang, Zhi-Jian Han, Zhi-Yun He, Hao Chen, Yu-Min Li
Background: Members of eukaryotic chaperonin family are essential for cell survival. Dysregulation of Chaperonin containing TCP-1 subunit 3 (CCT3) has been implicated in the development of several types of cancers. However, the role of CCT3 in the development of gastric cancer has yet to be determined. Methods: The expression patterns of CCT3 in the surgical specimens from 26 gastric cancer patients were evaluated using immunohistochemistry methods. To study the possible roles of CCT3 in the growth and survival of gastric cancer cells, RNA interference was used to knockdown CCT3 expression in gastric cancer cell lines BGC-823 and MGC-803...
December 19, 2017: Oncotarget
Luis Pouchucq, Pablo Lobos-Ruiz, Gisela Araya, José María Valpuesta, Octavio Monasterio
The type II chaperonin CCT is involved in the prevention of the pathogenesis of numerous human misfolding disorders, as it sequesters misfolded proteins, blocks their aggregation and helps them to achieve their native state. In addition, it has been reported that CCT can prevent the toxicity of non-client amyloidogenic proteins by the induction of non-toxic aggregates, leading to new insight in chaperonin function as an aggregate remodeling factor. Here we add experimental evidence to this alternative mechanism by which CCT actively promotes the formation of conformationally different aggregates of γ-tubulin, a non-amyloidogenic CCT client protein, which are mediated by specific CCT-γ-tubulin interactions...
January 12, 2018: Biochimica et Biophysica Acta
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