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Yunxiang Zang, Mingliang Jin, Huping Wang, Zhicheng Cui, Liangliang Kong, Caixuan Liu, Yao Cong
The eukaryotic chaperonin TRiC (or CCT) assists in the folding of 10% of cytosolic proteins. Here we present two cryo-EM structures of Saccharomyces cerevisiae TRiC in a newly identified nucleotide partially preloaded (NPP) state and in the ATP-bound state, at 4.7-Å and 4.6-Å resolution, respectively. Through inner-subunit eGFP tagging, we identified the subunit locations in open-state TRiC and found that the CCT2 subunit pair forms an unexpected Z shape. ATP binding induces a dramatic conformational change on the CCT2 side, thereby suggesting that CCT2 plays an essential role in TRiC allosteric cooperativity...
October 24, 2016: Nature Structural & Molecular Biology
Anne S Bie, Paula Fernandez-Guerra, Rune I D Birkler, Shahar Nisemblat, Dita Pelnena, Xinping Lu, Joshua L Deignan, Hane Lee, Naghmeh Dorrani, Thomas J Corydon, Johan Palmfeldt, Liga Bivina, Abdussalam Azem, Kristin Herman, Peter Bross
We here report molecular investigations of a missense mutation in the HSPE1 gene encoding the HSP10 subunit of the HSP60/ HSP10 chaperonin complex that assists protein folding in the mitochondrial matrix. The mutation was identified in an infant who came to clinical attention due to infantile spasms at 3 months of age. Clinical exome sequencing revealed heterozygosity for a HSPE1 NM_002157.2:c.217C>T de novo mutation causing replacement of leucine with phenylalanine at position 73 of the HSP10 protein. This variation has never been observed in public exome sequencing databases or the literature...
2016: Frontiers in Molecular Biosciences
Johnson Lin
Quantification of gene expression of Acinetobacter strain Y under 1000 mg/l of phenol was investigated using qPCR and proteomic analyses. The results show that Acinetobacter strain Y utilized 100 % of phenol within 18 h of exposure. The results of qPCR and proteomic analyses demonstrate a sequential expression of phenol-degrading genes of Acinetobacter strain Y via the ortho-pathway followed by the β-ketoadipate pathway. Many stress-responsive proteins such as chaperones, chaperonins, porins and the enzymes involved in the signal transduction pathway were upregulated especially in the early stage...
October 22, 2016: Archives of Microbiology
Nian Wei, Lili Hu, Lirong Song, Nanqin Gan
Micocystin (MC) exists in Microcystis cells in two different forms, free and protein-bound. We examined the dynamic change in extracellular free MCs, intracellular free MCs and protein-bound MCs in both batch cultures and semi-continuous cultures, using high performance liquid chromatography and Western blot. The results showed that the free MC per cell remained constant, while the quantity of protein-bound MCs increased with the growth of Microcystis cells in both kinds of culture. Significant changes in the dominant MC-bound proteins occurred in the late exponential growth phase of batch cultures, while the dominant MC-bound proteins in semi-continuous cultures remained the same...
October 12, 2016: Toxins
Naoya Fukui, Kiho Araki, Kunihiro Hongo, Tomohiro Mizobata, Yasushi Kawata
The isolated apical domain of the E. coli GroEL subunit displays the ability to suppress the irreversible fibrillation of numerous amyloid-forming polypeptides. In previous experiments, we have shown that mutating Gly192 (located at hinge II that connects the apical domain and the intermediate domain) to a tryptophan results in an inactive chaperonin whose apical domain is disoriented. In this study, we have utilized this disruptive effect of Gly192 mutation to our advantage, by substituting this residue with amino acid residues of varying Van der Waals volumes with the intent to modulate the affinity of GroEL toward fibrillogenic peptides...
October 14, 2016: Journal of Biological Chemistry
Miguel A Soler, Antonio Rey, Patrícia F N Faísca
The chaperonin complex GroEL-GroES is able to accelerate the folding process of knotted proteins considerably. However, the folding mechanism inside the chaperonin cage is elusive. Here we use a combination of lattice and off-lattice Monte Carlo simulations of simple Gō models to study the effect of physical confinement and local flexibility on the folding process of protein model systems embedding a trefoil knot in their native structure. This study predicts that steric confinement plays a specific role in the folding of knotted proteins by increasing the knotting probability for very high degrees of confinement...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
Sanofar Abdeen, Nilshad Salim, Najiba Mammadova, Corey M Summers, Karen Goldsmith-Pestana, Diane McMahon-Pratt, Peter G Schultz, Arthur L Horwich, Eli Chapman, Steven M Johnson
Trypanosoma brucei are protozoan parasites that cause African sleeping sickness in humans (also known as Human African Trypanosomiasis-HAT). Without treatment, T. brucei infections are fatal. There is an urgent need for new therapeutic strategies as current drugs are toxic, have complex treatment regimens, and are becoming less effective owing to rising antibiotic resistance in parasites. We hypothesize that targeting the HSP60/10 chaperonin systems in T. brucei is a viable anti-trypanosomal strategy as parasites rely on these stress response elements for their development and survival...
September 22, 2016: Bioorganic & Medicinal Chemistry Letters
Samuel Génier, Jade Degrandmaison, Pierrick Moreau, Pascale Labrecque, Terence E Hébert, Jean-Luc Parent
Mechanisms that prevent aggregation and promote folding of nascent G protein-coupled receptors (GPCRs) remain poorly understood. We identified CCT7 as an interacting partner of the β-isoform of thromboxane A2 receptor (TPβ) by yeast two-hybrid screening. CCT7 coimmunoprecipitated with overexpressed TPβ and β2-adrenergic receptor (β2AR) in HEK 293 cells, but also with endogenous β2AR. CCT7 depletion by siRNA reduced total and cell surface expression of both receptors, and caused redistribution of the receptors to juxta-nuclear aggresomes, significantly moreso for TPβ than β2AR...
October 5, 2016: Molecular Biology of the Cell
Kodai Machida, Tomoaki Shigeta, Ayano Kobayashi, Ai Masumoto, Yuna Hidaka, Hiroaki Imataka
Protein misfolding and aggregation is one of the major causes of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and Huntington's disease. So far protein aggregation related to these diseases has been studied using animals, cultured cells or purified proteins. In this study, we show that a newly synthesized polyglutamine protein implicated in Huntington's disease forms large aggregates in HeLa cells, and successfully recapitulate the process of this aggregation using a translation-based system derived from HeLa cell extracts...
October 1, 2016: Journal of Biotechnology
Ilia Korobko, Michal Nadler-Holly, Amnon Horovitz
The chaperonin-containing t-complex polypeptide 1 (CCT, also known as TRiC) assists protein folding in an ATP-dependent manner. CCT/TRiC was mixed rapidly with different concentrations of ATP, and the amount of phosphate formed upon ATP hydrolysis was measured as a function of time using the coumarin-labeled phosphate-binding protein method. Two burst phases were observed, followed by a lag phase and then a linear steady-state phase of ATP hydrolysis. The phases were assigned by (i) determining their dependence on ATP and K(+) concentrations and (ii) by measuring their sensitivity to the mutation Gly345→Asp in subunit CCT4, which decreases cooperativity in ATP binding...
September 26, 2016: Journal of Molecular Biology
Yuheng Yang, Yang Yu, Chaowei Bi, Zhensheng Kang
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is considered one of the most aggressive diseases to wheat production. In this study, we used an iTRAQ-based approach for the quantitative proteomic comparison of the incompatible Pst race CYR23 in infected and non-infected leaves of the wheat cultivar Suwon11. A total of 3,475 unique proteins were identified from three key stages of interaction (12, 24, and 48 h post-inoculation) and control groups. Quantitative analysis showed that 530 proteins were differentially accumulated by Pst infection (fold changes >1...
September 28, 2016: Scientific Reports
Shiladitya Chattopadhyay, Arpita Mukherjee, Upayan Patra, Rahul Bhowmick, Trayambak Basak, Shantanu Sengupta, Mamta Chawla-Sarkar
Phosphoproteomics-based platforms have been widely used to identify post translational dynamics of cellular proteins in response to viral infection. The present study was undertaken to assess differential tyrosine phosphorylation during early hours of rotavirus (RV) SA11 infection. Heat shock proteins (Hsp60) were found to be enriched in the data set of RV-SA11 induced differentially tyrosine-phosphorylated proteins at 2 hr post infection (hpi). Hsp60 was further found to be phosphorylated by an activated form of Src kinase on 227th tyrosine residue, and tyrosine phosphorylation of mitochondrial chaperonin Hsp60 correlated with its proteasomal degradation at 2-2...
September 24, 2016: Cellular Microbiology
Yuriko Minegishi, XunLun Sheng, Kazutoshi Yoshitake, Yuri Sergeev, Daisuke Iejima, Yoshio Shibagaki, Norikazu Monma, Kazuho Ikeo, Masaaki Furuno, Wenjun Zhuang, Yani Liu, Weining Rong, Seisuke Hattori, Takeshi Iwata
Leber congenital amaurosis (LCA) is a hereditary early-onset retinal dystrophy that is accompanied by severe macular degeneration. In this study, novel compound heterozygous mutations were identified as LCA-causative in chaperonin-containing TCP-1, subunit 2 (CCT2), a gene that encodes the molecular chaperone protein, CCTβ. The zebrafish mutants of CCTβ are known to exhibit the eye phenotype while its mutation and association with human disease have been unknown. The CCT proteins (CCT α-θ) forms ring complex for its chaperon function...
2016: Scientific Reports
Peter Bross, Paula Fernandez-Guerra
Heat shock protein 60 (HSP60) forms together with heat shock protein 10 (HSP10) double-barrel chaperonin complexes that are essential for folding to the native state of proteins in the mitochondrial matrix space. Two extremely rare monogenic disorders have been described that are caused by missense mutations in the HSPD1 gene that encodes the HSP60 subunit of the HSP60/HSP10 chaperonin complex. Investigations of the molecular mechanisms underlying these disorders have revealed that different degrees of reduced HSP60 function produce distinct neurological phenotypes...
2016: Frontiers in Molecular Biosciences
Aswathy N, Dileep Pullepu, M Anaul Kabir
The eukaryotic chaperonin, CCT (Chaperonin Containing TCP1 or TriC-TCP-1 Ring Complex) has been subjected to physical and genetic analyses in S. cerevisiae which can be extrapolated to human CCT (hCCT), owing to its structural and functional similarities with yeast CCT (yCCT). Studies on hCCT and its interactome acquire an additional dimension, as it has been implicated in several disease conditions like neurodegeneration and cancer. We attempt to study its stress response role in general, which will be reflected in the aspects of human diseases and yeast physiology, through computational analysis of the interactome...
September 6, 2016: Computational Biology and Chemistry
Victor Midlej, Luciana Penha, Rosane Silva, Wanderley de Souza, Marlene Benchimol
The mitosome is a double-membrane enveloped organelle that is found in few unicellular eukaryotes, one of which is the human intestinal parasitic protist Giardia intestinalis, which also lacks mitochondria and peroxisomes. This flagellated protist grows in vitro as trophozoites and under some conditions, differentiates into cysts, which are characterized by the absence of externalized flagella, a round shape, and the presence of a cyst wall. The presence and distribution of mitosomal proteins, such as giardial iron-sulfur cluster protein (GiIscU), heat-shock protein 70 (mit-HSP70) and giardial chaperonin 60 (GiCpn60), during the process of trophozoite-to-cyst transformation was tracked using confocal laser scanning microscopy and western blotting...
August 31, 2016: European Journal of Cell Biology
Xiaobei Zhao, Xu-Qiao Chen, Eugene Han, Yue Hu, Paul Paik, Zhiyong Ding, Julia Overman, Alice L Lau, Sarah H Shahmoradian, Wah Chiu, Leslie M Thompson, Chengbiao Wu, William C Mobley
Corticostriatal atrophy is a cardinal manifestation of Huntington's disease (HD). However, the mechanism(s) by which mutant huntingtin (mHTT) protein contributes to the degeneration of the corticostriatal circuit is not well understood. We recreated the corticostriatal circuit in microfluidic chambers, pairing cortical and striatal neurons from the BACHD model of HD and its WT control. There were reduced synaptic connectivity and atrophy of striatal neurons in cultures in which BACHD cortical and striatal neurons were paired...
September 20, 2016: Proceedings of the National Academy of Sciences of the United States of America
Giuseppe Morici, Monica Frinchi, Alessandro Pitruzzella, Valentina Di Liberto, Rosario Barone, Andrea Pace, Valentina Di Felice, Natale Belluardo, Francesco Cappello, Giuseppa Mudò, Maria R Bonsignore
In the mdx mice model of Duchenne Muscular Dystrophy (DMD), mild endurance exercise training positively affected limb skeletal muscles, whereas few and controversial data exist on the effects of training on the diaphragm. The diaphragm was examined in mdx (C57BL/10ScSn-Dmdmdx) and wild type (WT, C57BL/10ScSc) mice under sedentary conditions (mdx-SD, WT-SD) and during mild exercise training (mdx-EX, WT-EX). At baseline, and after 30 and 45 days (training: 5 d/wk for 6 weeks), diaphragm muscle morphology and Cx39 protein were assessed...
August 30, 2016: Journal of Cellular Physiology
Michele M Lynch, Jichuan Liu, Michael Nigra, Marc-Olivier Coppens
While enzymes are valuable tools in many fields of biotechnology, they are fragile and must be protected against denaturing conditions such as unfavorable solution pH. Within living organisms, chaperonins help enzymes fold into their native shape and protect them from damage. Inspired by this natural solution, mesoporous silica SBA-15 with different pore diameters is synthesized as a support material for immobilizing and protecting enzymes. In separate experiments, the model enzymes myoglobin and lysozyme are physically adsorbed to SBA-15 and exposed to a range of buffered pH conditions...
September 20, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Seunghyun Sim, Tatsuya Niwa, Hideki Taguchi, Takuzo Aida
How to modulate supramolecular protein nanotubes without sacrificing their thermodynamic stability? This challenging issue emerged with an enhanced reality since our successful development of a protein nanotube of chaperonin GroELMC as a novel ATP-responsive 1D nanocarrier because the nanotube length may potentially affect the cellular uptake efficiency. Herein, we report a molecularly engineered protein end-capper (SRMC) that firmly binds to the nanotube termini since the end-capper originates from GroEL. According to the single-ring mutation of GroEL, we obtained a single-ring version of GroEL bearing cysteine mutations (GroELCys) and modified its 14 apical cysteine residues with merocyanine (MC)...
September 7, 2016: Journal of the American Chemical Society
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