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Protein unfolding and translocation

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https://www.readbyqxmd.com/read/28988953/meddling-with-fate-the-proteasomal-deubiquitinating-enzymes
#1
REVIEW
Stefanie A H de Poot, Geng Tian, Daniel Finley
Three deubiquitinating enzymes-Rpn11, Usp14, and Uch37-are associated with the proteasome regulatory particle. These enzymes allow proteasomes to remove ubiquitin from substrates before they are translocated into the core particle to be degraded. Although the translocation channel is too narrow for folded proteins, the force of translocation unfolds them mechanically. As translocation proceeds, ubiquitin chains bound to substrate are drawn to the channel's entry port, where they can impede further translocation...
October 5, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28980803/analysis-of-pore-formation-and-protein-translocation-using-large-biological-nanopores
#2
Hirokazu Watanabe, Alberto Gubbiotti, Mauro Chinappi, Natsumi Takai, Koji Tanaka, Kouhei Tsumoto, Ryuji Kawano
This paper describes the analysis of pore formation and detection of a single protein molecule using a large nanopore among five different pore-forming proteins. We demonstrate that the identification of appropriate pores for nanopore sensing can be achieved by classifying the channel current signals and performing noise analysis. Through these analyses, we selected a perforin nanopore from the membrane attack complex/perforin superfamily and attempted to use it to detect the granzyme B protein, a serine protease...
October 5, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28978049/ros-independent-nrf2-activation-in-prostate-cancer
#3
Ilaria Bellezza, Paolo Scarpelli, Salvatore V Pizzo, Silvia Grottelli, Egidia Costanzi, Alba Minelli
In prostate cancer, oxidative stress and the subsequent Nrf2 activation promote the survival of cancer cells and acquired chemoresistance. Nrf2 links prostate cancer to endoplasmic reticulum stress, an event that triggers the unfolded protein response, aiming to restore cellular homeostasis as well as an adaptive survival mechanism. Glucose-regulated protein of 78 kD /immunoglobulin heavy chain binding protein (GRP78/BiP) is a key molecular chaperone in the endoplasmic reticulum that, when expressed at the cell surface, acts as a receptor for several signaling pathways enhancing antiapoptotic and proliferative signals...
September 15, 2017: Oncotarget
https://www.readbyqxmd.com/read/28920507/navigating-the-structure-function-evolutionary-relationship-of-csaa-chaperone-in-archaea
#4
Archana Sharma, Shikha Rani, Manisha Goel
CsaA is a protein involved in the post-translational translocation of proteins across the cytoplasmic membrane. It is considered to be a functional homolog of SecB which participates in the Sec-dependent translocation pathway in an analogous manner. CsaA has also been reported to act as a molecular chaperone, preventing aggregation of unfolded proteins. It is essentially a prokaryotic protein which is absent in eukaryotes, but found extensively in bacteria and earlier thought to be widely present in archaea...
September 18, 2017: Critical Reviews in Microbiology
https://www.readbyqxmd.com/read/28904818/nf-%C3%AE%C2%BAb-pathway-link-with-er-stress-induced-autophagy-and-apoptosis-in-cervical-tumor-cells
#5
Xiaolan Zhu, Li Huang, Jie Gong, Chun Shi, Zhiming Wang, Bingkun Ye, Aiguo Xuan, Xiaosong He, Dahong Long, Xiao Zhu, Ningfang Ma, Shuilong Leng
Targeting endoplasmic reticulum (ER) stress is being investigated for its anticancer effect in various cancers, including cervical cancer. However, the molecular pathways whereby ER stress mediates cell death remain to be fully elucidated. In this study, we confirmed that ER stress triggered by compounds such as brefeldin A (BFA), tunicamycin (TM), and thapsigargin (TG) leads to the induction of the unfolded protein response (UPR) in cervical cancer cell lines, which is characterized by elevated levels of inositol-requiring kinase 1α, glucose-regulated protein-78, and C/EBP homologous protein, and swelling of the ER observed by transmission electron microscope (TEM)...
2017: Cell Death Discovery
https://www.readbyqxmd.com/read/28878026/the-p97-inhibitor-cb-5083-is-a-unique-disrupter-of-protein-homeostasis-in-models-of-multiple-myeloma
#6
Ronan Le Moigne, Blake T Aftab, Stevan Djakovic, Eugen Dhimolea, Eduardo Valle, Megan Murnane, Emily M King, Ferdie Soriano, Mary-Kamala Menon, Zhi Yong Wu, Stephen T Wong, Grace J Lee, Bing Yao, Arun P Wiita, Christine Lam, Julie Rice, Jinhai Wang, Marta Chesi, P Leif Bergsagel, Marianne Kraus, Christoph Driessen, Szerenke Kiss von Soly, F Michael Yakes, David Wustrow, Laura Shawver, Han-Jie Zhou, Thomas G Martin, Jeffrey L Wolf, Constantine S Mitsiades, Daniel J Anderson, Mark Rolfe
Inhibition of the AAA ATPase, p97, was recently shown to be a novel method for targeting the ubiquitin proteasome system (UPS) and CB-5083, a first in class inhibitor of p97, has demonstrated broad antitumor activity in a range of both hematological and solid tumor models. Here, we show that CB-5083 has robust activity against multiple myeloma (MM) cell lines and a number of in vivo MM models. Treatment with CB-5083 is associated with accumulation of ubiquitinated proteins, induction of the unfolded protein response (UPR) and apoptosis...
September 6, 2017: Molecular Cancer Therapeutics
https://www.readbyqxmd.com/read/28844860/an-aaa-motor-driven-mechanical-switch-in-rpn11-controls-deubiquitination-at-the-26s-proteasome
#7
Evan J Worden, Ken C Dong, Andreas Martin
Poly-ubiquitin chains direct protein substrates to the 26S proteasome, where they are removed by the deubiquitinase Rpn11 during ATP-dependent substrate degradation. Rapid deubiquitination is required for efficient degradation but must be restricted to committed substrates that are engaged with the ATPase motor to prevent premature ubiquitin chain removal and substrate escape. Here we reveal the ubiquitin-bound structure of Rpn11 from S. cerevisiae and the mechanisms for mechanochemical coupling of substrate degradation and deubiquitination...
September 7, 2017: Molecular Cell
https://www.readbyqxmd.com/read/28815021/toward-an-understanding-of-the-cdc48-p97-atpase
#8
REVIEW
Nicholas Bodnar, Tom Rapoport
A conserved AAA+ ATPase, called Cdc48 in yeast and p97 or VCP in metazoans, plays an essential role in many cellular processes by segregating polyubiquitinated proteins from complexes or membranes. For example, in endoplasmic reticulum (ER)-associated protein degradation (ERAD), Cdc48/p97 pulls polyubiquitinated, misfolded proteins out of the ER and transfers them to the proteasome. Cdc48/p97 consists of an N-terminal domain and two ATPase domains (D1 and D2). Six Cdc48 monomers form a double-ring structure surrounding a central pore...
2017: F1000Research
https://www.readbyqxmd.com/read/28811582/a-new-class-of-hybrid-secretion-system-is-employed-in-pseudomonas-amyloid-biogenesis
#9
Sarah L Rouse, William J Hawthorne, Jamie-Lee Berry, Dror S Chorev, Sandra A Ionescu, Sebastian Lambert, Fisentzos Stylianou, Wiebke Ewert, Uma Mackie, R Marc L Morgan, Daniel Otzen, Florian-Alexander Herbst, Per H Nielsen, Morten Dueholm, Hagan Bayley, Carol V Robinson, Stephen Hare, Stephen Matthews
Gram-negative bacteria possess specialised biogenesis machineries that facilitate the export of amyloid subunits for construction of a biofilm matrix. The secretion of bacterial functional amyloid requires a bespoke outer-membrane protein channel through which unfolded amyloid substrates are translocated. Here, we combine X-ray crystallography, native mass spectrometry, single-channel electrical recording, molecular simulations and circular dichroism measurements to provide high-resolution structural insight into the functional amyloid transporter from Pseudomonas, FapF...
August 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/28782633/plasma-cell-deficiency-in-human-subjects-with-heterozygous-mutations-in-sec61-translocon-alpha-1-subunit-sec61a1
#10
Desirée Schubert, Marie-Christine Klein, Sarah Hassdenteufel, Andrés Caballero-Oteyza, Linlin Yang, Michele Proietti, Alla Bulashevska, Janine Kemming, Johannes Kühn, Sandra Winzer, Stephan Rusch, Manfred Fliegauf, Alejandro A Schäffer, Stefan Pfeffer, Roger Geiger, Adolfo Cavalié, Hongzhi Cao, Fang Yang, Yong Li, Marta Rizzi, Hermann Eibel, Robin Kobbe, Amy L Marks, Brian P Peppers, Robert W Hostoffer, Jennifer M Puck, Richard Zimmermann, Bodo Grimbacher
BACKGROUND: Primary antibody deficiencies (PADs) are the most frequent primary immunodeficiencies in human subjects. The genetic causes of PADs are largely unknown. Sec61 translocon alpha 1 subunit (SEC61A1) is the major subunit of the Sec61 complex, which is the main polypeptide-conducting channel in the endoplasmic reticulum membrane. SEC61A1 is a target gene of spliced X-box binding protein 1 and strongly induced during plasma cell (PC) differentiation. OBJECTIVE: We identified a novel genetic defect and studied its pathologic mechanism in 11 patients from 2 unrelated families with PADs...
August 4, 2017: Journal of Allergy and Clinical Immunology
https://www.readbyqxmd.com/read/28776058/sds-assisted-protein-transport-through-solid-state-nanopores
#11
Laura Restrepo-Pérez, Shalini John, Aleksei Aksimentiev, Chirlmin Joo, Cees Dekker
Using nanopores for single-molecule sequencing of proteins - similar to nanopore-based sequencing of DNA - faces multiple challenges, including unfolding of the complex tertiary structure of the proteins and enforcing their unidirectional translocation through nanopores. Here, we combine molecular dynamics (MD) simulations with single-molecule experiments to investigate the utility of SDS (Sodium Dodecyl Sulfate) to unfold proteins for solid-state nanopore translocation, while simultaneously endowing them with a stronger electrical charge...
August 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/28724722/effect-of-directional-pulling-on-mechanical-protein-degradation-by-atp-dependent-proteolytic-machines
#12
Adrian O Olivares, Hema Chandra Kotamarthi, Benjamin J Stein, Robert T Sauer, Tania A Baker
AAA+ proteases and remodeling machines couple hydrolysis of ATP to mechanical unfolding and translocation of proteins following recognition of sequence tags called degrons. Here, we use single-molecule optical trapping to determine the mechanochemistry of two AAA+ proteases, Escherichia coli ClpXP and ClpAP, as they unfold and translocate substrates containing multiple copies of the titin(I27) domain during degradation initiated from the N terminus. Previous studies characterized degradation of related substrates with C-terminal degrons...
July 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28706146/ros-independent-nrf2-activation-in-prostate-cancer
#13
Ilaria Bellezza, Paolo Scarpelli, Salvatore V Pizzo, Silvia Grottelli, Egidia Costanzi, Alba Minelli
In prostate cancer, oxidative stress and the subsequent Nrf2 activation promote the survival of cancer cells and acquired chemoresistance. Nrf2 links prostate cancer to endoplasmic reticulum stress, an event that triggers the unfolded protein response, aiming to restore cellular homeostasis as well as an adaptive survival mechanism. Glucose-regulated protein of 78 kD /immunoglobulin heavy chain binding protein (GRP78/BiP) is a key molecular chaperone in the endoplasmic reticulum that, when expressed at the cell surface, acts as a receptor for several signaling pathways enhancing antiapoptotic and proliferative signals...
June 28, 2017: Oncotarget
https://www.readbyqxmd.com/read/28676851/aaa-atpases-in-protein-degradation
#14
REVIEW
Ravikiran S Yedidi, Petra Wendler, Cordula Enenkel
Proteolytic machineries containing multisubunit protease complexes and AAA-ATPases play a key role in protein quality control and the regulation of protein homeostasis. In these protein degradation machineries, the proteolytically active sites are formed by either threonines or serines which are buried inside interior cavities of cylinder-shaped complexes. In eukaryotic cells, the proteasome is the most prominent protease complex harboring AAA-ATPases. To degrade protein substrates, the gates of the axial entry ports of the protease need to be open...
2017: Frontiers in Molecular Biosciences
https://www.readbyqxmd.com/read/28675036/asymmetric-conformational-transitions-in-aaa-biological-nanomachines-modulate-direction-dependent-substrate-protein-unfolding-mechanisms
#15
Abdolreza Javidialesaadi, George Stan
Powerful AAA+ biological nanomachines, such as ClpY, form hexameric ring structures, which selectively process abnormal proteins targeted for degradation by unfolding and threading them through a narrow central channel. The molecular details of this process are not yet fully understood. We perform Langevin dynamics simulations using a coarse-grained model of substrate proteins (SPs), Titin I27 and its V13P variant, threading through the ClpY pore. We probe the effect of ClpY surface heterogeneity and changes in pore width on SP orientation and the direction of applied force during SP unfolding...
July 27, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28670265/the-endoplasmic-reticulum-unfolded-protein-response-in-neurodegenerative-disorders-and-its-potential-therapeutic-significance
#16
REVIEW
Paolo Remondelli, Maurizio Renna
In eukaryotic cells, the endoplasmic reticulum (ER) is the cell compartment involved in secretory protein translocation and quality control of secretory protein folding. Different conditions can alter ER function, resulting in the accumulation of unfolded or misfolded proteins within the ER lumen. Such a condition, known as ER stress, elicits an integrated adaptive response known as the unfolded protein response (UPR) that aims to restore proteostasis within the secretory pathway. Conversely, in prolonged cell stress or insufficient adaptive response, UPR signaling causes cell death...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/28624220/tat-hafgf14-154-upregulates-adam10-to-attenuate-the-alzheimer-phenotype-of-app-ps1-mice-through-the-pi3k-creb-ire1%C3%AE-xbp1-pathway
#17
Tian Meng, Qin Cao, Peng Lei, Ashley I Bush, Qi Xiang, Zhijian Su, Xiang He, Jack T Rogers, Ing-Ming Chiu, Qihao Zhang, Yadong Huang
Acid fibroblast growth factor (aFGF) has shown neuroprotection in Alzheimer's disease (AD) models in previous studies, yet its mechanism is still uncertain. Here we report that the efficacy of Tat-haFGF14-154 is markedly increased when loaded cationic liposomes for intranasal delivery are intranasally administered to APP/PS1 mice. Our results demonstrated that liposomal Tat-haFGF14-154 treatment significantly ameliorated behavioral deficits, relieved brain Aβ burden, and increased the expression and activity of disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) in the brain...
June 16, 2017: Molecular Therapy. Nucleic Acids
https://www.readbyqxmd.com/read/28619716/ratchet-like-polypeptide-translocation-mechanism-of-the-aaa-disaggregase-hsp104
#18
Stephanie N Gates, Adam L Yokom, JiaBei Lin, Meredith E Jackrel, Alexandrea N Rizo, Nathan M Kendsersky, Courtney E Buell, Elizabeth A Sweeny, Korrie L Mack, Edward Chuang, Mariana P Torrente, Min Su, James Shorter, Daniel R Southworth
Hsp100 polypeptide translocases are conserved members of the AAA+ family (adenosine triphosphatases associated with diverse cellular activities) that maintain proteostasis by unfolding aberrant and toxic proteins for refolding or proteolytic degradation. The Hsp104 disaggregase from Saccharomyces cerevisiae solubilizes stress-induced amorphous aggregates and amyloids. The structural basis for substrate recognition and translocation is unknown. Using a model substrate (casein), we report cryo-electron microscopy structures at near-atomic resolution of Hsp104 in different translocation states...
July 21, 2017: Science
https://www.readbyqxmd.com/read/28583440/proteasome-structure-and-assembly
#19
REVIEW
Lauren Budenholzer, Chin Leng Cheng, Yanjie Li, Mark Hochstrasser
The eukaryotic 26S proteasome is a large multisubunit complex that degrades the majority of proteins in the cell under normal conditions. The 26S proteasome can be divided into two subcomplexes: the 19S regulatory particle and the 20S core particle. Most substrates are first covalently modified by ubiquitin, which then directs them to the proteasome. The function of the regulatory particle is to recognize, unfold, deubiquitylate, and translocate substrates into the core particle, which contains the proteolytic sites of the proteasome...
June 3, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28559891/systematic-optimization-of-protein-secretory-pathways-in-saccharomyces-cerevisiae-to-increase-expression-of-hepatitis-b-small-antigen
#20
Jiayuan Sheng, Hunter Flick, Xueyang Feng
Hepatitis B is a major disease that chronically infects millions of people in the world, especially in developing countries. Currently, one of the effective vaccines to prevent Hepatitis B is the Hepatitis B Small Antigen (HBsAg), which is mainly produced by the recombinant yeast Saccharomyces cerevisiae. In order to bring down the price, which is still too high for people in developing countries to afford, it is important to understand key cellular processes that limit protein expression. In this study, we took advantage of yeast knockout collection (YKO) and screened 194 S...
2017: Frontiers in Microbiology
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