Read by QxMD icon Read


Oznur Bayraktar, Ozlem Oral, Nur Mehpare Kocaturk, Yunus Akkoc, Karin Eberhart, Ali Kosar, Devrim Gozuacik
The ubiquitin-proteasome system (UPS) degrades soluble proteins and small aggregates, whereas macroautophagy (autophagy herein) eliminates larger protein aggregates, tangles and even whole organelles in a lysosome-dependent manner. VCP/p97 was implicated in both pathways. VCP/p97 mutations cause a rare multisystem disease called IBMPFD (Inclusion Body Myopathy with Paget's Disease and Frontotemporal Dementia). Here, we studied the role IBMPFD-related mutants of VCP/p97 in autophagy. In contrast with the wild-type VCP/p97 protein or R155C or R191Q mutants, the P137L mutant was aggregate-prone...
2016: PloS One
Chrisovalantis Papadopoulos, Philipp Kirchner, Monika Bug, Daniel Grum, Lisa Koerver, Nina Schulze, Robert Poehler, Alina Dressler, Sven Fengler, Khalid Arhzaouy, Vanda Lux, Michael Ehrmann, Conrad C Weihl, Hemmo Meyer
Rupture of endosomes and lysosomes is a major cellular stress condition leading to cell death and degeneration. Here, we identified an essential role for the ubiquitin-directed AAA-ATPase, p97, in the clearance of damaged lysosomes by autophagy. Upon damage, p97 translocates to lysosomes and there cooperates with a distinct set of cofactors including UBXD1, PLAA, and the deubiquitinating enzyme YOD1, which we term ELDR components for Endo-Lysosomal Damage Response. Together, they act downstream of K63-linked ubiquitination and p62 recruitment, and selectively remove K48-linked ubiquitin conjugates from a subpopulation of damaged lysosomes to promote autophagosome formation...
October 17, 2016: EMBO Journal
Prasad Kottayil Padmanabhan, Ouafa Zghidi-Abouzid, Mukesh Samant, Carole Dumas, Bruno Guedes Aguiar, Jerome Estaquier, Barbara Papadopoulou
DDX3 is a highly conserved member of ATP-dependent DEAD-box RNA helicases with multiple functions in RNA metabolism and cellular signaling. Here, we describe a novel function for DDX3 in regulating the mitochondrial stress response in the parasitic protozoan Leishmania. We show that genetic inactivation of DDX3 leads to the accumulation of mitochondrial reactive oxygen species (ROS) associated with a defect in hydrogen peroxide detoxification. Upon stress, ROS production is greatly enhanced, causing mitochondrial membrane potential loss, mitochondrial fragmentation, and cell death...
October 13, 2016: Cell Death & Disease
Prabhakar Bastola, Lisa Neums, Frank J Schoenen, Jeremy Chien
Valosin-containing protein (VCP) or p97, a member of AAA-ATPase protein family, has been associated with various cellular functions including endoplasmic reticulum-associated degradation (ERAD), Golgi membrane reassembly, autophagy, DNA repair, and cell division. Recent studies identified VCP and ubiquitin proteasome system (UPS) as synthetic lethal targets in ovarian cancer. Here, we describe the preclinical activity of VCP inhibitors in ovarian cancer. Results from our studies suggest that quinazoline-based VCP inhibitors initiate G1 cell cycle arrest, attenuate cap-dependent translation and induce programmed cell death via the intrinsic and the extrinsic modes of apoptosis...
September 28, 2016: Molecular Oncology
Rui Ding, Ting Zhang, Jiashu Xie, Jessica Williams, Yihong Ye, Liqiang Chen
Inhibition of p97 (also known as valosin-containing protein (VCP)), has been validated as a promising strategy for cancer therapy. Eeyarestatin I (EerI) blocks p97 through a novel mechanism of action and has favorable anti-cancer activities against cultured cancer cells. However, its poor aqueous solubility severely limits its in vivo applications. To circumvent this problem, we have identified EerI derivatives that possess improved aqueous solubility by introducing a single solubilizing group. These modified compounds preserved endoplasmic reticulum (ER) stress-inducing and antiproliferative activities as well as generally good in vitro metabolic properties, suggesting that these EerI derivatives could serve as candidates for further optimization...
September 29, 2016: Bioorganic & Medicinal Chemistry Letters
Hervé Bègue, Sylvain Jeandroz, Cécile Blanchard, David Wendehenne, Claire Rosnoblet
BACKGROUND: The chaperone-like p97 is a member of the AAA+ ATPase enzyme family that contributes to numerous cellular activities. P97 has been broadly studied in mammals (VCP/p97) and yeasts (CDC48: Cell Division Cycle 48/p97) and numerous investigations highlighted that this protein is post-translationally regulated, is structured in homohexamer and interacts with partners and cofactors that direct it to distinct cellular signalization pathway including protein quality control and degradation, cell cycle regulation, genome stability, vesicular trafficking, autophagy and immunity...
October 4, 2016: Biochimica et Biophysica Acta
Johannes van den Boom, Markus Wolf, Lena Weimann, Nina Schulze, Fanghua Li, Farnusch Kaschani, Anne Riemer, Christian Zierhut, Markus Kaiser, George Iliakis, Hironori Funabiki, Hemmo Meyer
During DNA double-strand break (DSB) repair, the ring-shaped Ku70/80 complex becomes trapped on DNA and needs to be actively extracted, but it has remained unclear what provides the required energy. By means of reconstitution of DSB repair on beads, we demonstrate here that DNA-locked Ku rings are released by the AAA-ATPase p97. To achieve this, p97 requires ATP hydrolysis, cooperates with the Ufd1-Npl4 ubiquitin-adaptor complex, and specifically targets Ku80 that is modified by K48-linked ubiquitin chains...
October 6, 2016: Molecular Cell
Qianzheng Zhu, Altaf A Wani
Nucleotide excision repair (NER) eliminates a broad variety of helix-distorting DNA lesions that can otherwise cause genomic instability. NER comprises two distinct sub-pathways: global genomic NER (GG-NER) operating throughout the genome, and transcription-coupled NER (TC-NER) preferentially removing DNA lesions from transcribing DNA strands of transcriptionally active genes. Several NER factors undergo post-translational modifications, including ubiquitination, occurring swiftly and reversibly at DNA lesion sites...
October 1, 2016: Photochemistry and Photobiology
George Fullbright, Halley B Rycenga, Jordon D Gruber, David T Long
Inter-strand crosslinks (ICLs) are extremely toxic DNA lesions that create an impassable roadblock to DNA replication. When a replication fork collides with an ICL, it triggers a damage response that promotes multiple DNA processing events required to excise the crosslink from chromatin and resolve the stalled replication fork. One of the first steps in this process involves displacement of the CMG replicative helicase (comprised of Cdc45, MCM2-7, and GINS), which obstructs the underlying crosslink. Here we report that the p97/Cdc48/VCP segregase plays a critical role in ICL repair by unloading the CMG complex from chromatin...
September 19, 2016: Molecular and Cellular Biology
Pratikkumar Harsukhbhai Vekaria, Trisha Home, Scott Weir, Frank J Schoenen, Rekha Rao
Cancer cells are addicted to numerous non-oncogenic traits that enable them to thrive. Proteotoxic stress is one such non-oncogenic trait that is experienced by all tumor cells owing to increased genomic abnormalities and the resulting synthesis and accumulation of non-stoichiometric amounts of cellular proteins. This imbalance in the amounts of proteins ultimately culminates in proteotoxic stress. p97, or valosin-containing protein (VCP), is an ATPase whose function is essential to restore protein homeostasis in the cells...
2016: Frontiers in Oncology
Andrea Polo, Stefano Guariniello, Giovanni Colonna, Gennaro Ciliberto, Susan Costantini
Human SELK is a small trans-membrane selenoprotein characterized by a single trans-membrane helix, while the N-terminal region protrudes into the lumen and the long C-terminal domain into the cytoplasm. SELK is over-expressed in some cancers, like hepatocellular carcinoma; however its precise role in cancer development is presently unknown. SELK is involved in promoting the calcium flux, catalyzing palmitoylation reactions and protein degradation in the endoplasmic reticulum (ER). Therefore, this protein should bind many different proteins like p97/VCP in the supramolecular complex involved in the ER degradation pathway...
October 20, 2016: Molecular BioSystems
Kyla Walworth, Manish Bodas, Ryan John Campbell, Doug Swanson, Ajit Sharma, Neeraj Vij
Elevated valosin containing protein (VCP/p97) levels promote the progression of non-small cell lung carcinoma (NSCLC). Although many VCP inhibitors are available, most of these therapeutic compounds have low specificity for targeted tumor cell delivery. Hence, the primary aim of this study was to evaluate the in vitro efficacy of dendrimer-encapsulated potent VCP-inhibitor drug in controlling non-small cell lung carcinoma (NSCLC) progression. The VCP inhibitor(s) (either in their pure form or encapsulated in generation-4 PAMAM-dendrimer with hydroxyl surface) were tested for their in vitro efficacy in modulating H1299 (NSCLC cells) proliferation, migration, invasion, apoptosis and cell cycle progression...
2016: PloS One
Jia Jia Lim, Youngjin Lee, Tue Tu Ly, Jung Youn Kang, Jung-Gyu Lee, Jun Yop An, Hyung-Seop Youn, Kyoung Ryoung Park, Tae Gyun Kim, Jin Kuk Yang, Youngsoo Jun, Soo Hyun Eom
RHBDL4 is an active rhomboid that specifically recognizes and cleaves atypical, positively charged transmembrane endoplasmic reticulum-associated degradation (ERAD) substrates. Interaction of valosin-containing protein (p97/VCP) and RHBDL4 is crucial to retrotranslocate polyubiquitinated substrates for ERAD pathway. Here, we report the first complex structure of VCP-binding motif (VBM) with p97 N-terminal domain (p97N) at 1.88 Å resolution. Consistent with p97 adaptor proteins including p47-ubiquitin regulatory X (UBX), gp78-VCP-interacting motif (VIM), OTU1-UBX-like element, and FAF1-UBX, RHBDL4 VBM also binds at the interface between the two lobes of p97N...
September 15, 2016: Biochemical Journal
Liang Xue, Emily E Blythe, Elyse C Freiberger, Jennifer L Mamrosh, Alexander S Hebert, Justin M Reitsma, Sonja Hess, Joshua J Coon, Raymond J Deshaies
Protein quality control (PQC) plays an important role in stemming neurodegenerative diseases and is essential for the growth of some cancers. Valosin-containing protein (VCP)/p97 plays a pivotal role in multiple PQC pathways by interacting with numerous adaptors that link VCP to specific PQC pathways and substrates and influence the post-translational modification state of substrates. However, our poor understanding of the specificity and architecture of the adaptors, and the dynamic properties of their interactions with VCP hinders our understanding of fundamental features of PQC and how modulation of VCP activity can best be exploited therapeutically...
September 2016: Molecular & Cellular Proteomics: MCP
Vijayendra Dasari, Sweera Rehan, Siok-Keen Tey, Mark J Smyth, Corey Smith, Rajiv Khanna
Cross-presentation of exogenous protein antigens by B cells through the MHC class I pathway in lymphoid malignancies and transplant setting has been recognized as an important mediator of immune pathogenesis and T cell-mediated immune regulation. However, the precise mechanism of cross-presentation of exogenous antigens in B cells has remained unresolved. Here we have delineated a novel pathway for cross-presentation in B cells which involves synergistic cooperation of the proteasome and autophagy. After endocytosis, protein antigen is processed through an autophagy and proteasome-dependent pathway and CD8(+) T-cell epitopes are loaded onto MHC class-I molecules within the autophagolysomal compartment rather than the conventional secretory pathway which requires transporters associated with antigen processing (TAP)-dependent transport...
June 14, 2016: Immunology and Cell Biology
Stacie L Bulfer, Tsui-Fen Chou, Michelle R Arkin
The AAA+ ATPase p97/VCP adopts at least three conformations that depend on the binding of ADP and ATP and alter the orientation of the N-terminal protein-protein interaction (PPI) domain into "up" and "down" conformations. Point mutations that cause multisystem proteinopathy 1 (MSP1) are found at the interface of the N domain and D1-ATPase domain and potentially alter the conformational preferences of p97. Additionally, binding of "adaptor" proteins to the N-domain regulates p97's catalytic activity. We propose that p97/adaptor PPIs are coupled to p97 conformational states...
August 19, 2016: ACS Chemical Biology
Tao Wang, Wangchao Xu, Meiling Qin, Yi Yang, Puhua Bao, Fuxiao Shen, Zhenlin Zhang, Jin Xu
Valosin-containing protein/p97(VCP) is a hexameric ATPase vital to protein degradation during endoplasmic reticulum stress. It regulates diverse cellular functions including autophagy, chromatin remodeling, and DNA repair. In addition, mutations in VCP cause inclusion body myopathy, Paget disease of the bone, and frontotemporal dementia (IBMPFD), as well as amyotrophic lateral sclerosis. Nevertheless, how the VCP activities were regulated and how the pathogenic mutations affect the function of VCP during stress are not unclear...
July 1, 2016: Journal of Biological Chemistry
Frédéric Ebstein, Martin Keller, Annette Paschen, Peter Walden, Michael Seeger, Elke Bürger, Elke Krüger, Dirk Schadendorf, Peter-M Kloetzel, Ulrike Seifert
Efficient processing of target antigens by the ubiquitin-proteasome-system (UPS) is essential for treatment of cancers by T cell therapies. However, immune escape due to altered expression of IFN-γ-inducible components of the antigen presentation machinery and consequent inefficient processing of HLA-dependent tumor epitopes can be one important reason for failure of such therapies. Here, we show that short-term co-culture of Melan-A/MART-1 tumor antigen-expressing melanoma cells with Melan-A/MART-126-35-specific cytotoxic T lymphocytes (CTL) led to resistance against CTL-induced lysis because of impaired Melan-A/MART-126-35 epitope processing...
2016: Scientific Reports
Ramesh Rijal, Khalid Arhzaouy, Karl-Heinz Strucksberg, Megan Cross, Andreas Hofmann, Rolf Schröder, Christoph S Clemen, Ludwig Eichinger
p97 (VCP) is a homo-hexameric triple-A ATPase that exerts a plethora of cellular processes. Heterozygous missense mutations of p97 cause at least five human neurodegenerative disorders. However, the specific molecular consequences of p97 mutations are hitherto widely unknown. Our in silico structural models of human and Dictyostelium p97 showed that the disease-causing human R93C, R155H, and R155C as well as Dictyostelium R154C, E219K, R154C/E219K p97 mutations constitute variations in surface-exposed locations...
June 2016: European Journal of Cell Biology
Nam-Gu Her, Julia I Toth, Chen-Ting Ma, Yang Wei, Khatereh Motamedchaboki, Eduard Sergienko, Matthew D Petroski
The AAA ATPase p97/VCP regulates protein homeostasis using a diverse repertoire of cofactors to fulfill its biological functions. Here we use the allosteric p97 inhibitor NMS-873 to analyze its effects on enzyme composition and the ability of cells to adapt to its cytotoxicity. We found that p97 inhibition changes steady state cofactor-p97 composition, leading to the enrichment of a subset of its cofactors and polyubiquitin bound to p97. We isolated cells specifically insensitive to NMS-873 and identified a new mutation (A530T) in p97...
April 21, 2016: Cell Chemical Biology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"