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Author

Reinhild Prange

Other affiliations: Max Planck Society
Bio: Reinhild Prange is an academic researcher from University of Mainz. The author has contributed to research in topics: Hepatitis B virus & Endoplasmic reticulum. The author has an hindex of 26, co-authored 46 publications receiving 6750 citations. Previous affiliations of Reinhild Prange include Max Planck Society.

Papers
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Journal ArticleDOI
Daniel J. Klionsky1, Kotb Abdelmohsen2, Akihisa Abe3, Joynal Abedin4  +2519 moreInstitutions (695)
TL;DR: In this paper, the authors present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macro-autophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes.
Abstract: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure flux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation, it is imperative to target by gene knockout or RNA interference more than one autophagy-related protein. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways implying that not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular assays, we hope to encourage technical innovation in the field.

5,187 citations

Journal ArticleDOI
TL;DR: It is demonstrated that all envelope proteins synthesized in transfected cells or in a cell‐free system adopt more than one transmembrane orientation.
Abstract: The small (S), middle (M) and large (L) envelope proteins of the hepatitis B virus (HBV) are initially synthesized as multispanning membrane proteins of the endoplasmic reticulum membrane We now demonstrate that all envelope proteins synthesized in transfected cells or in a cell-free system adopt more than one transmembrane orientation The L protein disposes its N-terminal preS domain both to the cytoplasmic and the luminal side of the membrane This unusual topology does not depend on interaction with the viral nucleocapsid, but is preserved in secreted empty envelope particles Pulse-chase analysis suggests a novel process of post-translational translocation leading to the non-uniform topology Analysis of L deletion mutants indicates that the block to co-translational translocation can be attributed to a specific sequence within preS, suggesting that translocation of L may be regulated Additional topological heterogeneity is displayed in the S region of the envelope proteins and in the S protein itself, as assayed in a cell-free system S proteins integrated into microsomal membranes exhibit both a luminal and a cytoplasmic orientation of the internal hydrophilic region carrying the major antigenic determinants This may explain the unusual partial glycosylation of the HBV envelope proteins

193 citations

Journal ArticleDOI
TL;DR: It is demonstrated that HBV exploits the MVB machinery with the aid of γ2-adaptin, and the effects of its overexpression in virus-replicating cells are examined, hinting at different export routes used by viral and subviral particles.
Abstract: Hepatitis B virus (HBV) is an enveloped DNA virus that presumably buds at intracellular membranes of infected cells. HBV budding involves two endocytic host proteins, the ubiquitin-interacting adaptor γ2-adaptin and the Nedd4 ubiquitin ligase. Here, we demonstrate that HBV release also requires the cellular machinery that generates internal vesicles of multivesicular bodies (MVBs). In order to perturb the MVB machinery in HBV-replicating liver cells, we used ectopic expression of dominant-negative mutants of different MVB components, like the ESCRT-III complex-forming CHMP proteins and the Vps4 ATPases. Upon coexpression of mutated CHMP3, CHMP4B, or CHMP4C forms, as well as of ATPase-defective Vps4A or Vps4B mutants, HBV assembly and egress were potently blocked. Each of the MVB inhibitors arrested virus particle maturation by entrapping the viral core and large and small envelope proteins in detergent-insoluble membrane structures that closely resembled aberrant endosomal class E compartments. In contrast, HBV subvirus particle release was not affected by MVB inhibitors, hinting at different export routes used by viral and subviral particles. To further define the role γ2-adaptin plays in HBV formation, we examined the effects of its overexpression in virus-replicating cells. Intriguingly, excess γ2-adaptin blocked HBV production in a manner similar to the actions of CHMP and Vps4 mutants. Moreover, overexpressed γ2-adaptin perturbed the endosomal morphology and diminished the budding of a retroviral Gag protein, implying that it may act as a principal inhibitor of the MVB sorting pathway. Together, these results demonstrate that HBV exploits the MVB machinery with the aid of γ2-adaptin.

160 citations

Journal ArticleDOI
TL;DR: It is suggested that different parts of the yeast YPT1 protein are required for the interaction with cellular targets and that these essential parts are conserved in the mammalian ypt1 protein.
Abstract: The protein-coding region of the essential Saccharomyces cerevisiae YPT1 gene coding for a ras-related, guanine-nucleotide-binding protein was exchanged in chromosome VI by the protein-coding segment of either the mouse ypt1 gene or the v-Ki-ras gene, and different chimeric YPT1-v-Ki-ras genes. The mouse ypt1 protein with 71% of identical residues compared with the yeast Ypt1 protein could functionally fully replace its yeast homologue as long as the mouse gene was overexpressed under transcriptional control of the inducible GAL10 promoter. In contrast, neither the viral Ki-ras nor the hybrid proteins were able to substitute for the loss of YPT1 gene function. This study suggests that different parts of the yeast Ypt1 protein are required for the interaction with cellular targets and that these essential parts are conserved in the mammalian ypt1 protein.

129 citations

Journal ArticleDOI
TL;DR: The Saccharomyces cerevisiae YPT1 gene codes for a ras‐like, guanine nucleotide‐binding protein which is essential for cell viability and it was found that as long as one of the cysteines was retained, the protein was fully functional.
Abstract: The Saccharomyces cerevisiae YPT1 gene codes for a ras-like, guanine nucleotide-binding protein which is essential for cell viability. The functional significance of two consecutive cysteines at the very carboxyl-terminal end of this protein and in ypt homologues of other eukaryotic species was examined. YPT1 gene mutations were generated that either led to substitutions by serine or the deletion of one or both C-terminal cysteines. The consequences of the mutations were checked in cells after replacing the wild type with the mutant genes. It was found that as long as one of the cysteines was retained, the protein was fully functional. The YPT1 protein could be labelled with [3H]palmitic acid that appeared to be bound in an ester linkage. The wild-type protein was evenly distributed between soluble and membrane-associated proteins, the palmitoylated form was predominantly in the crude membrane fraction. The mutant protein lacking the C-terminal cysteines was not palmitoylated and was exclusively found in the soluble fraction. The extension by three residues, -Val-Leu-Ser, generating a ras-typical C-terminal end, did not interfere with the mutant YPT1 protein's function although it resulted in a reduced labelling with palmitic acid.

119 citations


Cited by
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Journal ArticleDOI
David E. Gordon, Gwendolyn M. Jang, Mehdi Bouhaddou, Jiewei Xu, Kirsten Obernier, Kris M. White1, Matthew J. O’Meara2, Veronica V. Rezelj3, Jeffrey Z. Guo, Danielle L. Swaney, Tia A. Tummino4, Ruth Hüttenhain, Robyn M. Kaake, Alicia L. Richards, Beril Tutuncuoglu, Helene Foussard, Jyoti Batra, Kelsey M. Haas, Maya Modak, Minkyu Kim, Paige Haas, Benjamin J. Polacco, Hannes Braberg, Jacqueline M. Fabius, Manon Eckhardt, Margaret Soucheray, Melanie J. Bennett, Merve Cakir, Michael McGregor, Qiongyu Li, Bjoern Meyer3, Ferdinand Roesch3, Thomas Vallet3, Alice Mac Kain3, Lisa Miorin1, Elena Moreno1, Zun Zar Chi Naing, Yuan Zhou, Shiming Peng4, Ying Shi, Ziyang Zhang, Wenqi Shen, Ilsa T Kirby, James E. Melnyk, John S. Chorba, Kevin Lou, Shizhong Dai, Inigo Barrio-Hernandez5, Danish Memon5, Claudia Hernandez-Armenta5, Jiankun Lyu4, Christopher J.P. Mathy, Tina Perica4, Kala Bharath Pilla4, Sai J. Ganesan4, Daniel J. Saltzberg4, Rakesh Ramachandran4, Xi Liu4, Sara Brin Rosenthal6, Lorenzo Calviello4, Srivats Venkataramanan4, Jose Liboy-Lugo4, Yizhu Lin4, Xi Ping Huang7, Yongfeng Liu7, Stephanie A. Wankowicz, Markus Bohn4, Maliheh Safari4, Fatima S. Ugur, Cassandra Koh3, Nastaran Sadat Savar3, Quang Dinh Tran3, Djoshkun Shengjuler3, Sabrina J. Fletcher3, Michael C. O’Neal, Yiming Cai, Jason C.J. Chang, David J. Broadhurst, Saker Klippsten, Phillip P. Sharp4, Nicole A. Wenzell4, Duygu Kuzuoğlu-Öztürk4, Hao-Yuan Wang4, Raphael Trenker4, Janet M. Young8, Devin A. Cavero4, Devin A. Cavero9, Joseph Hiatt4, Joseph Hiatt9, Theodore L. Roth, Ujjwal Rathore4, Ujjwal Rathore9, Advait Subramanian4, Julia Noack4, Mathieu Hubert3, Robert M. Stroud4, Alan D. Frankel4, Oren S. Rosenberg, Kliment A. Verba4, David A. Agard4, Melanie Ott, Michael Emerman8, Natalia Jura, Mark von Zastrow, Eric Verdin10, Eric Verdin4, Alan Ashworth4, Olivier Schwartz3, Christophe d'Enfert3, Shaeri Mukherjee4, Matthew P. Jacobson4, Harmit S. Malik8, Danica Galonić Fujimori, Trey Ideker6, Charles S. Craik, Stephen N. Floor4, James S. Fraser4, John D. Gross4, Andrej Sali, Bryan L. Roth7, Davide Ruggero, Jack Taunton4, Tanja Kortemme, Pedro Beltrao5, Marco Vignuzzi3, Adolfo García-Sastre, Kevan M. Shokat, Brian K. Shoichet4, Nevan J. Krogan 
30 Apr 2020-Nature
TL;DR: A human–SARS-CoV-2 protein interaction map highlights cellular processes that are hijacked by the virus and that can be targeted by existing drugs, including inhibitors of mRNA translation and predicted regulators of the sigma receptors.
Abstract: A newly described coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of coronavirus disease 2019 (COVID-19), has infected over 2.3 million people, led to the death of more than 160,000 individuals and caused worldwide social and economic disruption1,2. There are no antiviral drugs with proven clinical efficacy for the treatment of COVID-19, nor are there any vaccines that prevent infection with SARS-CoV-2, and efforts to develop drugs and vaccines are hampered by the limited knowledge of the molecular details of how SARS-CoV-2 infects cells. Here we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins that physically associated with each of the SARS-CoV-2 proteins using affinity-purification mass spectrometry, identifying 332 high-confidence protein–protein interactions between SARS-CoV-2 and human proteins. Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (of which, 29 drugs are approved by the US Food and Drug Administration, 12 are in clinical trials and 28 are preclinical compounds). We screened a subset of these in multiple viral assays and found two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the sigma-1 and sigma-2 receptors. Further studies of these host-factor-targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19. A human–SARS-CoV-2 protein interaction map highlights cellular processes that are hijacked by the virus and that can be targeted by existing drugs, including inhibitors of mRNA translation and predicted regulators of the sigma receptors.

3,319 citations

Journal ArticleDOI
Lorenzo Galluzzi1, Lorenzo Galluzzi2, Ilio Vitale3, Stuart A. Aaronson4  +183 moreInstitutions (111)
TL;DR: The Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives.
Abstract: Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field.

3,301 citations

Journal ArticleDOI
TL;DR: This work has shown that for specific tasks the Hsp70 cycle is coupled to the action of other chaperones, such as Hsp90 and Hsp100, and this ATPase cycle is controlled by co-chaperones of the family of J-domain proteins, which target H Sp70s to their substrates, and by nucleotide exchange factors, which determine the lifetime of the HSp70-substrate complex.
Abstract: Hsp70 proteins are central components of the cellular network of molecular chaperones and folding catalysts. They assist a large variety of protein folding processes in the cell by transient association of their substrate binding domain with short hydrophobic peptide segments within their substrate proteins. The substrate binding and release cycle is driven by the switching of Hsp70 between the low-affinity ATP bound state and the high-affinity ADP bound state. Thus, ATP binding and hydrolysis are essential in vitro and in vivo for the chaperone activity of Hsp70 proteins. This ATPase cycle is controlled by co-chaperones of the family of J-domain proteins, which target Hsp70s to their substrates, and by nucleotide exchange factors, which determine the lifetime of the Hsp70-substrate complex. Additional co-chaperones fine-tune this chaperone cycle. For specific tasks the Hsp70 cycle is coupled to the action of other chaperones, such as Hsp90 and Hsp100.

2,564 citations

Journal ArticleDOI
TL;DR: In this review, functions of small G proteins and their modes of activation and action are described.
Abstract: Small GTP-binding proteins (G proteins) exist in eukaryotes from yeast to human and constitute a superfamily consisting of more than 100 members. This superfamily is structurally classified into at least five families: the Ras, Rho, Rab, Sar1/Arf, and Ran families. They regulate a wide variety of cell functions as biological timers (biotimers) that initiate and terminate specific cell functions and determine the periods of time for the continuation of the specific cell functions. They furthermore play key roles in not only temporal but also spatial determination of specific cell functions. The Ras family regulates gene expression, the Rho family regulates cytoskeletal reorganization and gene expression, the Rab and Sar1/Arf families regulate vesicle trafficking, and the Ran family regulates nucleocytoplasmic transport and microtubule organization. Many upstream regulators and downstream effectors of small G proteins have been isolated, and their modes of activation and action have gradually been elucidated. Cascades and cross-talks of small G proteins have also been clarified. In this review, functions of small G proteins and their modes of activation and action are described.

2,520 citations

Journal ArticleDOI
08 Nov 1990-Nature
TL;DR: A molecular switch is a molecular switch whose "on" and "off" states are triggered by binding and hydrolysis of GTP as discussed by the authors. But the mechanism in myriad versions of the switch can be traced back to a single primordial protein.
Abstract: Proteins that bind and hydrolyse GTP are being discovered at a rapidly increasing rate. Each of these many GTPases acts as a molecular switch whose 'on' and 'off' states are triggered by binding and hydrolysis of GTP. Conserved structure and mechanism in myriad versions of the switch--in bacteria, yeast, flies and vertebrates--suggest that all derive from a single primordial protein, repeatedly modified in the course of evolution to perform a dazzling variety of functions.

2,261 citations