Biochemistry, Biophysics, and Structural Biology Commons^™

Autoimmunity In Picornavirus Infections, Chandirasegara Massilamany, Andreas Koenig, Jay Reddy, Sally Huber, Iwona Buskiewicz

School of Veterinary and Biomedical Sciences: Faculty Publications

Enteroviruses are small, non-enveloped, positive-sense singlestrand RNA viruses, and are ubiquitously found throughout the world. These viruses usually cause asymptomatic or mild febrile illnesses, but have a propensity to induce severe diseases including type 1 diabetes and pancreatitis, paralysis and neuroinflammatory disease, myocarditis, or hepatitis. This pathogenicity may result from induction of autoimmunity to organ-specific antigens. While enterovirus-triggered autoimmunity can arise from multiple mechanisms including antigenic mimicry and release of sequestered antigens, the recent demonstration of T cells expressing dual T cell receptors arising as a natural consequence of Theiler’s virus infection is the first demonstration of this autoimmune mechanism.

Genome-Wide Search For Host Association Factors During Ovine Progressive Pneumonia Virus Infection, Jesse Thompson, Fangrui Ma, Meghan Quinn, Shi-Hua Xiang

School of Veterinary and Biomedical Sciences: Faculty Publications

Ovine progressive pneumonia virus (OPPV) is an important virus that causes serious diseases in sheep and goats with a prevalence of 36% in the USA. Although OPPV was discovered more than half of a century ago, little is known about the infection and pathogenesis of this virus. In this report, we used RNA-seq technology to conduct a genome-wide probe for cellular factors that are associated with OPPV infection. A total of approximately 22,000 goat host genes were detected of which 657 were found to have been significantly up-regulated and 889 down-regulated at 12 hours post-infection. In addition to previously known …

Guidelines For The Use And Interpretation Of Assays For Monitoring Autophagy (3rd Edition), Daniel J. Klionsky, Rodrigo Franco, More Than 2,000 Co-Authors

School of Veterinary and Biomedical Sciences: Faculty Publications

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 …

From Crystal Structure Of Α-Conotoxin Gic In Complex With Ac-Achbp To Molecular Determinants Of Its High Selectivity For Α3Β2 Nachr, Bo Lin, Manyu Xu, Xiaopeng Zhu, Yong Wu, Xi Liu, Dongting Zhangsun, Yuanyan Hu, Shi-Hua Xiang, Igor E. Kasheverov, Victor I. Tsetlin, Xinquan Wang, Sulan Luo

School of Veterinary and Biomedical Sciences: Faculty Publications

Acetylcholine binding proteins (AChBPs) are unique spatial homologs of the ligand-binding domains of nicotinic acetylcholine receptors (nAChRs), and they reproduce some pharmacological properties of nAChRs. X-ray crystal structures of AСhBP in complex with α-conotoxins provide important insights into the interactions of α-conotoxins with distinct nAChR subtypes. Although considerable efforts have been made to understand why α-conotoxin GIC is strongly selective for α3β2 nAChR, this question has not yet been solved. Here we present the structure of α-conotoxin GIC in complex with Aplysia californica AChBP (Ac-AChBP) at a resolution of 2.1 Å. Based on this co-crystal structure complemented with molecular docking …

From Crystal Structure Of Α-Conotoxin Gic In Complex With Ac-Achbp To Molecular Determinants Of Its High Selectivity For Α3Β2 Nachr, Bo Lin, Manyu Xu, Xiaopeng Zhu, Yong Wu, Xi Liu, Dongting Zhangsun, Yuanyan Hu, Shi-Hua Xiang, Igor E. Kasheverov, Victor I. Tsetlin, Xianquan Wang, Sulan Luo

School of Veterinary and Biomedical Sciences: Faculty Publications

Acetylcholine binding proteins (AChBPs) are unique spatial homologs of the ligand-binding domains of nicotinic acetylcholine receptors (nAChRs), and they reproduce some pharmacological properties of nAChRs. X-ray crystal structures of AСhBP in complex with α-conotoxins provide important insights into the interactions of α-conotoxins with distinct nAChR subtypes. Although considerable efforts have been made to understand why α-conotoxin GIC is strongly selective for α3β2 nAChR, this question has not yet been solved. Here we present the structure of α-conotoxin GIC in complex with Aplysia californica AChBP (Ac-AChBP) at a resolution of 2.1 Å. Based on this co-crystal structure complemented with molecular docking …

A Synthetic Porcine Reproductive And Respiratory Syndrome Unprecedented Levels Of Heterologous Protection, Hiep Vu, Fangrui Ma, William W. Laegreid, Asit K. Pattnaik, David Steffen, Alan R. Doster, Fernando A. Osorio

School of Veterinary and Biomedical Sciences: Faculty Publications

Current vaccines do not provide sufficient levels of protection against divergent porcine reproductive and respiratory syndrome virus (PRRSV) strains circulating in the field, mainly due to the substantial variation of the viral genome. We describe here a novel approach to generate a PRRSV vaccine candidate that could confer unprecedented levels of heterologous protection against divergent PRRSV isolates. Using a set of 59 non-redundant, full genome sequences of type-2 PRRSV, a consensus genome (designated as PRRSV-CON) was these 59 PRRSV full genome sequences, followed by selecting the most common nucleotide found at each position of the alignment. Next, the synthetic PRRSV-CON …

Overview Of Rhabdo- And Filoviruses, Asit K. Pattnaik, Michael A. Whitt

School of Veterinary and Biomedical Sciences: Faculty Publications

Enveloped viruses with a negative-sense, single-stranded monopartite RNA genome have been classified into the order Mononegavirales. Five families of viruses that constitute the order are: Rhabdoviridae, Filoviridae, Paramyxoviridae, Bornaviridae and Nyamiviridae. Members of these families possess a helical nucleocapsid core containing the viral genome and a host-derived lipid envelope containing viral proteins. This introductory chapter provides a brief overview of the Rhabdoviridae and the Filoviridae, the two families of viruses that are the subject of this book. Many members of these two families are highly significant human and animal pathogens. The rationale and goal of the book is to …

On And Off Retinal Ganglion Cells Differentially Regulate Serotonergic And Gabaergic Activity In The Dorsal Raphe Nucleus, Ting Zhang, Lu Huang, Li Zhang, Minjie Tan, Mingliang Pu, Gary E. Pickard, Kwok -Fai So, Chaoran Ren

School of Veterinary and Biomedical Sciences: Faculty Publications

The dorsal raphe nucleus (DRN), the major source of serotonergic input to the forebrain, receives excitatory input from the retina that can modulate serotonin levels and depressive-like behavior. In the Mongolian gerbil, retinal ganglion cells (RGCs) with alpha-like morphological and Y-like physiological properties innervate the DRN with ON DRN-projecting RGCs out numbering OFF DRN-projecting RGCs. The DRN neurons targeted by ON and OFF RGCs are unknown. To explore retino-raphe anatomical organization, retinal afferents labeled with Cholera toxin B were examined for association with the postsynaptic protein PSD-95. Synaptic associations between retinal afferents and DRN serotonergic and GABAergic neurons were observed. …

Whole Genomic Sequence Analysis Of Bacillus Infantis: Defining The Genetic Blueprint Of Strain Nrrl B-14911, An Emerging Cardiopathogenic Microbe, Chandirasegara Massilamany, Akram Mohammed, John Dustin Loy, Tanya Purvis, Bharathi Krishnan, Rakesh H. Basavalingappa, Christy M. Kelley, Chittibabu Guda, Raúl G. Barletta, Etsuko N. Moriyama, Timothy P.L. Smith, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: We recently reported the identification of Bacillus sp. NRRL B-14911 that induces heart autoimmunity by generating cardiac-reactive T cells through molecular mimicry. This marine bacterium was originally isolated from the Gulf of Mexico, but no associations with human diseases were reported. Therefore, to characterize its biological and medical significance, we sought to determine and analyze the complete genome sequence of Bacillus sp. NRRL B-14911.

Results: Based on the phylogenetic analysis of 16S ribosomal RNA (rRNA) genes, sequence analysis of the 16S-23S rDNA intergenic transcribed spacers, phenotypic microarray, and matrix-assisted laser desorption ionization time-offlight mass spectrometry, we propose that this …

Host Cell Functions In Vesicular Stomatitis Virus Replication, Phat X. Dinh, Anshuman Das, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

Vesicular stomatitis virus (VSV), the prototypic rhabdovirus, has been used as an excellent paradigm for understanding the mechanisms of virus replication, pathogenesis, host response to virus infection and also for myriads of studies on cellular and molecular biology. Biochemical studies as well as high-throughput genomics, proteomics, and chemical approaches have revealed a plethora of cellular factors and pathways that regulate replication of VSV. These factors include those that support virus replication and also those that restrict its replication. This chapter discusses the role(s) of many of these host cell factors and pathways involved in VSV replication. Although mechanistic understanding of …

Erratum To: Association Of Autophagy In The Cell Death Mediated By Dihydrotestosterone In Autoreactive T Cells Independent Of Antigenic Stimulation, Ting Jia, Anandhan Annadurai, Chandirasegara Massilamany, Rajkumar A. Rajasekaran, Rodrigo Franco, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

No abstract provided.

New Tools To Convert Bacterial Artificial Chromosomes To A Self-Excising Design And Their Application To A Herpes Simplex Virus Type 1 Infectious Clone, Alexsia L. Richards, Patricia J. Sollars, Gregory A. Smith

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: Infectious clones are fundamental tools for the study of many viruses, allowing for efficient mutagenesis and reproducible production of genetically-defined strains. For the large dsDNA genomes of the herpesviridae, bacterial artificial chromosomes have become the cloning vector of choice due to their capacity to house full-length herpesvirus genomes as single contiguous inserts. Furthermore, while maintained as plasmids in Escherichia coli, the clones can be mutated using robust prokaryotic recombination systems. An important consideration in the design of these clones is the means by which the vector backbone is removed from the virus genome upon delivery into mammalian cells. …

Resolving Bovine Viral Diarrhea Virus Subtypes From Persistently Infected U.S. Beef Calves With Complete Genome Sequence, Aspen M. Workman, Michael P. Heaton, Gregory P. Harhay, Timothy P.L. Smith, Dale M. Grotelueschen, David Sjeklocha, Bruce Brodersen, Jessica L. Petersen, Carol G. Chitko-Mckown

School of Veterinary and Biomedical Sciences: Faculty Publications

Bovine viral diarrhea virus (BVDV) is classified into 2 genotypes, BVDV-1 and BVDV-2, each of which contains distinct subtypes with genetic and antigenic variation. To effectively control BVDV by vaccination, it is important to know which subtypes of the virus are circulating and how their prevalence is changing over time. Accordingly, the purpose of our study was to estimate the current prevalence and diversity of BVDV subtypes from persistently infected (PI) beef calves in the central United States. Phylogenetic analysis of the 5′-UTR (5′ untranslated region) for 119 virus strains revealed that a majority (82%) belonged to genotype 1b, and …

Maporal Hantavirus Causes Mild Pathology In Deer Mice (Peromyscus Maniculatus), Amanda Mcguire, Kaitlyn Miedema, Joseph R. Fauver, Amber Rico, Tawfik Aboellail, Sandra L. Quackenbush, Ann Hawkinson, Tony Schountz

School of Veterinary and Biomedical Sciences: Faculty Publications

Rodent-borne hantaviruses can cause two human diseases with many pathological similarities: hantavirus cardiopulmonary syndrome (HCPS) in the western hemisphere and hemorrhagic fever with renal syndrome in the eastern hemisphere. Each virus is hosted by specific reservoir species without conspicuous disease. HCPS-causing hantaviruses require animal biosafety level-4 (ABSL-4) containment, which substantially limits experimental research of interactions between the viruses and their reservoir hosts. Maporal virus (MAPV) is a South American hantavirus not known to cause disease in humans, thus it can be manipulated under ABSL-3 conditions. The aim of this study was to develop an ABSL-3 hantavirus infection model using the …

The Mechanistic Basis Of Hemoglobin Adaptation In The High-Flying Barheaded Goose: Insights From Ancestral Protein Resurrection, Chandrasekhar Natarajan, Amit Kumar, Hideaki Moriyama, Roy E. Weber, Angela Fago, Jay F. Storz

School of Veterinary and Biomedical Sciences: Faculty Publications

The bar-headed goose (‘BHG’, Anser indicus) is renowned for its trans-Himalayan migratory flights, and the elevated hemoglobin (Hb)-O2 affinity of this species is thought to make a key contribution to its capacity for powered flight at elevations of ~9000 m. Here we revisit the molecular basis of this text-book example of biochemical adaptation. Previous hypotheses about the molecular basis of the evolved increase in Hb-O2 affinity were tested by engineering BHGspecific mutations into recombinant human Hb. This approach can provide important insights, but one problem with such ‘horizontal’ comparisons – swapping residues between proteins of contemporary species – is that …

Localization Of Cd8 T Cell Epitope Within Cardiac Myosin Heavy Chain-Α334-352 That Induces Autoimmune Myocarditis In A/J Mice, Chandirasegara Massilamany, Arunakumar Gangaplara, Rakesh H. Basavalingappa, Rajkumar A. Rajasekaran, Vahid Khalilzad-Sharghi, Zhongji Han, Shadi F. Othman, David Steffen, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

Background—Cardiac myosin heavy chain-α (Myhc), an intracellular protein expressed in the cardiomyocytes, has been identified as a major autoantigen in cardiac autoimmunity. In our studies with Myhc_334-352-induced experimental autoimmune myocarditis in A/J mice (H-2a), we discovered that Myhc_334-352, supposedly a CD4 T cell epitope, also induced antigen-specific CD8 T cells that transfer disease to naïve animals.

Methods and Results—In our efforts to identify the CD8 T cell determinants, we localized Myhc_338-348 within the full length-Myhc_334-352, leading to four key findings. (1) By acting as a dual epitope, Myhc_338-348 induces both …

Visualizing Herpesvirus Procapsids In Living Cells, Oana Maier, Patricia J. Sollars, Gary E. Pickard, Gregory A. Smith

School of Veterinary and Biomedical Sciences: Faculty Publications

A complete understanding of herpesvirus morphogenesis requires studies of capsid assembly dynamics in living cells. Although fluorescent tags fused to the VP26 and pUL25 capsid proteins are available, neither of these components is present on the initial capsid assembly, the procapsid. To make procapsids accessible to live-cell imaging, we made a series of recombinant pseudorabies viruses that encoded green fluorescent protein (GFP) fused in frame to the internal capsid scaffold and maturation protease. One recombinant, a GFP-VP24 fusion, maintained wild-type propagation kinetics in vitro and approximated wild-type virulence in vivo. The fusion also proved to be well tolerated in …

Note On Ehrlichia Chaffeensis, Ehrlichia Ewingii, And “Borrelia Lonestari” Infection In Lone Star Ticks (Acari: Ixodidae), Nebraska, Usa, Amanda Maegli, J. Dustin Loy, Roberto Cortinas

School of Veterinary and Biomedical Sciences: Faculty Publications

The lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae), is established in southeastern Nebraska, yet the prevalence of tick-associated microorganisms is not known. An initial PCR-based analysis for Ehrlichia chaffeensis, Ehrlichia ewingii, and Borrelia infection in host-seeking adult ticks collected in southeast Nebraska was conducted. A total of 251 adult ticks collected in six sites in southeast Nebraska were tested. E. chaffeensis, E. ewingii, and Borrelia spp. were present, and the prevalence of each was approximately 1.6%. This study demonstrates that Ehrlichia spp. are present in Nebraska lone star tick populations.

Expression And Distribution Of Thiol-Regulating Enzyme Glutaredoxin 2 (Grx2) In Porcine Ocular Tissues, Bijaya Upadhyaya, Xiaoli Tian, Hongli Wu, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

Glutaredoxin2 (Grx2) is a mitochondrial isozyme of the cytosolic glutaredoxin1 (thioltransferase or TTase). Both belong to the large oxidoreductase family and play an important role in maintaining thiol/disulfide redox homeostasis in the cells. Grx2 is recently found in the lens where its activities of disulfide reductase and peroxidase, similar to TTase, can protect the lens against oxidative stress. Since other eye tissues are also highly sensitive to oxidative stress, and TTase’s distribution in the eye is known, we focused on this study by investigating the Grx2 distribution in the ocular tissues in comparison to the lens. Fresh porcine eyes were …

Analysis Of Mycobacterium Avium Subsp. Paratuberculosis Mutant Libraries Reveals Loci-Dependent Transposition Biases And Strategies For Novel Mutant Discovery, Govardhan Rathnaiah, John Bannantine, Darrell O. Bayles, Denise K. Zinniel, Judith R. Stabel, Yrjö T. Gröhn, Raúl G. Barletta

School of Veterinary and Biomedical Sciences: Faculty Publications

Mycobacterium avium subsp. paratuberculosis (MAP), the aetiological agent of Johne’s disease, is one of the most important bacterial pathogens in ruminants. A thorough understanding of MAP pathogenesis is needed to develop new vaccines and diagnostic tests. The generation of comprehensive random transposon mutant libraries is a fundamental genetic technology to determine the role of genes in physiology and pathogenesis. In this study, whole MAP genome analysis compared the insertion sites for the mycobacterial transposon Tn5367 derived from the Mycobacterium smegmatis insertion sequence IS1096 and the mariner transposon MycoMarT7 carrying the Himar1 transposase. We determined that only MycoMarT7 provides …

Mosquito Host Choices On Livestock Amplifiers Of Rift Valley Fever Virus In Kenya, David P. Tchouassi, Robinson O. Okiro, Rosemary Sang, Lee W. Cohnstaedt, D. Scott Mcvey, Baldwyn Torto

School of Veterinary and Biomedical Sciences: Faculty Publications

Background: Animal hosts may vary in their attraction and acceptability as components of the host location process for assessing preference, and biting rates of vectors and risk of exposure to pathogens. However, these parameters remain poorly understood for mosquito vectors of the Rift Valley fever (RVF), an arboviral disease, and for a community of mosquitoes.

Methods: Using three known livestock amplifiers of RVF virus including sheep, goat and cattle as bait in enclosure traps, we investigated the host-feeding patterns for a community of mosquitoes in Naivasha, an endemic area of Rift Valley fever (RVF), in a longitudinal study for six …

Astrogliosis In A Dish: Substrate Stiffness Induces Astrogliosis In Primary Rat Astrocytes, Christina L. Wilson, Stephen L. Hayward, Srivatsan Kidambi

Department of Chemical and Biomolecular Engineering: Faculty Publications

Astrogliosis due to brain injury or disease can lead to varying molecular and morphological changes in astrocytes. Magnetic resonance elastography and ultrasound have demonstrated that brain stiffness varies with age and disease state. However, there is a lack in understanding the role of varied stiffness on the progression of astrogliosis highlighting a critical need to engineer in vitro models that mimic disease stages. Such models need to incorporate the dynamic changes in the brain microenvironment including the stiffness changes. In this study we developed a polydimethyl siloxane (PDMS) based platform that modeled the physiologically relevant stiffness of brain in both …

Noninvasive Measurement Of Electrical Events Associated With A Single Chlorovirus Infection Of A Microalgal Cell, Seung-Woo Lee, Eun-Hee Lee, Gerhard Thiel, James L. Van Etten, Ravi Saraf

Department of Chemical and Biomolecular Engineering: Faculty Publications

Chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) contains a viral-encoded K⁺ channel imbedded in its internal membrane, which triggers host plasma membrane depolarization during virus infection. This early stage of infection was monitored at high resolution by recording the cell membrane depolarization of a single Chlorella cell during infection by a single PBCV-1 particle. The measurement was achieved by depositing the cells onto a network of one-dimensional necklaces of Au nanoparticles, which spanned two electrodes 70 μm apart. The nanoparticle necklace array has been shown to behave as a single-electron device at room temperature. The resulting electrochemical field-effect transistor …

Systems Perturbation Analysis Of A Large-Scale Signal Transduction Model Reveals Potentially Influential Candidates For Cancer Therapeutics, Bhanwar Lal Puniya, Laura Allen, Colleen Hochfelde, Mahbubul Majumder, Tomáš Helikar

Department of Biochemistry: Faculty Publications

Dysregulation in signal transduction pathways can lead to a variety of complex disorders, including cancer. Computational approaches such as network analysis are important tools to understand system dynamics as well as to identify critical components that could be further explored as therapeutic targets. Here, we performed perturbation analysis of a large-scale signal transduction model in extracellular environments that stimulate cell death, growth, motility, and quiescence. Each of the model's components was perturbed under both loss-of-function and gain-of-function mutations. Using 1,300 simulations under both types of perturbations across various extracellular conditions, we identified the most and least influential components based on …

Activation Of Erk And Nf-Κb During Hare-Mediated Heparin Uptake Require Only One Of The Four Endocytic Motifs, Madhu S. Pandey, Colton M. Miller, Edward N. Harris, Paul H. Weigel

Department of Biochemistry: Faculty Publications

Fifteen different ligands, including heparin (Hep), are cleared from lymph and blood by the Hyaluronan (HA) Receptor for Endocytosis (HARE; derived from Stabilin-2 by proteolysis), which contains four endocytic motifs (M1-M4). Endocytosis of HARE•Hep complexes is targeted to coated pits by M1, M2, and M3 (Pandey et al, Int. J. Cell Biol. 2015, article ID 524707), which activates ERK1/2 and NF-κB (Pandey et al J. Biol. Chem. 288, 14068–79, 2013). Here, we used a NF-κB promoter-driven luciferase gene assay and cell lines expressing different HARE cytoplasmic domain mutants to identify motifs needed for Hepmediated signaling. Deletion of M1, M2 or …

Fatty Acid Transport Proteins: Targeting Fatp2 As A Gatekeeper Involved In The Transport Of Exogenous Fatty Acids, Paul N. Black, Constance Ahowesso, David Montefusco, Nipun Saini, Concetta C. Dirusso

Department of Biochemistry: Faculty Publications

The fatty acid transport proteins (FATP) are classified as members of the solute carrier 27 (Slc27) family of proteins based on their ability to function in the transport of exogenous fatty acids. These proteins, when localized to the plasma membrane or at intracellular membrane junctions with the endoplasmic reticulum, function as a gate in the regulated transport of fatty acids and thus represent a therapeutic target to delimit the acquisition of fatty acids that contribute to disease as in the case of fatty acid overload. To date, FATP1, FATP2, and FATP4 have been used as targets in the selection of …

Cadmium And Secondary Structure-Dependent Function Of A Degron In The Pca1p Cadmium Exporter, Nathan Smith, Wenzhong Wel, Miaoyun Zhao, Xiaojuan Quin, Javier Seravalli, Heejeong Kim, Jaekwon Lee

Department of Biochemistry: Faculty Publications

Protein turnover is a critical cellular process regulating biochemical pathways and destroying terminally misfolded or damaged proteins. Pca1p, a cadmium exporter in the yeast Saccharomyces cerevisiae, is rapidly degraded by the endoplasmic reticulum-associated degradation (ERAD) system via a cis-acting degron that exists at the 250–350 amino acid region of Pca1p and is transferable to other proteins to serve as a degradation signal. Cadmium stabilizes Pca1p in a manner dependent on the degron. This suggested that cadmium-mediated masking of the degron impedes its interaction with the molecular factors involved in the ERAD. The characteristics and mechanisms of action of the …

Endoplasmic Reticulum-Associated Degradation Of Pca1p, A Polytopic Protein, Via Interaction With The Proteasome At The Membrane, Nathan Smith, David J. Adle, Miaoyun Zhao, Xiaojuan Quin, Heejeong Kim, Jaekwon Lee

Department of Biochemistry: Faculty Publications

Endoplasmic reticulum-associated degradation (ERAD) plays a critical role for destruction of terminally misfolded proteins at the secretory pathway. The system also regulates expression levels of several proteins such as Pca1p, a cadmium exporter in yeast. To gain better insight into the mechanisms underlying ERAD of Pca1p and other polytopic proteins by the proteasome in the cytosol, our study determined the roles for the molecular factors of ERAD in dislodging Pca1p from the ER. Inactivation of the 20S proteasome leads to accumulation of ubiquitinylated Pca1p in the ER membrane, suggesting a role for the proteasome in extraction of Pca1p from the …

Chloroplast Membrane Remodeling During Freezing Stress Is Accompanied By Cytoplasmic Acidification Activating Sensitive To Freezing 2, Allison C. Barnes, Christoph Benning, Rebecca Roston

Department of Biochemistry: Faculty Publications

Low temperature is a seasonal abiotic stress which restricts native plant ranges and crop distributions. Two types of low temperature stress can be distinguished: chilling and freezing. Much work has been done on the mechanisms by which chilling is sensed, but relatively little is known about how plants sense freezing. Recently, SENSITIVE TO FREEZING 2 (SFR2) was identified as a protein which responds in a non-transcriptional manner to freezing. Here, we investigate the cellular conditions which allow SFR2 activation. Using a combination of isolated organelle, whole tissue and whole plant assays, we provide evidence that SFR2 is activated by changes …

Oma1 Links Mitochondrial Protein Quality Control And Tor Signaling To Modulate Physiological Plasticity And Cellular Stress Responses, Iryna Bohovych, Stavroula Kastora, Sara Christianson, Danelle Topil, Heejeong Kim, Teresa Fangman, You J. Zhou, Antoni Barrientos, Jaekwon Lee, Alistair J.P. Brown, Oleh Khalimonchuk

Department of Biochemistry: Faculty Publications

A network of conserved proteases known as the intramitochondrial quality control (IMQC) system is central to mitochondrial protein homeostasis and cellular health. IMQC proteases also appear to participate in establishment of signaling cues for mitochondrion- to-nucleus communication. However, little is known about this process. Here, we show that in Saccharomyces cerevisiae, inactivation of the membrane-bound IMQC protease Oma1 interferes with oxidative-stress responses through enhanced production of reactive oxygen species (ROS) during logarithmic growth and reduced stress signaling via the TORC1-Rim15- Msn2/Msn4 axis. Pharmacological or genetic prevention of ROS accumulation in Oma1-deficient cells restores this defective TOR signaling. Additionally, inactivation …