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Full-Text Articles in Life Sciences

Identification And Characterization Of A Cadmium-Transporting P-Type Atpase In Yeast Saccharomyces Cerevisiae, David J. Adle Dec 2008

Identification And Characterization Of A Cadmium-Transporting P-Type Atpase In Yeast Saccharomyces Cerevisiae, David J. Adle

Department of Biochemistry: Dissertations, Theses, and Student Research

Detoxification and homeostatic acquisition of metal ions are vital for all living organisms. Non-physiological heavy metals are toxic at low concentrations and represent major environmental hazards to human health. In particular, cadmium is a toxic environmental pollutant linked to a number of ailments including cancer, kidney and bone disease and reproductive disorders. The biological effects of cadmium toxicity which lead to human disease and the cellular mechanisms for cadmium defense are ill defined. Thus, the study of heavy metal detoxification systems represents an important research avenue to help combat cadmium related disorders.

The goal of this research project was to …


Expressional Control Of A Cadmium-Transporting P1b-Type Atpase By A Metal Sensing Degradation Signal, David J. Adle, Jaekwon Lee Nov 2008

Expressional Control Of A Cadmium-Transporting P1b-Type Atpase By A Metal Sensing Degradation Signal, David J. Adle, Jaekwon Lee

Department of Biochemistry: Faculty Publications

Cadmium is a highly toxic environmental contaminant implicated in various diseases. Our previous data demonstrated that Pca1, a P1B-type ATPase, plays a critical role in cadmium resistance in yeast S. cerevisiae by extruding intracellular cadmium. This illustrates the first cadmium-specific efflux pump in eukaryotes. In response to cadmium, yeast cells rapidly enhance expression of Pca1 by a post-transcriptional mechanism. To gain mechanistic insights into the cadmium-dependent control of Pca1 expression, we have characterized the pathway for Pca1 turnover and the mechanism of cadmium sensing that leads to up-regulation of Pca1. Pca1 is a short-lived protein (t½ < 5 min) and is subject to ubiquitination when cells are growing in media lacking cadmium. Distinct from many plasma membrane transporters targeted to the vacuole for degradation via endocytosis, cells defective in this pathway did not stabilize Pca1. Rather, Pca1 turnover was dependent on the proteasome. These data suggest that, in the absence of cadmium, Pca1 is targeted for degradation before reaching the plasma membrane. Mapping of the N terminus of Pca1 identified a metal-responding degradation signal encompassing amino acids 250–350. Fusion of this domain to a stable protein demonstrated that it functions autonomously in a metal-responsive manner. Cadmium sensing by cysteine residues within this domain circumvents ubiquitination and degradation of Pca1. These data reveal a new mechanism for substrate-mediated control of P1B …


An Inositolphosphorylceramide Synthase Is Involved In Regulation Of Plant Programmed Cell Death Associated With Defense In Arabidopsis, Wenming Wang, Xiaohua Yang, Samantha Tangchiaburana, Roland Ndeh, Jennifer E. Markham, Yoseph Tsegaye, Teresa M. Dunn, Guo-Liang Wang, Maria Bellizzi, James F. Parsons, Danielle Morrissey, Janis E. Bravo, Daniel V. Lynch, Shunyuan Xiao Nov 2008

An Inositolphosphorylceramide Synthase Is Involved In Regulation Of Plant Programmed Cell Death Associated With Defense In Arabidopsis, Wenming Wang, Xiaohua Yang, Samantha Tangchiaburana, Roland Ndeh, Jennifer E. Markham, Yoseph Tsegaye, Teresa M. Dunn, Guo-Liang Wang, Maria Bellizzi, James F. Parsons, Danielle Morrissey, Janis E. Bravo, Daniel V. Lynch, Shunyuan Xiao

Department of Biochemistry: Faculty Publications

The Arabidopsis thaliana resistance gene RPW8 triggers the hypersensitive response (HR) to restrict powdery mildew infection via the salicylic acid–dependent signaling pathway. To further understand how RPW8 signaling is regulated, we have conducted a genetic screen to identify mutations enhancing RPW8-mediated HR-like cell death (designated erh). Here, we report the isolation and characterization of the Arabidopsis erh1 mutant, in which the At2g37940 locus is knocked out by a T-DNA insertion. Loss of function of ERH1 results in salicylic acid accumulation, enhanced transcription of RPW8 and RPW8-dependent spontaneous HR-like cell death in leaf tissues, and reduction in plant stature. …


The Very-Long-Chain Hydroxy Fatty Acyl-Coa Dehydratase Pasticcino2 Is Essential And Limiting For Plant Development, Liên Bach, Louise V. Michaelson, Richard Haslam, Yannick Bellec, Lionel Gissot, Jessica Marion, Marco Da Costa, Jean-Pierre Boutin, Martine Miquel, Frédérique Tellier, Frederic Domergue, Jennifer E. Markham, Frederic Beaudoin, Johnathan A. Napier, Jean-Denis Faure Sep 2008

The Very-Long-Chain Hydroxy Fatty Acyl-Coa Dehydratase Pasticcino2 Is Essential And Limiting For Plant Development, Liên Bach, Louise V. Michaelson, Richard Haslam, Yannick Bellec, Lionel Gissot, Jessica Marion, Marco Da Costa, Jean-Pierre Boutin, Martine Miquel, Frédérique Tellier, Frederic Domergue, Jennifer E. Markham, Frederic Beaudoin, Johnathan A. Napier, Jean-Denis Faure

Department of Biochemistry: Faculty Publications

Very-long-chain fatty acids (VLCFAs) are synthesized as acyl-CoAs by the endoplasmic reticulum-localized elongase multiprotein complex. Two Arabidopsis genes are putative homologues of the recently identified yeast 3-hydroxy-acyl-CoA dehydratase (PHS1), the third enzyme of the elongase complex. We showed that Arabidopsis PASTICCINO2 (PAS2) was able to restore phs1 cytokinesis defects and sphingolipid long chain base overaccumulation. Conversely, the expression of PHS1 was able to complement the developmental defects and the accumulation of long chain bases of the pas2–1 mutant. The pas2–1 mutant was characterized by a general reduction of VLCFA pools in seed storage triacylglycerols, cuticular waxes, …


Intraretinal Signaling By Ganglion Cell Photoreceptors To Dopaminergic Amacrine Neurons, Dao-Qi Zhang, Kwoon Y. Wong, Patricia J. Sollars, David M. Berson, Gary E. Pickard, Douglas G. Mcmahon Sep 2008

Intraretinal Signaling By Ganglion Cell Photoreceptors To Dopaminergic Amacrine Neurons, Dao-Qi Zhang, Kwoon Y. Wong, Patricia J. Sollars, David M. Berson, Gary E. Pickard, Douglas G. Mcmahon

School of Veterinary and Biomedical Sciences: Faculty Publications

Retinal dopaminergic amacrine neurons (DA neurons) play a central role in reconfiguring retinal function according to prevailing illumination conditions, yet the mechanisms by which light regulates their activity are poorly understood. We investigated the means by which sustained light responses are evoked in DA neurons. Sustained light responses were driven by cationic currents and persisted in vitro and in vivo in the presence of L-AP4, a blocker of retinal ON-bipolar cells. Several characteristics of these L-AP4-resistant light responses suggested that they were driven by melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs), including long latencies, marked poststimulus persistence, and a peak …


Regulation Of The Bioavailability Of Thioredoxin In The Lens By A Specific Thioredoxin-Binding Protein (Tbp-2), Namal P.M. Liyanage, M. Rohan Fernando, Marjorie F. Lou Aug 2008

Regulation Of The Bioavailability Of Thioredoxin In The Lens By A Specific Thioredoxin-Binding Protein (Tbp-2), Namal P.M. Liyanage, M. Rohan Fernando, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

Thioredoxin (TRx) is known to control redox homeostasis in cells. In recent years, a specific TRx binding protein called thioredoxin binding protein-2 (TBP-2) was found in other cell types and it appeared to negatively regulate TRx bioavailability and thereby control TRx biological function. In view of the sensitivity of lens transparency to redox status, proper regulation of TRx bioavailability is of the utmost importance. This study was conducted to examine the presence and function of TBP-2 in human lens epithelial cells (HLE B3). We cloned human lens TBP-2 from a human cDNA library (GenBank accession number AY 594328) and showed …


The Ligand-Binding Profile Of Hare: Hyaluronan And Chondroitin Sulfates A, C, And D Bind To Overlapping Sites Distinct From The Sites For Heparin, Acetylated Low-Density Lipoprotein, Dermatan Sulfate, And Cs-E, Ed Harris, Paul H. Weigel Aug 2008

The Ligand-Binding Profile Of Hare: Hyaluronan And Chondroitin Sulfates A, C, And D Bind To Overlapping Sites Distinct From The Sites For Heparin, Acetylated Low-Density Lipoprotein, Dermatan Sulfate, And Cs-E, Ed Harris, Paul H. Weigel

Department of Biochemistry: Faculty Publications

Abstract The hyaluronic acid receptor for endocytosis (HARE)/ Stabilin-2 is the primary systemic scavenger receptor for hyaluronan (HA), the chondroitin sulfates (CS), dermatan sulfate (DS), and nonglycosaminoglycan (GAG) ligands such as acetylated low-density lipoprotein (AcLDL), pro-collagen propeptides, and advanced glycation end products. We recently discovered that HARE is also a systemic scavenger receptor for heparin (Hep) (Harris EN, Weigel JA, Weigel PH. 2008. The human hyaluronan receptor for endocytosis [HARE/Stabilin-2] is a systemic clearance receptor for heparin. J Biol Chem. 283:17341–17350). Our goal was to map the binding sites of eight different ligands within HARE. We used biotinylated GAGs and …


The Cytoplasmic Domain Of The Hyaluronan Receptor For Endocytosis (Hare) Contains Multiple Endocytic Motifs Targeting Coated Pit-Mediated Internalization, Madhu S. Pandey, Ed Harris, Janet A. Weigel, Paul H. Weigel Aug 2008

The Cytoplasmic Domain Of The Hyaluronan Receptor For Endocytosis (Hare) Contains Multiple Endocytic Motifs Targeting Coated Pit-Mediated Internalization, Madhu S. Pandey, Ed Harris, Janet A. Weigel, Paul H. Weigel

Department of Biochemistry: Faculty Publications

The hyaluronic acid (HA) receptor for endocytosis (HARE) is the primary scavenger receptor for HA and chondroitin sulfates in mammals. The two human isoforms of HARE (full-length 315-kDa and a 190-kDa proteolytic cleavage product), which are type I single-pass membrane proteins, are highly expressed in sinusoidal endothelial cells of lymph nodes, liver, and spleen. Their identical HARE cytoplasmic domains contain four candidate AP-2/clathrin-mediated endocytic signaling motifs as follows: YSYFRI2485, FQHF2495, NPLY2519, and DPF2534 (315-HARE numbering). Stably transfected cells expressing 190-HARE(ΔYSYFRI), 190-HARE(ΔFQHF), or 190-HARE(ΔNPLY) (lacking Motifs 1, 2, or 3) had decreased 125I-HA …


Selenoproteins Mediate T Cell Immunity Through An Antioxidant Mechanism, Rajeev K. Shrimali, Robert D. Irons, Bradley A. Carlson, Yasuyo Sano, Vadim N. Gladyshev, Jin Mo Park, Dolph L. Hatfield Jul 2008

Selenoproteins Mediate T Cell Immunity Through An Antioxidant Mechanism, Rajeev K. Shrimali, Robert D. Irons, Bradley A. Carlson, Yasuyo Sano, Vadim N. Gladyshev, Jin Mo Park, Dolph L. Hatfield

Vadim Gladyshev Publications

Selenium is an essential dietary element with antioxidant roles in immune regulation, but there is little understanding of how this element acts at the molecular level in host defense and inflammatory disease. Selenium is incorporated into the amino acid selenocysteine (Sec), which in turn is inserted into selenoproteins in a manner dependent on Sec tRNA[Ser]Sec. To investigate the molecular mechanism that links selenium to T cell immunity, we generated mice with selenoprotein-less T cells by cell type-specific ablation of the Sec tRNA[Ser]Sec gene (trsp). Herein, we show that these mutant mice exhibit decreased pools of …


Sphingolipid Long-Chain Base Hydroxylation Is Important For Growth And Regulation Of Sphingolipid Content And Composition In Arabidopsis, Ming Chen, Jennifer E. Markham, Charles R. Dietrich, Jan G. Jaworski, Edgar B. Cahoon Jul 2008

Sphingolipid Long-Chain Base Hydroxylation Is Important For Growth And Regulation Of Sphingolipid Content And Composition In Arabidopsis, Ming Chen, Jennifer E. Markham, Charles R. Dietrich, Jan G. Jaworski, Edgar B. Cahoon

Department of Biochemistry: Faculty Publications

Sphingolipids are structural components of endomembranes and function through their metabolites as bioactive regulators of cellular processes such as programmed cell death. A characteristic feature of plant sphingolipids is their high content of trihydroxy long-chain bases (LCBs) that are produced by the LCB C-4 hydroxylase. To determine the functional significance of trihydroxy LCBs in plants, T-DNA double mutants and RNA interference suppression lines were generated for the two Arabidopsis thaliana LCB C-4 hydroxylase genes Sphingoid Base Hydroxylase1 (SBH1) and SBH2. These plants displayed reductions in growth that were dependent on the content of trihydroxy LCBs in sphingolipids. …


Platyhelminth Mitochondrial And Cytosolic Redox Homeostasis Is Controlled By A Single Thioredoxin Glutathione Reductase And Dependent On Selenium And Glutathione, Mariana Bonilla, Ana Denicola, Sergey V. Novoselov, Anton A. Turanov, Anna Protasio, Darwin Izmendi, Vadim N. Gladyshev, Gustavo Salinas Jun 2008

Platyhelminth Mitochondrial And Cytosolic Redox Homeostasis Is Controlled By A Single Thioredoxin Glutathione Reductase And Dependent On Selenium And Glutathione, Mariana Bonilla, Ana Denicola, Sergey V. Novoselov, Anton A. Turanov, Anna Protasio, Darwin Izmendi, Vadim N. Gladyshev, Gustavo Salinas

Vadim Gladyshev Publications

Platyhelminth parasites are a major health problem in developing countries. In contrast to their mammalian hosts, platyhelminth thiol-disulfide redox homeostasis relies on linked thioredoxin-glutathione systems, which are fully dependent on thioredoxin-glutathione reductase (TGR), a promising drug target. TGR is a homodimeric enzyme comprising a glutaredoxin domain and thioredoxin reductase (TR) domains with a C-terminal redox center containing selenocysteine (Sec). In this study, we demonstrate the existence of functional linked thioredoxin-glutathione systems in the cytosolic and mitochondrial compartments of Echinococcus granulosus, the platyhelminth responsible for hydatid disease. The glutathione reductase (GR) activity of TGR exhibited hysteretic behavior regulated by the …


Tendinopathy Discrimination By Use Of Spatial Frequency Parameters In Ultrasound B-Mode Images, Gregory R. Bashford, Nicholas Tomsen, Shruti Arya, Judith M. Burnfield, Kornelia Kulig May 2008

Tendinopathy Discrimination By Use Of Spatial Frequency Parameters In Ultrasound B-Mode Images, Gregory R. Bashford, Nicholas Tomsen, Shruti Arya, Judith M. Burnfield, Kornelia Kulig

Biomedical Imaging and Biosignal Analysis Laboratory

The structural characteristics of a healthy tendon are related to the anisotropic speckle patterns observed in ultrasonic images. This speckle orientation is disrupted upon damage to the tendon structure as observed in patients with tendinopathy. Quantification of the structural appearance of tendon shows promise in creating a tool for diagnosing, prognosing, or measuring changes in tendon organization over time. The current work describes a first step taken towards this goal—classification of Achilles tendon images into tendinopathy and control categories. Eight spatial frequency parameters were extracted from regions of interest on tendon images, filtered and classified using linear discriminant analysis. Resulting …


Molybdoproteomes And Evolution Of Molybdenum Utilization, Yan Zhang, Vadim N. Gladyshev Apr 2008

Molybdoproteomes And Evolution Of Molybdenum Utilization, Yan Zhang, Vadim N. Gladyshev

Vadim Gladyshev Publications

The trace element molybdenum (Mo) is utilized in many life forms, where it is a key component of several enzymes involved in nitrogen, sulfur, and carbon metabolism. With the exception of nitrogenase, Mo is bound in proteins to a pterin, thus forming the molybdenum cofactor (Moco) at the catalytic sites of molybdoenzymes. Although a number of molybdoenzymes are well characterized structurally and functionally, evolutionary analyses of Mo utilization are limited. Here, we carried out comparative genomic and phylogenetic analyses to examine occurrence and evolution of Mo utilization in bacteria, archaea, and eukaryotes at the level of (i) Mo transport and …


Structure And Catalytic Mechanism Of Eukaryotic Selenocysteine Synthase, Oleg M. Ganichkin, Xue-Ming Xu, Bradley A. Carlson, Heiko Mix, Dolph L. Hatfield, Vadim N. Gladyshev, Markus C. Wahl Feb 2008

Structure And Catalytic Mechanism Of Eukaryotic Selenocysteine Synthase, Oleg M. Ganichkin, Xue-Ming Xu, Bradley A. Carlson, Heiko Mix, Dolph L. Hatfield, Vadim N. Gladyshev, Markus C. Wahl

Vadim Gladyshev Publications

In eukaryotes and Archaea, selenocysteine synthase (SecS) converts O-phospho-L-seryl-tRNA[Ser]Sec into selenocysteyltRNA[Ser]Sec using selenophosphate as the selenium donor compound. The molecular mechanisms underlying SecS activity are presently unknown. We have delineated a 450-residue core of mouse SecS, which retained full selenocysteyl-tRNA[Ser]Sec synthesis activity, and determined its crystal structure at 1.65Å resolution. SecS exhibits three domains that place it in the fold type I family of pyridoxal phosphate (PLP)-dependent enzymes. Two SecS monomers interact intimately and together build up two identical active sites around PLP in a Schiff-base linkage with lysine 284. Two SecS dimers further …


The Pyruvate, Orthophosphate Dikinase Regulatory Proteins Of Arabidopsis Possess A Novel, Unprecedented Ser/Thr Protein Kinase Primary Structure, Chris J. Chastain, Wenxin Xu, Kate Parsley, Gautam Sarath, Jullian Hebberd, Raymond Chollet Feb 2008

The Pyruvate, Orthophosphate Dikinase Regulatory Proteins Of Arabidopsis Possess A Novel, Unprecedented Ser/Thr Protein Kinase Primary Structure, Chris J. Chastain, Wenxin Xu, Kate Parsley, Gautam Sarath, Jullian Hebberd, Raymond Chollet

Department of Biochemistry: Faculty Publications

Pyruvate, orthophosphate dikinase (PPDK) is a ubiquitous, low-abundance metabolic enzyme of undetermined function in C3 plants. Its activity in C3 chloroplasts is light-regulated via reversible phosphorylation of an active-site Thr residue by the PPDK regulatory protein (RP), a most unusual bifunctional protein kinase (PK)/ protein phosphatase (PP). In this paper we document the molecular cloning and functional analysis of the two unique C3 RPs in Arabidopsis thaliana. The first of these, AtRP1, encodes a typical chloroplast-targeted, bifunctional C4-like RP. The second RP gene, AtRP2, encodes a monofunctional polypeptide that possesses in vitro RP-like PK activity but lacks PP activity, …


Emergent Decision-Making In Biological Signal Transduction Networks, Tomáš Helikar, John Konvalina, Jack Heidel, Jim A. Rogers Feb 2008

Emergent Decision-Making In Biological Signal Transduction Networks, Tomáš Helikar, John Konvalina, Jack Heidel, Jim A. Rogers

Department of Biochemistry: Faculty Publications

The complexity of biochemical intracellular signal transduction networks has led to speculation that the high degree of interconnectivity that exists in these networks transforms them into an information processing network. To test this hypothesis directly, a large scale model was created with the logical mechanism of each node described completely to allow simulation and dynamical analysis. Exposing the network to tens of thousands of random combinations of inputs and analyzing the combined dynamics of multiple outputs revealed a robust system capable of clustering widely varying input combinations into equivalence classes of biologically relevant cellular responses. This capability was nontrivial in …


Comparative Analysis Of Selenocysteine Machinery And Selenoproteome Gene Expression In Mouse Brain Identifies Neurons As Key Functional Sites Of Selenium In Mammals, Yan Zhang, You Zhou, Ulrich Schweizer, Nicolai E. Savaskan, Deame Hua, Jonathan Kipnis, Dolph L. Hatfield, Vadim N. Gladyshev Jan 2008

Comparative Analysis Of Selenocysteine Machinery And Selenoproteome Gene Expression In Mouse Brain Identifies Neurons As Key Functional Sites Of Selenium In Mammals, Yan Zhang, You Zhou, Ulrich Schweizer, Nicolai E. Savaskan, Deame Hua, Jonathan Kipnis, Dolph L. Hatfield, Vadim N. Gladyshev

Vadim Gladyshev Publications

Although dietary selenium (Se) deficiency results in phenotypes associated with selenoprotein depletion in various organs, the brain is protected from Se loss. To address the basis for the critical role of Se in brain function, we carried out comparative gene expression analyses for the complete selenoproteome and associated biosynthetic factors. Using the Allen Brain Atlas, we evaluated 159 regions of adult mouse brain and provided experimental analyses of selected selenoproteins. All 24 selenoprotein mRNAs were expressed in the mouse brain. Most strikingly, neurons in olfactory bulb, hippocampus, cerebral cortex, and cerebellar cortex were exceptionally rich in selenoprotein gene expression, in …


The Hyaluronan Receptor For Endocytosis Mediates Hyaluronan-Dependent Signal Transduction Via Extracellular Signal-Regulated Kinases, Svetlana V. Kyosseva, Ed Harris, Paul H. Weigel Jan 2008

The Hyaluronan Receptor For Endocytosis Mediates Hyaluronan-Dependent Signal Transduction Via Extracellular Signal-Regulated Kinases, Svetlana V. Kyosseva, Ed Harris, Paul H. Weigel

Department of Biochemistry: Faculty Publications

The hyaluronan (HA) receptor for endocytosis (HARE) mediates the endocytotic clearance of HA and other glycosaminoglycans from lymph and blood. Two isoforms of human HARE, 315- and 190-kDa, are highly expressed in sinusoidal endothelial cells of liver, lymph node, and spleen; HARE is also in specialized cells in the eye, heart, brain, and kidney. Here we determined whether HA binding to HARE initiates intracellular signaling in Flp-In 293 cells stably expressing either the 315- and 190-kDa HARE or the 190-kDa HARE alone. HARE was co-immunoprecipitated with extracellular signal-regulated kinase 1 and 2 (ERK1/2), c-Jun N-terminal protein kinase (JNK), and p38 …


Functional Domains Of The Fatty Acid Transport Proteins: Studies Using Protein Chimeras, Concetta C. Dirusso, Dina Darwis, Thomas Obermeyer, Paul N. Black Jan 2008

Functional Domains Of The Fatty Acid Transport Proteins: Studies Using Protein Chimeras, Concetta C. Dirusso, Dina Darwis, Thomas Obermeyer, Paul N. Black

Department of Biochemistry: Faculty Publications

Fatty acid transport proteins (FATP) function in fatty acid trafficking pathways, several of which have been shown to participate in the transport of exogenous fatty acids into the cell. Members of this protein family also function as acyl CoA synthetases with specificity towards very long chain fatty acids or bile acids. These proteins have two identifying sequence motifs: The ATP/AMP motif, an approximately 100 amino acid segment required for ATP binding and common to members of the adenylate-forming super family of proteins, and the FATP/VLACS motif that consists of approximately 50 amino acid residues and is restricted to members of …


Development Of Srap, Srap-Rga, Rapd, And Scar Markers Linked With A Fusarium Wilt Resistance Gene In Eggplant, Nedim Mutlu, Filiz Hatice Boyacı, Münevver Göçmen, Kazım Abak Jan 2008

Development Of Srap, Srap-Rga, Rapd, And Scar Markers Linked With A Fusarium Wilt Resistance Gene In Eggplant, Nedim Mutlu, Filiz Hatice Boyacı, Münevver Göçmen, Kazım Abak

Department of Biochemistry: Faculty Publications

Fusarium wilt (Fusarium oxysporum Schlecht. f. sp. melongenae) is a vascular disease of eggplant (Solanum melon­gena L.). The objectives of this work were (1) to confirm the monogenic inheritance of fusarium wilt resistance in eggplant, (2) to identify molecular markers linked to this resistance, and (3) to develop SCAR markers from most informative markers. We report the tagging of the gene for resistance to fusarium wilt (FOM) in eggplant using SRAP, RGA, SRAP-RGA and RAPD markers. Analysis of segregation data confirmed the monogenic inheritance of resistance. DNA from F2 and BC1 populations of eggplant segregating for …


Function And Redox State Of Mitochondrial Localized Cysteine-Rich Proteins Important In The Assembly Of Cytochrome C Oxidase, Oleh Khalimonchuk, Dennis R. Winge Jan 2008

Function And Redox State Of Mitochondrial Localized Cysteine-Rich Proteins Important In The Assembly Of Cytochrome C Oxidase, Oleh Khalimonchuk, Dennis R. Winge

Department of Biochemistry: Faculty Publications

The cytochrome c oxidase (CcO) complex of the mitochondrial respiratory chain exists within the mitochondrial inner membrane (IM). The biogenesis of the complex is a multi-faceted process requiring multiple assembly factors that function on both faces of the IM. Formation of the two copper centers of CcO occurs within the intermembrane space (IMS) and is dependent on assembly factors with critical cysteinyl thiolates. Two classes of assembly factors exist, one group being soluble IMS proteins and the second class being proteins tethered to the IM. A common motif in the soluble assembly factors is a duplicated Cx9C sequence …


Coa2 Is An Assembly Factor For Yeast Cytochrome C Oxidase Biogenesis That Facilitates The Maturation Of Cox1, Fabien Pierrel, Oleh Khalimonchuk, Paul A. Cobine, Megan Bestwick, Dennis R. Winge Jan 2008

Coa2 Is An Assembly Factor For Yeast Cytochrome C Oxidase Biogenesis That Facilitates The Maturation Of Cox1, Fabien Pierrel, Oleh Khalimonchuk, Paul A. Cobine, Megan Bestwick, Dennis R. Winge

Department of Biochemistry: Faculty Publications

The assembly of cytochrome c oxidase (CcO) in yeast mitochondria is dependent on a new assembly factor designated Coa2. Coa2 was identified from its ability to suppress the respiratory deficiency of coa1 Δ and shy1 Δ cells. Coa1 and Shy1 function at an early step in maturation of the Cox1 subunit of CcO. Coa2 functions downstream of the Mss51-Coa1 step in Cox1 maturation and likely concurrent with the Shy1-related heme a3 insertion into Cox1. Coa2 interacts with Shy1. Cells lacking Coa2 show a rapid degradation of newly synthesized Cox1. Rapid Cox1 proteolysis also occurs in shy1 Δ cells, suggesting …


A Functional Link Between Housekeeping Selenoproteins And Phase Ii Enzymes, Aniruddha Sengupta, Bradley A. Carlson, James A. Weaver, Sergey V. Novoselov, Dmitri E. Fomenko, Vadim N. Gladyshev, Dolph Hatfield Jan 2008

A Functional Link Between Housekeeping Selenoproteins And Phase Ii Enzymes, Aniruddha Sengupta, Bradley A. Carlson, James A. Weaver, Sergey V. Novoselov, Dmitri E. Fomenko, Vadim N. Gladyshev, Dolph Hatfield

Vadim Gladyshev Publications

Sec (selenocysteine) is biosynthesized on its tRNA and incorporated into selenium-containing proteins (selenoproteins) as the 21st amino acid residue. Selenoprotein synthesis is dependent on Sec tRNA and the expression of this class of proteins can be modulated by altering Sec tRNA expression. The gene encoding Sec tRNA (Trsp) is a single-copy gene and its targeted removal in liver demonstrated that selenoproteins are essential for proper function wherein their absence leads to necrosis and hepatocellular degeneration. In the present study, we found that the complete loss of selenoproteins in liver was compensated for by an enhanced expression of several phase II …


Functional Characterization Of Alternatively Spliced Human Secisbp2 Transcript Variants, Laura V. Papp, Junning Wang, Derek Kennedy, Didier Boucher, Yan Zhang, Vadim N. Gladyshev, Ravindra N. Singh, Kum Kum Khanna Jan 2008

Functional Characterization Of Alternatively Spliced Human Secisbp2 Transcript Variants, Laura V. Papp, Junning Wang, Derek Kennedy, Didier Boucher, Yan Zhang, Vadim N. Gladyshev, Ravindra N. Singh, Kum Kum Khanna

Vadim Gladyshev Publications

Synthesis of selenoproteins depends on decoding of the UGA stop codon as the amino acid selenocysteine (Sec). This process requires the presence of a Sec insertion sequence element (SECIS) in the 3’-untranslated region of selenoprotein mRNAs and its interaction with the SECIS binding protein 2 (SBP2). In humans, mutations in the SBP2-encoding gene Sec insertion sequence binding protein 2 (SECISBP2) that alter the amino acid sequence or cause splicing defects lead to abnormal thyroid hormone metabolism. Herein, we present the first in silico and in vivo functional characterization of alternative splicing of SECISBP2. We report a complex splicing …


Selenoproteinless Animals: Selenophosphate Synthetase Sps1 Functions In A Pathway Unrelated To Selenocysteine Biosynthesis, Alexey V. Lobanov, Dolph Hatfield, Vadim N. Gladyshev Jan 2008

Selenoproteinless Animals: Selenophosphate Synthetase Sps1 Functions In A Pathway Unrelated To Selenocysteine Biosynthesis, Alexey V. Lobanov, Dolph Hatfield, Vadim N. Gladyshev

Vadim Gladyshev Publications

Proteins containing the 21st amino acid, selenocysteine (Sec), have been described in all three domains of life, but the composition of selenoproteomes in organisms varies significantly. Here, we report that aquatic arthropods possess many selenoproteins also detected in other animals and unicellular eukaryotes, and that most of these proteins were either lost or replaced with cysteine-containing homologs in insects. As a result of this selective selenoproteome reduction, fruit flies and mosquitoes have three known selenoproteins, and the honeybee, Apis mellifera, a single detected candidate selenoprotein. Moreover, we identified the red flour beetle, Tribolium castaneum, and the silkworm, Bombyx …


Trends In Selenium Utilization In Marine Microbial World Revealed Through The Analysis Of The Global Ocean Sampling (Gos) Project, Yan Zhang, Vadim N. Gladyshev Jan 2008

Trends In Selenium Utilization In Marine Microbial World Revealed Through The Analysis Of The Global Ocean Sampling (Gos) Project, Yan Zhang, Vadim N. Gladyshev

Vadim Gladyshev Publications

Selenium is an important trace element that occurs in proteins in the form of selenocysteine (Sec) and in tRNAs in the form of selenouridine. Recent large-scale metagenomics projects provide an opportunity for understanding global trends in trace element utilization. Herein, we characterized the selenoproteome of the microbial marine community derived from the Global Ocean Sampling (GOS) expedition. More than 3,600 selenoprotein gene sequences belonging to 58 protein families were detected, including sequences representing 7 newly identified selenoprotein families, such as homologs of ferredoxin– thioredoxin reductase and serine protease. In addition, a new eukaryotic selenoprotein family, thiol reductase GILT, was identified. …


Selenodb 1.0 : A Database Of Selenoprotein Genes, Proteins And Secis Elements, Sergi Castellano, Vadim N. Gladyshev, Roderic Guigo, Marla J. Berry Jan 2008

Selenodb 1.0 : A Database Of Selenoprotein Genes, Proteins And Secis Elements, Sergi Castellano, Vadim N. Gladyshev, Roderic Guigo, Marla J. Berry

Vadim Gladyshev Publications

Selenoproteins are a diverse group of proteins usually misidentified and misannotated in sequence databases. The presence of an in-frame UGA (stop) codon in the coding sequence of selenoprotein genes precludes their identification and correct annotation. The in-frame UGA codons are recoded to cotranslationally incorporate selenocysteine, a rare selenium-containing amino acid. The development of ad hoc experimental and, more recently, computational approaches have allowed the efficient identification and characterization of the selenoproteomes of a growing number of species. Today, dozens of selenoprotein families have been described and more are being discovered in recently sequenced species, but the correct genomic annotation is …


Loss Of Housekeeping Selenoprotein Expression In Mouse Liver Modulates Lipoprotein Metabolism, Aniruddha Sengupta, Bradley A. Carlson, Victoria J. Hoffmann, Vadim N. Gladyshev, Dolph L. Hatfield Jan 2008

Loss Of Housekeeping Selenoprotein Expression In Mouse Liver Modulates Lipoprotein Metabolism, Aniruddha Sengupta, Bradley A. Carlson, Victoria J. Hoffmann, Vadim N. Gladyshev, Dolph L. Hatfield

Vadim Gladyshev Publications

Selenium is incorporated into proteins as selenocysteine (Sec), which is dependent on its specific tRNA, designated tRNA [Ser]Sec. Targeted removal of the tRNA [Ser]Sec gene (Trsp) in mouse hepatocytes previously demonstrated the importance of selenoproteins in liver function. Herein, analysis of plasma proteins in this Trsp knockout mouse revealed increases in apolipoprotein E (ApoE) that was accompanied by elevated plasma cholesterol levels. The expression of genes involved in cholesterol biosynthesis, metabolism and transport were also altered in knockout mice. Additionally, in two transgenic Trsp mutant mouse lines (wherein only housekeeping selenoprotein synthesis was restored), the expression …


Comparative Genomic Analyses Of Copper Transporters And Cuproproteomes Reveal Evolutionary Dynamics Of Copper Utilization And Its Link To Oxygen, Perry Ridge, Yan Zhang, Vadim N. Gladyshev Jan 2008

Comparative Genomic Analyses Of Copper Transporters And Cuproproteomes Reveal Evolutionary Dynamics Of Copper Utilization And Its Link To Oxygen, Perry Ridge, Yan Zhang, Vadim N. Gladyshev

Vadim Gladyshev Publications

Copper is an essential trace element in many organisms and is utilized in all domains of life. It is often used as a cofactor of redox proteins, but is also a toxic metal ion. Intracellular copper must be carefully handled to prevent the formation of reactive oxygen species which pose a threat to DNA, lipids, and proteins. In this work, we examined patterns of copper utilization in prokaryotes by analyzing the occurrence of copper transporters and copper-containing proteins. Many organisms, including those that lack copper-dependent proteins, had copper exporters, likely to protect against copper ions that inadvertently enter the cell. …


Reduced Reliance On The Trace Element Selenium During Evolution Of Mammals, Alexey Lobanov, Dolph Hatfield, Vadim N. Gladyshev Jan 2008

Reduced Reliance On The Trace Element Selenium During Evolution Of Mammals, Alexey Lobanov, Dolph Hatfield, Vadim N. Gladyshev

Vadim Gladyshev Publications

Background: Selenium (Se) is an essential trace element that occurs in proteins in the form of selenocysteine (Sec). It is transported throughout the body in the form of Sec residues in Selenoprotein P (SelP), a plasma protein of unclear origin recently proposed as an experimental marker of dietary Se status.
Results: Here, we report that the amino-terminal domain of SelP is distantly related to ancestral bacterial thiol oxidoreductases of the thioredoxin superfamily, and that its carboxy-terminal Se transport domain may have originated in early metazoan evolution by de novo accumulation of Sec residues. Reconstruction of evolutionary changes in the Se …