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2011

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Articles 31 - 60 of 266

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

A Brain-Derived Mecp2 Complex Supports A Role For Mecp2 In Rna Processing, Steven W. Long, Jenny Y. Y. Ooi, Peter M. Yau, Peter L. Jones Oct 2011

A Brain-Derived Mecp2 Complex Supports A Role For Mecp2 In Rna Processing, Steven W. Long, Jenny Y. Y. Ooi, Peter M. Yau, Peter L. Jones

Peter Jones Lab Publications

Mutations in MECP2 (methyl-CpG-binding protein 2) are linked to the severe postnatal neurodevelopmental disorder RTT (Rett syndrome). MeCP2 was originally characterized as a transcriptional repressor that preferentially bound methylated DNA; however, recent results indicate MeCP2 is a multifunctional protein. MeCP2 binding is now associated with certain expressed genes and involved in nuclear organization as well, indicating that its gene regulatory function is context-dependent. In addition, MeCP2 is proposed to regulate mRNA splicing and a mouse model for RTT shows aberrant mRNA splicing. To further understand MeCP2 and potential roles in RTT pathogenesis, we have employed a biochemical approach to identify ...


Activation Of Mmp-9 By Human Lung Epithelial Cells In Response To The Cystic Fibrosis-Associated Pathogen Burkholderia Cenocepacia Reduced Wound Healing In Vitro, Ciara Wright ], Ruth Pilkington, Máire Callaghan, Siobhan Mcclean Oct 2011

Activation Of Mmp-9 By Human Lung Epithelial Cells In Response To The Cystic Fibrosis-Associated Pathogen Burkholderia Cenocepacia Reduced Wound Healing In Vitro, Ciara Wright ], Ruth Pilkington, Máire Callaghan, Siobhan Mcclean

Articles

Burkholderia cepacia complex is a group of bacterial pathogens that cause opportunistic infections in cystic fibrosis (CF). The most virulent of these is Burkholderia cenocepacia. Matrix metalloproteinases (MMPs) are upregulated in CF patients. The aim of this work was to examine the role of MMPs in the pathogenesis of B. cepacia complex, which has not been explored to date. Real-time PCR analysis showed that B. cenocepacia infection upregulated MMP-2 and MMP-9 genes in the CF lung cell line CFBE41o- within 1 h, whereas MMP-2, -7, and -9 genes were upregulated in the non-CF lung cell line 16HBE14o-. Conditioned media from ...


Iron Insufficiency Compromises Motor Neurons And Their Mitochondrial Function In Irp2-Null Mice, Suh Young Jeong, Daniel R. Crooks, Hayden Wilson-Ollivierre, Manik C. Ghosh, Rachid Sougrat, Jaekwon Lee, Sharon Cooperman, James B. Mitchell, Carole Beaumont, Tracey A. Rouault Oct 2011

Iron Insufficiency Compromises Motor Neurons And Their Mitochondrial Function In Irp2-Null Mice, Suh Young Jeong, Daniel R. Crooks, Hayden Wilson-Ollivierre, Manik C. Ghosh, Rachid Sougrat, Jaekwon Lee, Sharon Cooperman, James B. Mitchell, Carole Beaumont, Tracey A. Rouault

Biochemistry -- Faculty Publications

Genetic ablation of Iron Regulatory Protein 2 (Irp2, Ireb2), which post-transcriptionally regulates iron metabolism genes, causes a gait disorder in mice that progresses to hind-limb paralysis. Here we have demonstrated that misregulation of iron metabolism from loss of Irp2 causes lower motor neuronal degeneration with significant spinal cord axonopathy. Mitochondria in the lumbar spinal cord showed significantly decreased Complex I and II activities, and abnormal morphology. Lower motor neurons appeared to be the most adversely affected neurons, and we show that functional iron starvation due to misregulation of iron import and storage proteins, including transferrin receptor 1 and ferritin, may ...


Differential Interactions Of The Formins Inf2, Mdia1, And Mdia2 With Microtubules, Jeremie Gaillard, Bvinay Ramabhadran, Emmanuelle Neumanne, Pinar Gurel, Laurent Blanchoin, Marylin Vantard, Henry N. Higgs Sep 2011

Differential Interactions Of The Formins Inf2, Mdia1, And Mdia2 With Microtubules, Jeremie Gaillard, Bvinay Ramabhadran, Emmanuelle Neumanne, Pinar Gurel, Laurent Blanchoin, Marylin Vantard, Henry N. Higgs

Open Dartmouth: Faculty Open Access Scholarship

A number of cellular processes use both microtubules and actin filaments, but the molecular machinery linking these two cytoskeletal elements remains to be elucidated in detail. Formins are actin-binding proteins that have multiple effects on actin dynamics, and one formin, mDia2, has been shown to bind and stabilize microtubules through its formin homology 2 (FH2) domain. Here we show that three formins, INF2, mDia1, and mDia2, display important differences in their interactions with microtubules and actin. Constructs containing FH1, FH2, and C-terminal domains of all three formins bind microtubules with high affinity (K(d) < 100 nM). However, only mDia2 binds microtubules at 1:1 stoichiometry, with INF2 and mDia1 showing saturating binding at approximately 1:3 (formin dimer:tubulin dimer). INF2-FH1FH2C is a potent microtubule-bundling protein, an effect that results in a large reduction in catastrophe rate. In contrast, neither mDia1 nor mDia2 is a potent microtubule bundler. The C-termini of mDia2 and INF2 have different functions in microtubule interaction, with mDia2's C-terminus required for high-affinity binding and INF2's C-terminus required for bundling. mDia2's C-terminus directly binds microtubules with submicromolar affinity. These formins also differ in their abilities to bind actin and microtubules simultaneously. Microtubules strongly inhibit actin polymerization by mDia2, whereas they moderately inhibit mDia1 and have no effect on INF2. Conversely, actin monomers inhibit microtubule binding/bundling by INF2 but do not affect mDia1 or mDia2. These differences in interactions with microtubules and actin suggest differential function in cellular processes requiring both cytoskeletal elements.


The Pcdp1 Complex Coordinates The Activity Of Dynein Isoforms To Produce Wild-Type Ciliary Motility, Christen G. Dipetrillo, Elizabeth F. Smith Sep 2011

The Pcdp1 Complex Coordinates The Activity Of Dynein Isoforms To Produce Wild-Type Ciliary Motility, Christen G. Dipetrillo, Elizabeth F. Smith

Open Dartmouth: Faculty Open Access Scholarship

Generating the complex waveforms characteristic of beating cilia requires the coordinated activity of multiple dynein isoforms anchored to the axoneme. We previously identified a complex associated with the C1d projection of the central apparatus that includes primary ciliary dyskinesia protein 1 (Pcdp1). Reduced expression of complex members results in severe motility defects, indicating that C1d is essential for wild-type ciliary beating. To define a mechanism for Pcdp1/C1d regulation of motility, we took a functional and structural approach combined with mutants lacking C1d and distinct subsets of dynein arms. Unlike mutants completely lacking the central apparatus, dynein-driven microtubule sliding velocities ...


Schrödinger And Nietzsche On Life: The Eternal Recurrence Of The Same, Babette Babich Sep 2011

Schrödinger And Nietzsche On Life: The Eternal Recurrence Of The Same, Babette Babich

Working Papers

Schrödinger and Nietzsche on Life: The Eternal Recurrence of the Same

This essay explores Schrödinger’s reflections on measurement, consciousness, and personal identity. Schrödinger’s, What Is Life? is read together with Nietzsche’s own reflections on the same question, in his aphorism What is Life? together with Nietzsche’s teaching of the eternal return of the selfsame. Schrödinger’s own thinking is influenced as is Nietzsche’s by Schopenhauer but Schrödinger also has the Vedic tradition as this influenced Schopenhauer himself in view.


Functional Characterization Of The Saccharomyces Cerevisiae Protein Chl1 Reveals The Role Of Sister Chromatid Cohesion In The Maintenance Of Spindle Length During S-Phase Arrest, Suparna Laha, Shankar Das, Sujata Hajra, Kaustuv Sanyal, Pratima Sinha Sep 2011

Functional Characterization Of The Saccharomyces Cerevisiae Protein Chl1 Reveals The Role Of Sister Chromatid Cohesion In The Maintenance Of Spindle Length During S-Phase Arrest, Suparna Laha, Shankar Das, Sujata Hajra, Kaustuv Sanyal, Pratima Sinha

Open Access Articles

BACKGROUND: Metaphase cells have short spindles for efficient bi-orientation of chromosomes. The cohesin proteins hold sister chromatids together, creating Sister Chromatid Cohesion (SCC) that helps in the maintenance of short spindle lengths in metaphase. The budding yeast protein Chl1p, which has human homologs, is required for DNA damage repair, recombination, transcriptional silencing and aging. This protein is also needed to establish SCC between sister chromatids in S-phase.

RESULTS: In the present study we have further characterized Chl1p for its role in the yeast Saccharomyces cerevisiae when cells are under replication stress. We show that when DNA replication is arrested by ...


Exploring The Roles Of Nucleobase Desolvation And Shape Complementarity During The Misreplication Of O6-Methylguanine, Delia Chavarria, Andrea Ramos Serrano, Ichiro Hirao, Anthony J. Berdis Sep 2011

Exploring The Roles Of Nucleobase Desolvation And Shape Complementarity During The Misreplication Of O6-Methylguanine, Delia Chavarria, Andrea Ramos Serrano, Ichiro Hirao, Anthony J. Berdis

Chemistry Faculty Publications

O6-methylguanine is a miscoding DNA lesion arising from the alkylation of guanine. This report uses the bacteriophage T4 DNA polymerase as a model to probe the roles hydrogen-bonding interactions, shape/size, and nucleobase desolvation during the replication of this miscoding lesion. This was accomplished by using transient kinetic techniques to monitor the kinetic parameters for incorporating and extending natural and non-natural nucleotides. In general, the efficiency of nucleotide incorporation does not depend on the hydrogen-bonding potential of the incoming nucleotide. Instead, nucleobase hydrophobicity and shape complementarity appear to be the preeminent factors controlling nucleotide incorporation. In addition, shape complementarity plays ...


Rna Oxidation Adducts 8-Ohg And 8-Oha Change With Aβ42 Levels In Late-Stage Alzheimer's Disease, Adam M. Weidner, Melissa A. Bradley, Tina L. Beckett, Dana M. Niedowicz, Amy L.S. Dowling, Sergey V. Matveev, Harry Levine, Mark A. Lovell, M. Paul Murphy Sep 2011

Rna Oxidation Adducts 8-Ohg And 8-Oha Change With Aβ42 Levels In Late-Stage Alzheimer's Disease, Adam M. Weidner, Melissa A. Bradley, Tina L. Beckett, Dana M. Niedowicz, Amy L.S. Dowling, Sergey V. Matveev, Harry Levine, Mark A. Lovell, M. Paul Murphy

Sanders-Brown Center on Aging Faculty Publications

While research supports amyloid-β (Aβ) as the etiologic agent of Alzheimer's disease (AD), the mechanism of action remains unclear. Evidence indicates that adducts of RNA caused by oxidation also represent an early phenomenon in AD. It is currently unknown what type of influence these two observations have on each other, if any. We quantified five RNA adducts by gas chromatography/mass spectroscopy across five brain regions from AD cases and age-matched controls. We then used a reductive directed analysis to compare the RNA adducts to common indices of AD neuropathology and various pools of Aβ. Using data from four ...


Computational Protein Design To Re-Engineer Stromal Cell-Derived Factor-1Α (Sdf) Generates An Effective And Translatable Angiogenic Polypeptide Analog, William Hiesinger, Jose Manuel Perez Aguilar, Pavan Atluri, Nicole A. Marotta, John R. Frederick, J Raymond Fitzpatrick, Ryan C. Mccormick, Jeffrey R. Muenzer, Elaine C. Yang, Rebecca D. Levit, Li-Jun Yuan, John W. Macarthur, Jeffery G. Saven, Y Joseph Woo Sep 2011

Computational Protein Design To Re-Engineer Stromal Cell-Derived Factor-1Α (Sdf) Generates An Effective And Translatable Angiogenic Polypeptide Analog, William Hiesinger, Jose Manuel Perez Aguilar, Pavan Atluri, Nicole A. Marotta, John R. Frederick, J Raymond Fitzpatrick, Ryan C. Mccormick, Jeffrey R. Muenzer, Elaine C. Yang, Rebecca D. Levit, Li-Jun Yuan, John W. Macarthur, Jeffery G. Saven, Y Joseph Woo

Departmental Papers (Chemistry)

BACKGROUND: Experimentally, exogenous administration of recombinant stromal cell-derived factor-1α (SDF) enhances neovasculogenesis and cardiac function after myocardial infarction. Smaller analogs of SDF may provide translational advantages including enhanced stability and function, ease of synthesis, lower cost, and potential modulated delivery via engineered biomaterials. In this study, computational protein design was used to create a more efficient evolution of the native SDF protein.

METHODS AND RESULTS: Protein structure modeling was used to engineer an SDF polypeptide analog (engineered SDF analog [ESA]) that splices the N-terminus (activation and binding) and C-terminus (extracellular stabilization) with a diproline segment designed to limit the conformational ...


A Novel Labda-7,13e-Dien-15-Ol-Producing Bifunctional Diterpene Synthase From Selaginella Moellendorffii, Sibongile Mafu, Matthew L. Hillwig, Reuben J. Peters Sep 2011

A Novel Labda-7,13e-Dien-15-Ol-Producing Bifunctional Diterpene Synthase From Selaginella Moellendorffii, Sibongile Mafu, Matthew L. Hillwig, Reuben J. Peters

Biochemistry, Biophysics and Molecular Biology Publications

Vascular plants invariably contain a class II diterpene cyclase (EC 5.5.1.x), as an ent-copalyl diphosphate synthase is required for gibberellin phytohormone biosynthesis. This has provided the basis for evolution of a functionally diverse enzymatic family.[1] These biocatalysts fold their substrate, the general diterpenoid precursor (E,E,E)-geranylgeranyl diphosphate (GGPP), to bring the terminal three carbon-carbon double bonds into proximity with each other, and then carry out bicyclization via a protonation-initiated carbocation cascade reaction. The resulting labda-15-en-8-yl+ diphosphate intermediate is most commonly quenched by deprotonation at an exocyclic methyl, as in the production of labdadienyl/copalyl ...


Single Molecule Analysis Of The Arabidopsis Fra1 Kinesin Shows That It Is A Functional Motor Protein With Unusually High Processivity, Chuanmei Zhu, Ram Dixit Sep 2011

Single Molecule Analysis Of The Arabidopsis Fra1 Kinesin Shows That It Is A Functional Motor Protein With Unusually High Processivity, Chuanmei Zhu, Ram Dixit

Biology Faculty Publications & Presentations

The Arabidopsis FRA1 kinesin contributes to the organization of cellulose microfibrils through an unknown mechanism. The cortical localization of this kinesin during interphase raises the possibility that it transports cell wall-related cargoes along cortical microtubules that either directly or indirectly influence cellulose microfibril patterning. To determine whether FRA1 is an authentic motor protein, we combined bulk biochemical assays and single molecule fluorescence imaging to analyze the motor properties of recombinant, GFP-tagged FRA1 containing the motor and coiled-coil domains (designated as FRA1(707)–GFP). We found that FRA1(707)–GFP binds to microtubules in an ATP-dependent manner and that its ATPase ...


Stomatin-Like Protein 2 Binds Cardiolipin And Regulates Mitochondrial Biogenesis And Function., Darah Christie, Caitlin D Lemke, Isaac M Elias, Luan A Chau, Mark G Kirchhof, Bo Li, Eric H Ball, Stanley D Dunn, Grant M Hatch, Joaquín Madrenas Sep 2011

Stomatin-Like Protein 2 Binds Cardiolipin And Regulates Mitochondrial Biogenesis And Function., Darah Christie, Caitlin D Lemke, Isaac M Elias, Luan A Chau, Mark G Kirchhof, Bo Li, Eric H Ball, Stanley D Dunn, Grant M Hatch, Joaquín Madrenas

Biochemistry Publications

Stomatin-like protein 2 (SLP-2) is a widely expressed mitochondrial inner membrane protein of unknown function. Here we show that human SLP-2 interacts with prohibitin-1 and -2 and binds to the mitochondrial membrane phospholipid cardiolipin. Upregulation of SLP-2 expression increases cardiolipin content and the formation of metabolically active mitochondrial membranes and induces mitochondrial biogenesis. In human T lymphocytes, these events correlate with increased complex I and II activities, increased intracellular ATP stores, and increased resistance to apoptosis through the intrinsic pathway, ultimately enhancing cellular responses. We propose that the function of SLP-2 is to recruit prohibitins to cardiolipin to form cardiolipin-enriched ...


The Effects Of Acute And Chronic Hypoxia On Cortisol, Glucose And Lactate Concentrations In Different Populations Of Three-Spined Stickleback, E. A. O'Connor, T. G. Pottinger, L. U. Sneddon Sep 2011

The Effects Of Acute And Chronic Hypoxia On Cortisol, Glucose And Lactate Concentrations In Different Populations Of Three-Spined Stickleback, E. A. O'Connor, T. G. Pottinger, L. U. Sneddon

Aquaculture Collection

The response of individuals from three different populations of three-spined sticklebacks to acute and chronic periods of hypoxia (4.4 kPa DO, 2.2 mg l-1) were tested using measures of whole-body (WB) cortisol, glucose and lactate. Although there was no evidence of a neuroendocrine stress response to acute hypoxia, fish from the population least likely to experience hypoxia in their native habitat had the largest response to low oxygen, with significant evidence of anaerobic glycolysis after two hours of hypoxia. However, there was no measurable effect of a more prolonged period (seven days) of hypoxia on any of the ...


An Evolutionarily Conserved Rit Gtpase-P38 Mapk Signaling Pathway Mediates Oxidative Stress Resistance, Weikang Cai, Jennifer L. Rudolph, Susan M. W. Harrison, Ling Jin, Aubrey L. Frantz, Douglas A. Harrison, Douglas A. Andres Sep 2011

An Evolutionarily Conserved Rit Gtpase-P38 Mapk Signaling Pathway Mediates Oxidative Stress Resistance, Weikang Cai, Jennifer L. Rudolph, Susan M. W. Harrison, Ling Jin, Aubrey L. Frantz, Douglas A. Harrison, Douglas A. Andres

Molecular and Cellular Biochemistry Faculty Publications

Ras-related small GTP-binding proteins control a wide range of cellular processes by regulating a variety of effector pathways, including prominent roles in the control of mitogen-activated protein kinase (MAPK) cascades. Although the regulatory role(s) for many Ras family GTPases are well established, the physiological function for the Rit/Rin subfamily has been lacking. Here, using both knockout mice and Drosophila models, we demonstrate an evolutionarily conserved role for Rit subfamily GTPases (mammalian Rit and Rin, and the Drosophila RIC homologue) in governing survival in response to oxidative stress. Primary embryonic fibroblasts derived from Rit knockout mice display increased apoptosis ...


Antagonistic Effects Of Cellular Poly(C) Binding Proteins On Vesicular Stomatitis Virus Gene Expression, Phat X. Dinh, Lalit Beura, Debasis Panda, Anshuman Das, Asit K. Pattnaik Sep 2011

Antagonistic Effects Of Cellular Poly(C) Binding Proteins On Vesicular Stomatitis Virus Gene Expression, Phat X. Dinh, Lalit Beura, Debasis Panda, Anshuman Das, Asit K. Pattnaik

Papers in Veterinary and Biomedical Science

Immunoprecipitation and subsequent mass spectrometry analysis of the cellular proteins from cells expressing the vesicular stomatitis virus (VSV) P protein identified the poly(C) binding protein 2 (PCBP2) as one of the P protein-interacting proteins. To investigate the role of PCBP2 in the viral life cycle, we examined the effects of depletion or overexpression of this protein on VSV growth. Small interfering RNA-mediated silencing of PCBP2 promoted VSV replication. Conversely, overexpression of PCBP2 in transfected cells suppressed VSV growth. Further studies revealed that PCBP2 negatively regulates overall viral mRNA accumulation and subsequent genome replication. Coimmunoprecipitation and immunofluorescence microscopic studies showed ...


Drosophila Iap1-Mediated Ubiquitylation Controls Activation Of The Initiator Caspase Dronc Independent Of Protein Degradation, Tom V. Lee, Yun Fan, Shiuan Wang, Mayank Srivastava, Meike Broemer, Pascal Meier, Andreas Bergmann Sep 2011

Drosophila Iap1-Mediated Ubiquitylation Controls Activation Of The Initiator Caspase Dronc Independent Of Protein Degradation, Tom V. Lee, Yun Fan, Shiuan Wang, Mayank Srivastava, Meike Broemer, Pascal Meier, Andreas Bergmann

Molecular, Cell and Cancer Biology Publications

Ubiquitylation targets proteins for proteasome-mediated degradation and plays important roles in many biological processes including apoptosis. However, non-proteolytic functions of ubiquitylation are also known. In Drosophila, the inhibitor of apoptosis protein 1 (DIAP1) is known to ubiquitylate the initiator caspase DRONC in vitro. Because DRONC protein accumulates in diap1 mutant cells that are kept alive by caspase inhibition ("undead" cells), it is thought that DIAP1-mediated ubiquitylation causes proteasomal degradation of DRONC, protecting cells from apoptosis. However, contrary to this model, we show here that DIAP1-mediated ubiquitylation does not trigger proteasomal degradation of full-length DRONC, but serves a non-proteolytic function. Our ...


Translocation Channel Gating Kinetics Balances Protein Translocation Efficiency With Signal Sequence Recognition Fidelity, Steven F. Trueman, Elisabet C. Mandon, Reid Gilmore Sep 2011

Translocation Channel Gating Kinetics Balances Protein Translocation Efficiency With Signal Sequence Recognition Fidelity, Steven F. Trueman, Elisabet C. Mandon, Reid Gilmore

GSBS Student Publications

The transition between the closed and open conformations of the Sec61 complex permits nascent protein insertion into the translocation channel. A critical event in this structural transition is the opening of the lateral translocon gate that is formed by four transmembrane (TM) spans (TM2, TM3, TM7, and TM8 in Sec61p) to expose the signal sequence-binding site. To gain mechanistic insight into lateral gate opening, mutations were introduced into a lumenal loop (L7) that connects TM7 and TM8. The sec61 L7 mutants were found to have defects in both the posttranslational and cotranslational translocation pathways due to a kinetic delay in ...


The Filament-Forming Protein Pil1 Assembles Linear Eisosomes In Fission Yeast, Ruth Kabeche, Suzanne Baldissard, John Hammond, Louisa Howard, James B. Moseley Aug 2011

The Filament-Forming Protein Pil1 Assembles Linear Eisosomes In Fission Yeast, Ruth Kabeche, Suzanne Baldissard, John Hammond, Louisa Howard, James B. Moseley

Open Dartmouth: Faculty Open Access Scholarship

The cortical cytoskeleton mediates a range of cellular activities such as endocytosis, cell motility, and the maintenance of cell rigidity. Traditional polymers, including actin, microtubules, and septins, contribute to the cortical cytoskeleton, but additional filament systems may also exist. In yeast cells, cortical structures called eisosomes generate specialized domains termed MCCs to cluster specific proteins at sites of membrane invaginations. Here we show that the core eisosome protein Pil1 forms linear cortical filaments in fission yeast cells and that purified Pil1 assembles into filaments in vitro. In cells, Pil1 cortical filaments are excluded from regions of cell growth and are ...


The Worlds Of Splicing And Chromatin Collide, J. Adam Hall, Philippe T. Georgel Aug 2011

The Worlds Of Splicing And Chromatin Collide, J. Adam Hall, Philippe T. Georgel

Biological Sciences Faculty Research

Both transcription and splicing take place in a nuclear environment which, at face value, may seem refractory to the efficiency afforded by the coupling of both processes. This environment, chromatin, was once viewed as only a passive packaging system for genetic material, with very little contribution to the variety of nuclear activities occurring within and around it. However, overwhelming evidence now points to the chromatin environment as being highly dynamic, and an active player in nuclear activities.


Laforin, A Dual Specificity Phosphatase Involved In Lafora Disease, Is Present Mainly As Monomeric Form With Full Phosphatase Activity, Vikas V. Dukhande, Devin M. Rogers, Carlos Romá-Mateo, Jordi Donderis, Alberto Marina, Adam O. Taylor, Pascual Sanz, Matthew S. Gentry Aug 2011

Laforin, A Dual Specificity Phosphatase Involved In Lafora Disease, Is Present Mainly As Monomeric Form With Full Phosphatase Activity, Vikas V. Dukhande, Devin M. Rogers, Carlos Romá-Mateo, Jordi Donderis, Alberto Marina, Adam O. Taylor, Pascual Sanz, Matthew S. Gentry

Molecular and Cellular Biochemistry Faculty Publications

Lafora Disease (LD) is a fatal neurodegenerative epileptic disorder that presents as a neurological deterioration with the accumulation of insoluble, intracellular, hyperphosphorylated carbohydrates called Lafora bodies (LBs). LD is caused by mutations in either the gene encoding laforin or malin. Laforin contains a dual specificity phosphatase domain and a carbohydrate-binding module, and is a member of the recently described family of glucan phosphatases. In the current study, we investigated the functional and physiological relevance of laforin dimerization. We purified recombinant human laforin and subjected the monomer and dimer fractions to denaturing gel electrophoresis, mass spectrometry, phosphatase assays, protein-protein interaction assays ...


Mutant Alcohol Dehydrogenase Leads To Improved Ethanol Tolerance In Clostridium Thermocellum, Steven D. Brown, Adam M. Guss, Tatiana V. Karpinets, Jerry M. Parks Aug 2011

Mutant Alcohol Dehydrogenase Leads To Improved Ethanol Tolerance In Clostridium Thermocellum, Steven D. Brown, Adam M. Guss, Tatiana V. Karpinets, Jerry M. Parks

Open Dartmouth: Faculty Open Access Scholarship

Clostridium thermocellum is a thermophilic, obligately anaerobic, Gram-positive bacterium that is a candidate microorganism for converting cellulosic biomass into ethanol through consolidated bioprocessing. Ethanol intolerance is an important metric in terms of process economics, and tolerance has often been described as a complex and likely multigenic trait for which complex gene interactions come into play. Here, we resequence the genome of an ethanol-tolerant mutant, show that the tolerant phenotype is primarily due to a mutated bifunctional acetaldehyde-CoA/alcohol dehydrogenase gene (adhE), hypothesize based on structural analysis that cofactor specificity may be affected, and confirm this hypothesis using enzyme assays. Biochemical ...


The Nucleotide Exchange Factor Ric-8a Is A Chaperone For The Conformationally Dynamic Nucleotide-Free State Of G Alpha I1, Celestine J. Thomas, Klara Briknarova, Jonathan K. Hilmer, Navid Movahed, Brian Bothner, John P. Sumida, Gregory G. Tall, Stephen R. Sprang Aug 2011

The Nucleotide Exchange Factor Ric-8a Is A Chaperone For The Conformationally Dynamic Nucleotide-Free State Of G Alpha I1, Celestine J. Thomas, Klara Briknarova, Jonathan K. Hilmer, Navid Movahed, Brian Bothner, John P. Sumida, Gregory G. Tall, Stephen R. Sprang

Chemistry and Biochemistry Faculty Publications

Heterotrimeric G protein alpha subunits are activated upon exchange of GDP for GTP at the nucleotide binding site of G alpha, catalyzed by guanine nucleotide exchange factors (GEFs). In addition to transmembrane G protein-coupled receptors (GPCRs), which act on G protein heterotrimers, members of the family cytosolic proteins typified by mammalian Ric-8A are GEFs for Gi/q/12/13-class G alpha subunits. Ric-8A binds to G alpha.GDP, resulting in the release of GDP. The Ric-8A complex with nucleotide-free G alpha i1 is stable, but dissociates upon binding of GTP to G alpha i1. To gain insight into the mechanism ...


Serum- And Glucocorticoid-Induced Kinase 3 In Recycling Endosomes Mediates Acute Activation Of Na+/H+ Exchanger Nhe3 By Glucocorticoids, Peijian He, Sei-Jung Lee, Songbai Lin, Ursula Seidler, Florian Lang, Geza Fejes-Toth, Aniko Naray-Fejes-Toth, C. Chris Yun Aug 2011

Serum- And Glucocorticoid-Induced Kinase 3 In Recycling Endosomes Mediates Acute Activation Of Na+/H+ Exchanger Nhe3 By Glucocorticoids, Peijian He, Sei-Jung Lee, Songbai Lin, Ursula Seidler, Florian Lang, Geza Fejes-Toth, Aniko Naray-Fejes-Toth, C. Chris Yun

Open Dartmouth: Faculty Open Access Scholarship

Na(+)/H(+) exchanger 3 (NHE3) is the major Na(+) transporter in the intestine. Serum- and glucocorticoid-induced kinase (SGK) 1 interacts with NHE regulatory factor 2 (NHERF2) and mediates activation of NHE3 by dexamethasone (Dex) in cultured epithelial cells. In this study, we compared short-term regulation of NHE3 by Dex in SGK1-null and NHERF2-null mice. In comparison to wild-type mice, loss of SGK1 or NHERF2 significantly attenuated regulation of NHE3 by Dex but did not completely obliterate the effect. We show that transfection of SGK2 or SGK3 in PS120 cells resulted in robust activation of NHE3 by Dex. However, unlike SGK1 ...


Forward Osmosis Bag: Ground Testing The Prospect Of Using Alternative Water Sources For Drinking Water, Michaela Marie Brant, Ariella Yendler, Mona Hammoudeh, Michael T. Flynn Aug 2011

Forward Osmosis Bag: Ground Testing The Prospect Of Using Alternative Water Sources For Drinking Water, Michaela Marie Brant, Ariella Yendler, Mona Hammoudeh, Michael T. Flynn

STAR (STEM Teacher and Researcher) Presentations

On the STS-135 Space Shuttle mission, to be launched July 8, 2011, a forward osmosis bag (FOB) study will be conducted. At NASA Ames this summer, the ground truth testing is being conducted for results comparisons. The FOB technology is derived from a commercial product, the X-Pack water filter. Forward osmosis operates by utilizing an established concentration gradient across a semi-permeable membrane to move water molecules from one side of the membrane to the other. This concept is exploited to harvest drinking water from grey water sources such as urine, sea water, or vehicle water. In this experiment, potassium chloride ...


Discovery Of An Apoptosis Inducing Ligand For Burkitt Lymphoma, Carolyn Laymon, Kyla Bradylong, Mary Saunders, David Olivos, Kit Lam Aug 2011

Discovery Of An Apoptosis Inducing Ligand For Burkitt Lymphoma, Carolyn Laymon, Kyla Bradylong, Mary Saunders, David Olivos, Kit Lam

STAR (STEM Teacher and Researcher) Presentations

One-bead two-compound (OB2C) combinatorial chemistry libraries enable the discovery of novel synthetic compounds which can be used to evoke specific signaling response in cells. The library configuration is composed of a fixed known cell adhesion ligand and a random chemical library displayed on the surface of Tentagel beads. The cell adhesion ligand binds to specific receptors located on the surface of cells enabling the random immobilized chemical molecules on each bead resin bead to evoke specific cellular responses such as apoptosis or cell death. To validate this concept, a OB2C combinatorial library comprised of an α4β1 integrin targeting ligand, LLP2A ...


Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley Aug 2011

Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley

STAR (STEM Teacher and Researcher) Presentations

Salmonids, such as Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), are a staple economic, recreational, tribal, and environmental resource, yet many populations are unsustainable. This study was part of a broad scale effort to monitor the impact of downstream migration obstacles on juvenile salmonid health and survival, which is an essential step towards increasing Smolt-to-Adult Return ratios (SARs). The objective of this study was to determine if juvenile Chinook salmon and steelhead exhibit differing quantities of alphaII-Spectrin Breakdown Products (SBDPs) over two consecutive spring migration periods, indicative of neurogenesis rate and/or biological response to head injury. AlphaII-Spectrin is ...


Extracellular Atp Acts On P2y2 Purinergic Receptors To Facilitate Hiv-1 Infection, Claire Séror, Marie-Therese Melki, Frederic Subra, Syed Qasim Raza, Marlene Bras, Hela Saïdi, Roberta Nardacci, Laurent Voisin, Audrey Paoletti, Frederic Law, Isabelle Martins, Alessandra Amendola, Ali A. Abdul-Sater, Fabiola Ciccosanti, Olivier Delelis, Florence Niedergang, Sylvain Thierry, Najwane Said-Sadier, Christophe Lamaze, Didier Métivier, Jerome Estaquier, Gian Maria Fimia, Laura Falasca, Rita Casetti, Nazanine Modjtahedi, Jean M. Kanellopoulos, Jean-Francois Mouscadet, David M. Ojcius, Mauro Piacentini, Marie-Lise Gougeon, Guido Kroemer, Jean-Luc Perfetini Aug 2011

Extracellular Atp Acts On P2y2 Purinergic Receptors To Facilitate Hiv-1 Infection, Claire Séror, Marie-Therese Melki, Frederic Subra, Syed Qasim Raza, Marlene Bras, Hela Saïdi, Roberta Nardacci, Laurent Voisin, Audrey Paoletti, Frederic Law, Isabelle Martins, Alessandra Amendola, Ali A. Abdul-Sater, Fabiola Ciccosanti, Olivier Delelis, Florence Niedergang, Sylvain Thierry, Najwane Said-Sadier, Christophe Lamaze, Didier Métivier, Jerome Estaquier, Gian Maria Fimia, Laura Falasca, Rita Casetti, Nazanine Modjtahedi, Jean M. Kanellopoulos, Jean-Francois Mouscadet, David M. Ojcius, Mauro Piacentini, Marie-Lise Gougeon, Guido Kroemer, Jean-Luc Perfetini

Dugoni School of Dentistry Faculty Articles

Extracellular adenosine triphosphate (ATP) can activate purinergic receptors of the plasma membrane and modulate multiple cellular functions. We report that ATP is released from HIV-1 target cells through pannexin-1 channels upon interaction between the HIV-1 envelope protein and specific target cell receptors. Extracellular ATP then acts on purinergic receptors, including P2Y2, to activate proline-rich tyrosine kinase 2 (Pyk2) kinase and transient plasma membrane depolarization, which in turn stimulate fusion between Env-expressing membranes and membranes containing CD4 plus appropriate chemokine co-receptors. Inhibition of any of the constituents of this cascade (pannexin-1, ATP, P2Y2, and Pyk2) impairs the replication of HIV-1 mutant ...


Computational Identification Of Protein Catalytic Sites: Tests, Validation, Dan Kirshner, Jerome Nilmeier, Felice Lightstone Aug 2011

Computational Identification Of Protein Catalytic Sites: Tests, Validation, Dan Kirshner, Jerome Nilmeier, Felice Lightstone

STAR (STEM Teacher and Researcher) Presentations

This project is one element of the analysis “pipeline” to characterize an organism that previously has not been well-studied. Once a protein of unknown structure has been computationally modeled (based on its sequence similarity to proteins with solved structures), then catalytic sites are identified on the model by comparison to a library of known sites. This work tested the identification algorithms with a set of proteins that have known structures and catalytic sites.


Gata-Family Transcription Factors In Magnaporthe Oryzae, Cristian F. Quispe Aug 2011

Gata-Family Transcription Factors In Magnaporthe Oryzae, Cristian F. Quispe

Theses, Dissertations, and Student Research in Agronomy and Horticulture

The filamentous fungus, Magnaporthe oryzae, responsible for blast rice disease, destroys around 10-30% of the rice crop annually. Infection begins when the specialized infection structure, the appressorium, generates enormous internal turgor pressure through the accumulation of glycerol. This turgor acts on a penetration peg emerging at the base of the cell, causing it to breach the leaf surface allowing its infection.

The enzyme trehalose-6- phosphate synthase (Tps1) is a central regulator of the transition from appressorium development to infectious hyphal growth. In the first chapter we show that initiation of rice blast disease requires a regulatory mechanism involving an NADPH ...