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Full-Text Articles in Life Sciences
Molecular Mechanism For Depolarization-Induced Modulation Of Kv Channel Closure, Alain J. Labro, Jerome J. Lacroix, Carlos A. Villalba-Galea, Dirk J. Snyders, Francisco Bezanilla
Molecular Mechanism For Depolarization-Induced Modulation Of Kv Channel Closure, Alain J. Labro, Jerome J. Lacroix, Carlos A. Villalba-Galea, Dirk J. Snyders, Francisco Bezanilla
School of Pharmacy Faculty Articles
Voltage-dependent potassium (Kv) channels provide the repolarizing power that shapes the action potential duration and helps control the firing frequency of neurons. The K(+) permeation through the channel pore is controlled by an intracellularly located bundle-crossing (BC) gate that communicates with the voltage-sensing domains (VSDs). During prolonged membrane depolarizations, most Kv channels display C-type inactivation that halts K(+) conduction through constriction of the K(+) selectivity filter. Besides triggering C-type inactivation, we show that in Shaker and Kv1.2 channels (expressed in Xenopus laevis oocytes), prolonged membrane depolarizations also slow down the kinetics of VSD deactivation and BC gate closure during the …
A Human Phospholipid Phosphatase Activated By A Transmembrane Control Module, Christian R. Halaszovich, Michael G. Leitner, Angeliki Mavrantoni, Audrey Le, Ludivine Frezza, Anja Feuer, Daniela N. Schreiber, Carlos A. Villalba-Galea, Dominik Oliver
A Human Phospholipid Phosphatase Activated By A Transmembrane Control Module, Christian R. Halaszovich, Michael G. Leitner, Angeliki Mavrantoni, Audrey Le, Ludivine Frezza, Anja Feuer, Daniela N. Schreiber, Carlos A. Villalba-Galea, Dominik Oliver
School of Pharmacy Faculty Articles
In voltage-sensitive phosphatases (VSPs), a transmembrane voltage sensor domain (VSD) controls an intracellular phosphoinositide phosphatase domain, thereby enabling immediate initiation of intracellular signals by membrane depolarization. The existence of such a mechanism in mammals has remained elusive, despite the presence of VSP-homologous proteins in mammalian cells, in particular in sperm precursor cells. Here we demonstrate activation of a human VSP (hVSP1/TPIP) by an intramolecular switch. By engineering a chimeric hVSP1 with enhanced plasma membrane targeting containing the VSD of a prototypic invertebrate VSP, we show that hVSP1 is a phosphoinositide-5-phosphatase whose predominant substrate is PI(4,5)P(2). In the chimera, enzymatic activity …
Cysteine 904 Is Required For Maximal Insulin Degrading Enzyme Activity And Polyanion Activation, Eun Suk Song, Manana Melikishvili, Michael G. Fried, Maria A. Juliano, Luiz Juliano, David W. Rodgers, Louis B. Hersh
Cysteine 904 Is Required For Maximal Insulin Degrading Enzyme Activity And Polyanion Activation, Eun Suk Song, Manana Melikishvili, Michael G. Fried, Maria A. Juliano, Luiz Juliano, David W. Rodgers, Louis B. Hersh
Molecular and Cellular Biochemistry Faculty Publications
Cysteine residues in insulin degrading enzyme have been reported as non-critical for its activity. We found that converting the twelve cysteine residues in rat insulin degrading enzyme (IDE) to serines resulted in a cysteine-free form of the enzyme with reduced activity and decreased activation by polyanions. Mutation of each cysteine residue individually revealed cysteine 904 as the key residue required for maximal activity and polyanion activation, although other cysteines affect polyanion binding to a lesser extent. Based on the structure of IDE, Asn 575 was identified as a potential hydrogen bond partner for Cys904 and mutation of this residue also …
Endogenous Inhibitor Proteins That Connect Ser/Thr Kinases And Phosphatases In Cell Signaling., Masumi Eto, David L Brautigan
Endogenous Inhibitor Proteins That Connect Ser/Thr Kinases And Phosphatases In Cell Signaling., Masumi Eto, David L Brautigan
Department of Molecular Physiology and Biophysics Faculty Papers
Protein phosphatase activity acts as a primary determinant of the extent and duration of phosphorylation of cellular proteins in response to physiological stimuli. Ser/Thr protein phosphatase-1 (PP1) belongs to the PPP superfamily, and is associated with regulatory subunits that confer substrate specificity, allosteric regulation, and subcellular compartmentalization. In addition, all eukaryotic cells contain multiple heat-stable proteins that originally were thought to inhibit phosphatase catalytic subunits released from the regulatory subunits, as a fail-safe mechanism. However, discovery of C-kinase-activated PP1 inhibitor, Mr of 17 kDa (CPI-17) required fresh thinking about the endogenous inhibitors as specific regulators of particular phosphatase complexes, acting …
Role Of Sequence And Structure Of The Hendra Fusion Protein Fusion Peptide In Membrane Fusion, Everett Clinton Smith, Sonia M. Gregory, Lukas K. Tamm, Trevor P. Creamer, Rebecca Ellis Dutch
Role Of Sequence And Structure Of The Hendra Fusion Protein Fusion Peptide In Membrane Fusion, Everett Clinton Smith, Sonia M. Gregory, Lukas K. Tamm, Trevor P. Creamer, Rebecca Ellis Dutch
Molecular and Cellular Biochemistry Faculty Publications
Viral fusion proteins are intriguing molecular machines that undergo drastic conformational changes to facilitate virus-cell membrane fusion. During fusion a hydrophobic region of the protein, termed the fusion peptide (FP), is inserted into the target host cell membrane, with subsequent conformational changes culminating in membrane merger. Class I fusion proteins contain FPs between 20 and 30 amino acids in length that are highly conserved within viral families but not between. To examine the sequence dependence of the Hendra virus (HeV) fusion (F) protein FP, the first eight amino acids were mutated first as double, then single, alanine mutants. Mutation of …
Myxobacteria Versus Sponge-Derived Alkaloids: The Bengamide Family Identified As Potent Immune Modulating Agents By Scrutiny Of Lc-Ms/Elsd Libraries., Tyler A. Johnson, Johann Sohn, Yvette M. Vaske, Kimberly N. White, Tanya L. Cohen, Helene C. Vervoort, Karen Tenney, Frederick A. Valeriote, Leonard F. Bjeldanes, Phillip Crews
Myxobacteria Versus Sponge-Derived Alkaloids: The Bengamide Family Identified As Potent Immune Modulating Agents By Scrutiny Of Lc-Ms/Elsd Libraries., Tyler A. Johnson, Johann Sohn, Yvette M. Vaske, Kimberly N. White, Tanya L. Cohen, Helene C. Vervoort, Karen Tenney, Frederick A. Valeriote, Leonard F. Bjeldanes, Phillip Crews
Natural Sciences and Mathematics | Faculty Scholarship
A nuclear factor-κB (NF-κB) luciferase assay has been employed to identify the bengamides, previously known for their anti-tumor activity, as a new class of immune modulators. A unique element of this study was that the bengamide analogs were isolated from two disparate sources, Myxococcus virescens (bacterium) and Jaspis coriacea (sponge). Comparative LC-MS/ELSD and NMR analysis facilitated the isolation of M. viriscens derived samples of bengamide E (8) and two congeners, bengamide E' (13) and F' (14) each isolated as an insperable mixture of diastereomers. Additional compounds drawn from the UC, Santa Cruz repository allowed expansion of the structure activity relationship …
Shoc2 Is Targeted To Late Endosomes And Required For Erk1/2 Activation In Egf-Stimulated Cells, Emilia Galperin, Lina Abdelmoti, Alexander Sorkin
Shoc2 Is Targeted To Late Endosomes And Required For Erk1/2 Activation In Egf-Stimulated Cells, Emilia Galperin, Lina Abdelmoti, Alexander Sorkin
Molecular and Cellular Biochemistry Faculty Publications
Shoc2 is the putative scaffold protein that interacts with RAS and RAF, and positively regulates signaling to extracellular signal-regulated protein kinases 1 and 2 (ERK1/2). To elucidate the mechanism by which Shoc2 regulates ERK1/2 activation by the epidermal growth factor (EGF) receptor (EGFR), we studied subcellular localization of Shoc2. Upon EGFR activation, endogenous Shoc2 and red fluorescent protein tagged Shoc2 were translocated from the cytosol to a subset of late endosomes containing Rab7. The endosomal recruitment of Shoc2 was blocked by overexpression of a GDP-bound H-RAS (N17S) mutant and RNAi knockdown of clathrin, suggesting the requirement of RAS activity and …
Prostate Cancer-Specific And Potent Antitumor Effect Of A Dd3-Controlled Oncolytic Virus Harboring The Pten Gene, Miao Ding, Xin Cao, Hai-Neng Xu, Jun-Kai Fan, Hong-Ling Huang, Dong-Qin Yang, Yu-Hua Li, Jian Wang, Runsheng Li, Xin-Yuan Liu
Prostate Cancer-Specific And Potent Antitumor Effect Of A Dd3-Controlled Oncolytic Virus Harboring The Pten Gene, Miao Ding, Xin Cao, Hai-Neng Xu, Jun-Kai Fan, Hong-Ling Huang, Dong-Qin Yang, Yu-Hua Li, Jian Wang, Runsheng Li, Xin-Yuan Liu
Molecular and Cellular Biochemistry Faculty Publications
Prostate cancer is a major health problem for men in Western societies. Here we report a Prostate Cancer-Specific Targeting Gene-Viro-Therapy (CTGVT-PCa), in which PTEN was inserted into a DD3-controlled oncolytic viral vector (OV) to form Ad.DD3.E1A.E1B(Δ55)-(PTEN) or, briefly, Ad.DD3.D55-PTEN. The woodchuck post-transcriptional element (WPRE) was also introduced at the downstream of the E1A coding sequence, resulting in much higher expression of the E1A gene. DD3 is one of the most prostate cancer-specific genes and has been used as a clinical bio-diagnostic marker. PTEN is frequently inactivated in primary prostate cancers, which is crucial for prostate cancer progression. Therefore, the Ad.DD3.D55-PTEN …
G9a Interacts With Snail And Is Critical For Snail-Mediated E-Cadherin Repression In Human Breast Cancer, Chenfang Dong, Yadi Wu, Jun Yao, Yifan Wang, Yinhua Yu, Piotr G. Rychahou, B. Mark Evers, Binhua P. Zhou
G9a Interacts With Snail And Is Critical For Snail-Mediated E-Cadherin Repression In Human Breast Cancer, Chenfang Dong, Yadi Wu, Jun Yao, Yifan Wang, Yinhua Yu, Piotr G. Rychahou, B. Mark Evers, Binhua P. Zhou
Molecular and Cellular Biochemistry Faculty Publications
Breast cancers are highly heterogeneous but can be grouped into subtypes based on several criteria, including level of expression of certain markers. Claudin-low breast cancer (CLBC) is associated with early metastasis and resistance to chemotherapy, while gene profiling indicates it is characterized by the expression of markers of epithelial-mesenchymal transition (EMT) - a phenotypic conversion linked with metastasis. Although the epigenetic program controlling the phenotypic and cellular plasticity of EMT remains unclear, one contributor may be methylation of the E-cadherin promoter, resulting in decreased E-cadherin expression, a hallmark of EMT. Indeed, reduced E-cadherin often occurs in CLBC and may contribute …
Glycosylation Of Human Cyclooxygenase-2 (Cox-2) Decreases The Efficacy Of Certain Cox-2 Inhibitors., Mary B. Sevigny, Kamara Graham, Esmeralda Ponce, Maggie Louie, Kylie Mitchell
Glycosylation Of Human Cyclooxygenase-2 (Cox-2) Decreases The Efficacy Of Certain Cox-2 Inhibitors., Mary B. Sevigny, Kamara Graham, Esmeralda Ponce, Maggie Louie, Kylie Mitchell
Natural Sciences and Mathematics | Faculty Scholarship
Prostanoids play an important role in a variety of physiological and pathophysiological processes including inflammation and cancer. The rate-limiting step in the prostanoid biosynthesis pathway is catalyzed by cyclooxygenase-2 (COX-2). COX-2 exists as two glycoforms, 72 and 74 kDa, the latter resulting from an additional glycosylation at Asn(580). In this study, Asn(580) was mutated, and the mutant and wild-type COX-2 genes were expressed in COS-1 cells to determine how glycosylation affects the inhibition of COX-2 activity by aspirin, flurbiprofen, ibuprofen, celecoxib, and etoricoxib. Results indicate that certain inhibitors were 2-5 times more effective at inhibiting COX-2 activity when the glycosylation …
Glycoinositolphospholipids From Leishmania Braziliensis And L. Infantum: Modulation Of Innate Immune System And Variations In Carbohydrate Structure, Rafael Ramiro Assis, Izabela Coimbra Ibraim, Fátima Soares Noronha, Salvatore J. Turco, Rodrigo Pedro Soares
Glycoinositolphospholipids From Leishmania Braziliensis And L. Infantum: Modulation Of Innate Immune System And Variations In Carbohydrate Structure, Rafael Ramiro Assis, Izabela Coimbra Ibraim, Fátima Soares Noronha, Salvatore J. Turco, Rodrigo Pedro Soares
Molecular and Cellular Biochemistry Faculty Publications
The essential role of the lipophosphoglycan (LPG) of Leishmania in innate immune response has been extensively reported. However, information about the role of the LPG-related glycoinositolphospholipids (GIPLs) is limited, especially with respect to the New World species of Leishmania. GIPLs are low molecular weight molecules covering the parasite surface and are similar to LPG in sharing a common lipid backbone and a glycan motif containing up to 7 sugars. Critical aspects of their structure and functions are still obscure in the interaction with the vertebrate host. In this study, we evaluated the role of those molecules in two medically important …
Auf1/Hnrnp D Represses Expression Of Vegf In Macrophages, Abigail Fellows, Mary E. Griffin, Brenda L. Petrella, Lihui Zhong, Fatemeh P. Parvin-Nejad, Roy Fava, Peter Morganelli, R. Brooks Robey, Ralph C. Nichols
Auf1/Hnrnp D Represses Expression Of Vegf In Macrophages, Abigail Fellows, Mary E. Griffin, Brenda L. Petrella, Lihui Zhong, Fatemeh P. Parvin-Nejad, Roy Fava, Peter Morganelli, R. Brooks Robey, Ralph C. Nichols
Dartmouth Scholarship
Vascular endothelial growth factor (VEGF) is a regulator of vascularization in development and is a key growth factor in tissue repair. In disease, VEGF contributes to vascularization of solid tumors and arthritic joints. This study examines the role of the mRNA-binding protein AUF1/heterogeneous nuclear ribonucleoprotein D (AUF1) in VEGF gene expression. We show that overexpression of AUF1 in mouse macrophage-like RAW-264.7 cells suppresses endogenous VEGF protein levels. To study 3′ untranslated region (UTR)–mediated regulation, we introduced the 3′ UTR of VEGF mRNA into a luciferase reporter gene. Coexpression of AUF1 represses VEGF-3′ UTR reporter expression in RAW-264.7 cells and in …
Dual Recognition Of The Ribosome And The Signal Recognition Particle By The Srp Receptor During Protein Targeting To The Endoplasmic Reticulum, Elisabet C. Mandon, Ying Jiang, Reid Gilmore
Dual Recognition Of The Ribosome And The Signal Recognition Particle By The Srp Receptor During Protein Targeting To The Endoplasmic Reticulum, Elisabet C. Mandon, Ying Jiang, Reid Gilmore
Elisabet Mandon
We have analyzed the interactions between the signal recognition particle (SRP), the SRP receptor (SR), and the ribosome using GTPase assays, biosensor experiments, and ribosome binding assays. Possible mechanisms that could contribute to an enhanced affinity between the SR and the SRP-ribosome nascent chain complex to promote protein translocation under physiological ionic strength conditions have been explored. Ribosomes or 60S large ribosomal subunits activate the GTPase cycle of SRP54 and SRalpha by providing a platform for assembly of the SRP-SR complex. Biosensor experiments revealed high-affinity, saturable binding of ribosomes or large ribosomal subunits to the SR. Remarkably, the SR has …
Usp8 Promotes Smoothened Signaling By Preventing Its Ubiquitination And Changing Its Subcellular Localization, Ruohan Xia, Hongge Jia, Junkai Fan, Yajuan Liu, Jianhang Jia
Usp8 Promotes Smoothened Signaling By Preventing Its Ubiquitination And Changing Its Subcellular Localization, Ruohan Xia, Hongge Jia, Junkai Fan, Yajuan Liu, Jianhang Jia
Molecular and Cellular Biochemistry Faculty Publications
The seven transmembrane protein Smoothened (Smo) is a critical component of the Hedgehog (Hh) signaling pathway and is regulated by phosphorylation, dimerization, and cell-surface accumulation upon Hh stimulation. However, it is not clear how Hh regulates Smo accumulation on the cell surface or how Hh regulates the intracellular trafficking of Smo. In addition, little is known about whether ubiquitination is involved in Smo regulation. In this study, we demonstrate that Smo is multi-monoubiquitinated and that Smo ubiquitination is inhibited by Hh and by phosphorylation. Using an in vivo RNAi screen, we identified ubiquitin-specific protease 8 (USP8) as a deubiquitinase that …
Methamphetamine Administration Targets Multiple Immune Subsets And Induces Phenotypic Alterations Suggestive Of Immunosuppression., Robert Z. Harms, Brenda M. Morsey, Craig W. Boyer, Howard S. Fox, Nora E. Sarvetnick
Methamphetamine Administration Targets Multiple Immune Subsets And Induces Phenotypic Alterations Suggestive Of Immunosuppression., Robert Z. Harms, Brenda M. Morsey, Craig W. Boyer, Howard S. Fox, Nora E. Sarvetnick
Journal Articles: Regenerative Medicine
Methamphetamine (Meth) is a widely abused stimulant and its users are at increased risk for multiple infectious diseases. To determine the impact of meth on the immune system, we utilized a murine model that simulates the process of meth consumption in a typical addict. Our phenotypic analysis of leukocytes from this dose escalation model revealed that meth affected key immune subsets. Meth administration led to a decrease in abundance of natural killer (NK) cells and the remaining NK cells possessed a phenotype suggesting reduced responsiveness. Dendritic cells (DCs) and Gr-1(high) monocytes/macrophages were also decreased in abundance while Gr-1(low) monocytes/macrophages appear …
Genetic Control Of A Central Pattern Generator: Rhythmic Oromotor Movement In Mice Is Controlled By A Major Locus Near Atp1a2, Steven J. St. John, John D. Boughter Jr, Megan K. Mulligan, Kenichi Tokita, Lu Lu, Detlef H. Heck, Robert W. Williams
Genetic Control Of A Central Pattern Generator: Rhythmic Oromotor Movement In Mice Is Controlled By A Major Locus Near Atp1a2, Steven J. St. John, John D. Boughter Jr, Megan K. Mulligan, Kenichi Tokita, Lu Lu, Detlef H. Heck, Robert W. Williams
Faculty Publications
calreticulin, Animals, Chromosome Mapping, Mammalian Chromosomes, Gene Expression Regulation, Genetic Linkage, Genome-Wide Association Study. Inbred C57BL Mice, Inbred DBA Mice, Quantitative Trait Loci, Sodium-Potassium-Exchanging ATPase/genetics, Atp1a2 protein, Sodium-Potassium-Exchanging ATPase, feeding behavior, drinking behavior, mice, central pattern generator, genetic control
Dimerization And Heme Binding Are Conserved In Amphibian And Starfish Homologues Of The Microrna Processing Protein Dgcr8., Rachel Senturia, Arthur Laganowsky, Ian Barr, Brooke D. Scheidemantle, Feng Guo
Dimerization And Heme Binding Are Conserved In Amphibian And Starfish Homologues Of The Microrna Processing Protein Dgcr8., Rachel Senturia, Arthur Laganowsky, Ian Barr, Brooke D. Scheidemantle, Feng Guo
Natural Sciences and Mathematics | Faculty Scholarship
Human DiGeorge Critical Region 8 (DGCR8) is an essential microRNA (miRNA) processing factor that is activated via direct interaction with Fe(III) heme. In order for DGCR8 to bind heme, it must dimerize using a dimerization domain embedded within its heme-binding domain (HBD). We previously reported a crystal structure of the dimerization domain from human DGCR8, which demonstrated how dimerization results in the formation of a surface important for association with heme. Here, in an attempt to crystallize the HBD, we search for DGCR8 homologues and show that DGCR8 from Patiria miniata (bat star) also binds heme. The extinction coefficients (ε) …