Biochemistry, Biophysics, and Structural Biology Commons^™

Axonal Blockage With Microscopic Magnetic Stimulation, Hui Ye

Biology: Faculty Publications and Other Works

Numerous neurological dysfunctions are characterized by undesirable nerve activity. By providing reversible nerve blockage, electric stimulation with an implanted electrode holds promise in the treatment of these conditions. However, there are several limitations to its application, including poor bio-compatibility and decreased efficacy during chronic implantation. A magnetic coil of miniature size can mitigate some of these problems, by coating it with biocompatible material for chronic implantation. However, it is unknown if miniature coils could be effective in axonal blockage and, if so, what the underlying mechanisms are. Here we demonstrate that a submillimeter magnetic coil can reversibly block action potentials …

Antioxidant Carbon Nanoparticles Inhibit Fibroblast-Like Synoviocyte Invasiveness And Reduce Disease Severity In A Rat Model Of Rheumatoid Arthritis, Mark R Tanner, Redwan Huq, William K A Sikkema, Lizanne G Nilewski, Nejla Yosef, Cody Schmitt, Carlos P Flores-Suarez, Arielle Raugh, Teresina Laragione, Pércio S Gulko, James M Tour, Christine Beeton

Faculty, Staff and Students Publications

Reactive oxygen species have been involved in the pathogenesis of rheumatoid arthritis (RA). Our goal was to determine the effects of selectively scavenging superoxide (O2•−) and hydroxyl radicals with antioxidant nanoparticles, called poly(ethylene glycol)-functionalized hydrophilic carbon clusters (PEG-HCCs), on the pathogenic functions of fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) and on the progression of an animal model of RA. We used human FLS from patients with RA to determine PEG-HCC internalization and effects on FLS cytotoxicity, invasiveness, proliferation, and production of proteases. We used the pristane-induced arthritis (PIA) rat model of RA to assess the benefits of …

Distribution Of Microglial Phenotypes As A Function Of Age And Alzheimer's Disease Neuropathology In The Brains Of People With Down Syndrome, Alessandra C. Martini, Alex M. Helman, Katie L. Mccarty, Ira T. Lott, Eric Doran, Frederick A. Schmitt, Elizabeth Head

Sanders-Brown Center on Aging Faculty Publications

Introduction: Microglial cells play an important role in the development of Alzheimer's disease (AD). People with Down syndrome (DS) inevitably develop AD neuropathology (DSAD) by 40 years of age. We characterized the distribution of different microglial phenotypes in the brains of people with DS and DSAD.

Methods: Autopsy tissue from the posterior cingulate cortex (PCC) from people with DS, DSAD, and neurotypical controls was immunostained with the microglial marker Iba1 to assess five microglia morphological types.

Results: Individuals with DS have more hypertrophic microglial cells in their white matter. In the gray matter, individuals with DSAD had significantly fewer ramified …

Adaptive Thermogenesis Enhances The Life-Threatening Response To Heat In Mice With An Ryr1 Mutation, Hui J Wang, Chang Seok Lee, Rachel Sue Zhen Yee, Linda Groom, Inbar Friedman, Lyle Babcock, Dimitra K Georgiou, Jin Hong, Amy D Hanna, Joseph Recio, Jong Min Choi, Ting Chang, Nadia H Agha, Jonathan Romero, Poonam Sarkar, Nicol Voermans, M Waleed Gaber, Sung Yun Jung, Matthew L Baker, Robia G Pautler, Robert T Dirksen, Sheila Riazi, Susan L Hamilton

Faculty, Staff and Students Publications

Mutations in the skeletal muscle Ca2+ release channel, the type 1 ryanodine receptor (RYR1), cause malignant hyperthermia susceptibility (MHS) and a life-threatening sensitivity to heat, which is most severe in children. Mice with an MHS-associated mutation in Ryr1 (Y524S, YS) display lethal muscle contractures in response to heat. Here we show that the heat response in the YS mice is exacerbated by brown fat adaptive thermogenesis. In addition, the YS mice have more brown adipose tissue thermogenic capacity than their littermate controls. Blood lactate levels are elevated in both heat-sensitive MHS patients with RYR1 mutations and YS mice due to …

Minimal Structural Elements Required For Midline Repulsive Signaling And Regulation Of Drosophila Robo1, Haley E. Brown, Timonthy A. Evans

Biological Sciences Faculty Publications and Presentations

The Roundabout (Robo) family of axon guidance receptors has a conserved ectodomain arrangement of five immunoglobulin-like (Ig) domains plus three fibronectin type III (Fn) repeats. Based on the strong evolutionary conservation of this domain structure among Robo receptors, as well as in vitro structural and domain-domain interaction studies of Robo family members, this ectodomain arrangement is predicted to be important for Robo receptor signaling in response to Slit ligands. Here, we define the minimal ectodomain structure required for Slit binding and midline repulsive signaling in vivo by Drosophila Robo1. We find that the majority of the Robo1 ectodomain is dispensable …

Low-Shot Deep Learning Of Diabetic Retinopathy With Potential Applications To Address Artificial Intelligence Bias In Retinal Diagnostics And Rare Ophthalmic Diseases, Philippe Burlina, William Paul, Philip Mathew, Neil Joshi, Katia D Pacheco, Neil M Bressler

Faculty, Staff and Students Publications

IMPORTANCE: Recent studies have demonstrated the successful application of artificial intelligence (AI) for automated retinal disease diagnostics but have not addressed a fundamental challenge for deep learning systems: the current need for large, criterion standard-annotated retinal data sets for training. Low-shot learning algorithms, aiming to learn from a relatively low number of training data, may be beneficial for clinical situations involving rare retinal diseases or when addressing potential bias resulting from data that may not adequately represent certain groups for training, such as individuals older than 85 years.

OBJECTIVE: To evaluate whether low-shot deep learning methods are beneficial when using …

Mir-30a Targets Gene Networks That Promote Browning Of Human And Mouse Adipocytes, Pradip K Saha, Mark P Hamilton, Kimal Rajapakshe, Vasanta Putluri, Jessica B Felix, Peter Masschelin, Aaron R Cox, Mandeep Bajaj, Nagireddy Putluri, Cristian Coarfa, Sean M Hartig

Faculty, Staff and Students Publications

MicroRNA-30a (miR-30a) impacts adipocyte function, and its expression in white adipose tissue (WAT) correlates with insulin sensitivity in obesity. Bioinformatic analysis demonstrates that miR-30a expression contributes to 2% of all miRNA expression in human tissues. However, molecular mechanisms of miR-30a function in fat cells remain unclear. Here, we expanded our understanding of how miR-30a expression contributes to antidiabetic peroxisome proliferator-activated receptor-γ (PPARγ) agonist activity and metabolic functions in adipocytes. We found that WAT isolated from diabetic patients shows reduced miR-30a levels and diminished expression of the canonical PPARγ target genes ADIPOQ and FABP4 relative to lean counterparts. In human adipocytes, …

Versatile Phenotype-Activated Cell Sorting, Jihwan Lee, Zhuohe Liu, Peter H Suzuki, John F Ahrens, Shujuan Lai, Xiaoyu Lu, Sihui Guan, François St-Pierre

Faculty, Staff and Students Publications

Unraveling the genetic and epigenetic determinants of phenotypes is critical for understanding and re-engineering biology and would benefit from improved methods to separate cells based on phenotypes. Here, we report SPOTlight, a versatile high-throughput technique to isolate individual yeast or human cells with unique spatiotemporal profiles from heterogeneous populations. SPOTlight relies on imaging visual phenotypes by microscopy, precise optical tagging of single target cells, and retrieval of tagged cells by fluorescence-activated cell sorting. To illustrate SPOTlight's ability to screen cells based on temporal properties, we chose to develop a photostable yellow fluorescent protein for extended imaging experiments. We screened 3 …

An Autism-Linked Missense Mutation In Shank3 Reveals The Modularity Of Shank3 Function, Li Wang, Kaifang Pang, Kihoon Han, Carolyn J Adamski, Wei Wang, Lingjie He, Jason K Lai, Vitaliy V Bondar, Joseph G Duman, Ronald Richman, Kimberley F Tolias, Patrick Barth, Timothy Palzkill, Zhandong Liu, J Lloyd Holder, Huda Y Zoghbi

Faculty, Staff and Students Publications

Genome sequencing has revealed an increasing number of genetic variations that are associated with neuropsychiatric disorders. Frequently, studies limit their focus to likely gene-disrupting mutations because they are relatively easy to interpret. Missense variants, instead, have often been undervalued. However, some missense variants can be informative for developing a more profound understanding of disease pathogenesis and ultimately targeted therapies. Here we present an example of this by studying a missense variant in a well-known autism spectrum disorder (ASD) causing gene SHANK3. We analyzed Shank3's in vivo phosphorylation profile and identified S685 as one phosphorylation site where one ASD-linked variant has …

Ampk Regulation Of Raptor And Tsc2 Mediate Metformin Effects On Transcriptional Control Of Anabolism And Inflammation, Jeanine L Van Nostrand, Kristina Hellberg, En-Ching Luo, Eric L Van Nostrand, Alina Dayn, Jingting Yu, Maxim N Shokhirev, Yelena Dayn, Gene W Yeo, Reuben J Shaw

Faculty, Staff and Students Publications

Despite being the frontline therapy for type 2 diabetes, the mechanisms of action of the biguanide drug metformin are still being discovered. In particular, the detailed molecular interplays between the AMPK and the mTORC1 pathway in the hepatic benefits of metformin are still ill defined. Metformin-dependent activation of AMPK classically inhibits mTORC1 via TSC/RHEB, but several lines of evidence suggest additional mechanisms at play in metformin inhibition of mTORC1. Here we investigated the role of direct AMPK-mediated serine phosphorylation of RAPTOR in a new

Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

In soft matter, thermal energy causes molecules to continuously translate and rotate, even in crowded environments, thereby impacting the spatial organization and function of most molecular assemblies, such as lipid membranes. Directly measuring the orientation and spatial organization of large collections (>3000 molecules μm⁻²) of single molecules with nanoscale resolution remains elusive. In this paper, we utilize SMOLM, single‐molecule orientation localization microscopy, to directly measure the orientation spectra (3D orientation plus “wobble”) of lipophilic probes transiently bound to lipid membranes, revealing that Nile red's (NR) orientation spectra are extremely sensitive to membrane chemical composition. SMOLM images resolve …

When Patients Die: Patient Memorials And Group Reflection In An Internal Medicine Residency Program, Nicole Oakman, Jonathan Lim, Christine Bui, Holland Kaplan, Stephanie Sherman

Faculty, Staff and Students Publications

Patient death is a formative and emotional experience for physicians. Medical trainees are particularly susceptible to the emotional impact of patient death. However, few studies have examined how trainees process patient death. This study describes annual patient memorials organized at a large multisite academic graduate medical education program. Peer-led, 1-hour patient memorial services were organized for internal medicine residents, including large and small group reflection, a moment of silence, and collective art projects. At the conclusion of each memorial, participants completed a 10-question survey regarding their experience during the memorial and their prior experiences with patient death. Ninety-nine surveys were …

Tdp-43 Mediated Blood-Brain Barrier Permeability And Leukocyte Infiltration Promote Neurodegeneration In A Low-Grade Systemic Inflammation Mouse Model, Frank Zamudio, Anjanet R. Loon, Shayna Smeltzer, Khawla Benyamine, Nanda K. Navalpur Shanmugam, Nicholas J. F. Stewart, Daniel C. Lee, Kevin Nash, Maj-Linda B. Selenica

Sanders-Brown Center on Aging Faculty Publications

BACKGROUND: Neuronal cytoplasmic inclusions containing TAR DNA-binding protein 43 (TDP-43) are a neuropathological feature of several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Alzheimer's Disease (AD). Emerging evidence also indicates that systemic inflammation may be a contributor to the pathology progression of these neurodegenerative diseases.

METHODS: To investigate the role of systemic inflammation in the progression of neuronal TDP-43 pathology, AAV9 particles driven by the UCHL1 promoter were delivered to the frontal cortex of wild-type aged mice via intracranial injections to overexpress TDP-43 or green fluorescent protein (GFP) in corticospinal motor neurons. Animals were then subjected …

Atrial Myocyte Nlrp3/Camkii Nexus Forms A Substrate For Postoperative Atrial Fibrillation, Jordi Heijman, Azinwi Phina Muna, Tina Veleva, Cristina E Molina, Henry Sutanto, Marcel Tekook, Qiongling Wang, Issam H Abu-Taha, Marcel Gorka, Stephan Künzel, Ali El-Armouche, Hermann Reichenspurner, Markus Kamler, Viacheslav Nikolaev, Ursula Ravens, Na Li, Stanley Nattel, Xander H T Wehrens, Dobromir Dobrev

Faculty, Staff and Students Publications

RATIONALE: Postoperative atrial fibrillation (POAF) is a common and troublesome complication of cardiac surgery. POAF is generally believed to occur when postoperative triggers act on a preexisting vulnerable substrate, but the underlying cellular and molecular mechanisms are largely unknown.

OBJECTIVE: To identify cellular POAF mechanisms in right atrial samples from patients without a history of atrial fibrillation undergoing open-heart surgery.

METHODS AND RESULTS: Multicellular action potentials, membrane ion-currents (perforated patch-clamp), or simultaneous membrane-current (ruptured patch-clamp) and [Ca

CONCLUSIONS: Preexisting Ca

Loss Of Speg Inhibitory Phosphorylation Of Ryanodine Receptor Type-2 Promotes Atrial Fibrillation, Hannah M Campbell, Ann P Quick, Issam Abu-Taha, David Y Chiang, Carlos F Kramm, Tarah A Word, Sören Brandenburg, Mohit Hulsurkar, Katherina M Alsina, Hui-Bin Liu, Brian Martin, Dennis Uhlenkamp, Oliver M Moore, Satadru K Lahiri, Eleonora Corradini, Markus Kamler, Albert J R Heck, Stephan E Lehnart, Dobromir Dobrev, Xander H T Wehrens

Faculty, Staff and Students Publications

BACKGROUND: Enhanced diastolic calcium (Ca

METHODS: Western blotting was performed with right atrial biopsies from patients with paroxysmal AF. SPEG atrial knockout mice were generated using adeno-associated virus 9. In mice, AF inducibility was determined using intracardiac programmed electric stimulation, and diastolic Ca

RESULTS: Western blotting revealed decreased SPEG protein levels in atrial biopsies from patients with paroxysmal AF in comparison with patients in sinus rhythm. SPEG atrial-specific knockout mice exhibited increased susceptibility to pacing-induced AF by programmed electric stimulation and enhanced Ca

CONCLUSIONS: Unlike other kinases (PKA, CaMKII) that increase RyR2 activity, SPEG phosphorylation reduces RyR2-mediated sarcoplasmic reticulum Ca

Atom Identifiers Generated By A Neighborhood-Specific Graph Coloring Method Enable Compound Harmonization Across Metabolic Databases, Huan Jin, Joshua M. Mitchell, Hunter N. B. Moseley

Molecular and Cellular Biochemistry Faculty Publications

Metabolic flux analysis requires both a reliable metabolic model and reliable metabolic profiles in characterizing metabolic reprogramming. Advances in analytic methodologies enable production of high-quality metabolomics datasets capturing isotopic flux. However, useful metabolic models can be difficult to derive due to the lack of relatively complete atom-resolved metabolic networks for a variety of organisms, including human. Here, we developed a neighborhood-specific graph coloring method that creates unique identifiers for each atom in a compound facilitating construction of an atom-resolved metabolic network. What is more, this method is guaranteed to generate the same identifier for symmetric atoms, enabling automatic identification of …

Rethinking Fda Regulation Of Complex Products, Philip E. Alford

Minnesota Journal of Law, Science & Technology

No abstract provided.

Homicide And Drug Trafficking In Impoverished Communities In Brazil, Elenice De Souza Oliveira, Braulio Figueiredo Alves Da Silva, Flavio Luiz Sapori, Gabriela Gomes Cardoso

Department of Justice Studies Faculty Scholarship and Creative Works

Many studies demonstrate that homicides are heavily concentrated in impoverished neighborhoods, but not all socially disadvantaged neighborhoods are hotbeds of violence. Conducted in Belo Horizonte, Brazil, this study hypothesizes that the association between high rates of homicide and impoverished areas is influenced by the emergence of a specific type of street drug-dealing common to favelas (slums). The study applies econometric techniques to police data on homicides and drug arrests from 2008 to 2011, as well as 2010 Census data, to test its hypothesis. The findings provide insight into the development of crime prevention policies in areas of high social vulnerability.

Current Scenario Of Covid-19 With Epidemiological And Phylogenetic Analysis Of Pakistani Coronavirus: A Review, Asma Altaf, Wafa Iqbal, Sidra Younis, Farah Deeba

Journal of Bioresource Management

A novel corona virus named as 2019 n-CoV was identified to be the actual cause of an outbreak of respiratory illness in Wuhan, China beginning in late December 2019. This respiratory disease was named as COVID-19 by WHO. There are many countries affected by COVID-19 including Pakistan. In this review we have provided a brief introduction of COVID-19 and discussed epidemiological and phylogenetic analysis of Pakistani novel corona virus strain. Our epidemiological analysis of data till 16^th May 2020 showed rapidly increasing number of new cases, while at the same time a higher recovery rate than number of deaths …

Estimating Partial Body Ionizing Radiation Exposure By Automated Cytogenetic Biodosimetry, Peter Rogan

Biochemistry Publications

Purpose: Inhomogeneous exposures to ionizing radiation can be detected and quantified with the Dicentric Chromosome Assay (DCA) of metaphase cells. Complete automation of interpretation of the DCA for whole body irradiation has significantly improved throughput without compromising accuracy, however low levels of residual false positive dicentric chromosomes (DCs) have confounded its application for partial body exposure determination.

Materials and Methods: We describe a method of estimating and correcting for false positive DCs in digitally processed images of metaphase cells. Nearly all DCs detected in unirradiated calibration samples are introduced by digital image processing. DC frequencies of irradiated calibration …

Structural Insights Of Transcriptionally Active, Full-Length Androgen Receptor Coactivator Complexes, Xinzhe Yu, Ping Yi, Ross A Hamilton, Hong Shen, Muyuan Chen, Charles E Foulds, Michael A Mancini, Steven J Ludtke, Zhao Wang, Bert W O'Malley

Faculty, Staff and Students Publications

Steroid receptors activate gene transcription by recruiting coactivators to initiate transcription of their target genes. For most nuclear receptors, the ligand-dependent activation function domain-2 (AF-2) is a primary contributor to the nuclear receptor (NR) transcriptional activity. In contrast to other steroid receptors, such as ERα, the activation function of androgen receptor (AR) is largely dependent on its ligand-independent AF-1 located in its N-terminal domain (NTD). It remains unclear why AR utilizes a different AF domain from other receptors despite that NRs share similar domain organizations. Here, we present cryoelectron microscopy (cryo-EM) structures of DNA-bound full-length AR and its complex structure …

Berry Phenolic And Volatile Extracts Inhibit Pro-Inflammatory Cytokine Secretion In Lps-Stimulated Raw264.7 Cells Through Suppression Of Nf-Κb Signaling Pathway, Inah Gu, Cindi Brownmiller, Nathan Blaine Stebbins, Andy Mauromostakos, Luke Howard, Sun-Ok Lee

Food Science Faculty Publications and Presentations

Berries are a rich source of phytochemicals, especially phenolics well known for protective activity against many chronic diseases. Berries also contain a complex mixture of volatile compounds that are responsible for the unique aromas of berries. However, there is very limited information on the composition and potential health benefits of berry volatiles. In this study, we isolated phenolic and volatile fractions from six common berries and characterized them by HPLC/HPLC-MS and GC/GC-MS, respectively. Berry phenolic and volatile fractions were evaluated for an anti-inflammatory effect using lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells by measuring levels of pro-inflammatory cytokines and the nuclear factor-kappa …

Synthesis, Structure Elucidation And Selected Biological Activities Of Ag(I) And Au(I) Complexes Constructed From Thiosemicarbazone And Phosphine Ligands, Syahrina Nur ‘Ain Abdul Halim

Student Works (2020-2029)

New Ag(I) and Au(I) mixed ligand complexes were synthesised using thiosemicarbazone and phosphine in search of a new biologically active compounds. CHN elemental analysis, powder X-ray diffraction (PXRD), single crystal X-ray diffraction as well as several spectroscopic techniques such as FT-IR, Energy-dispersive X-ray (EDX), 1H, 13C, and 31P{1H} NMR were performed to elucidate the structure of these complexes. Elemental analysis suggested that the stoichiometry of the complexes formed by the reaction of Ag nitrate with thiosemicarbazone in the presence of phosphine was indeed 1:2:1 molar ratio, while for the Au to be in 1:1:1 molar ratio. The Ag and Au …

Mtor-Initiated Metabolic Switch And Degeneration In The Retinal Pigment Epithelium, Young-Mi Go, Jing Zhang, Jolyn Fernandes, Christopher Litwin, Rui Chen, Theodore G Wensel, Dean P Jones, Jiyang Cai, Yan Chen

Faculty, Staff and Students Publications

The retinal pigment epithelium (RPE) is a particularly vulnerable tissue to age-dependent degeneration. Over the life span, the RPE develops an expanded endo-lysosomal compartment to maintain the high efficiency of phagocytosis and degradation of photoreceptor outer segments (POS) necessary for photoreceptor survival. As the assembly and activation of the mechanistic target of rapamycin complex 1 (mTORC1) occur on the lysosome surface, increased lysosome mass with aging leads to higher mTORC1 activity. The functional consequences of hyperactive mTORC1 in the RPE are unclear. In the current study, we used integrated high-resolution metabolomic and genomic approaches to examine mice with RPE-specific deletion …

Characterization Of Retinal Biomechanical Properties Using Brillouin Microscopy, Yogeshwari S Ambekar, Manmohan Singh, Giuliano Scarcelli, Elda M Rueda, Benjamin M Hall, Ross A Poché, Kirill V Larin

Faculty, Staff and Students Publications

SIGNIFICANCE: The retina is critical for vision, and several diseases may alter its biomechanical properties. However, assessing the biomechanical properties of the retina nondestructively is a challenge due to its fragile nature and location within the eye globe. Advancements in Brillouin spectroscopy have provided the means for nondestructive investigations of retina biomechanical properties.

AIM: We assessed the biomechanical properties of mouse retinas using Brillouin microscopy noninvasively and showed the potential of Brillouin microscopy to differentiate the type and layers of retinas based on stiffness.

APPROACH: We used Brillouin microscopy to quantify stiffness of fresh and paraformaldehyde (PFA)-fixed retinas. As further …

Capsaicin Is A Negative Allosteric Modulator Of The 5-Ht3 Receptor, Eslam El Nebrisi, Tatiana Prytkova, Dietrich Ernst Lorke, Luke Howarth, Asma Hassan Alzaabi, Keun-Hang Susan Yang, Frank Christopher Howarth, Murat Oz

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this study, effects of capsaicin, an active ingredient of the capsicum plant, were investigated on human 5-hydroxytryptamine type 3 (5-HT₃) receptors. Capsaicin reversibly inhibited serotonin (5-HT)-induced currents recorded by two-electrode voltage clamp method in Xenopus oocytes. The inhibition was time- and concentration-dependent with an IC₅₀ = 62 μM. The effect of capsaicin was not altered in the presence of capsazepine, and by intracellular BAPTA injections or trans-membrane potential changes. In radio-ligand binding studies, capsaicin did not change the specific binding of the 5-HT₃ antagonist [³H]GR65630, indicating that it is a noncompetitive inhibitor of …

Ionophoric Polyphenols Are Permeable To The Blood Brain Barrier, Interact With Human Serum Albumin And Calf Thymus Dna, And Inhibit Ache Enzymatic Activity, Alberto Martinez, Mai Zahran, Miguel Gomez, Johnny Guevara, Rosemary Pichardo-Bueno, Junaid Asim, Gabriel Ortiz, Yaa Andoh, Sinji Shibutani, Baljit Kaur

Publications and Research

Alzheimer’s disease (AD) is the most common form of dementia that affects more than 40 million people around the world. The incidence is expected to rapidly increase due to the lack of any effective treatment. In previous work we synthesized a family of five ionophoric polyphenols (compounds 1–5) that targeted important aspects related to AD, such as the toxic aggregation of amyloid-β peptides, the production of reactive oxygen species, or the excessive presence of Cu²⁺ ions. Here, in order to gain insights into their potential therapeutic value, we have tested the ability of compounds 1– …

Structure And Mechanism Of A Unique Diiron Center In Mammalian Stearoyl-Coa Desaturase, Jiemin Shen, Gang Wu, Ah-Lim Tsai, Ming Zhou

Faculty, Staff and Students Publications

Stearoyl-CoA desaturase 1 (SCD1) is a membrane-embedded metalloenzyme that catalyzes formation of a double-bond on a saturated acyl-CoA. SCD1 has a diiron center and its proper function requires an electron transport chain composed of NADH (or NADPH), cytochrome b5 reductase (b5R), and cytochrome b5 (cyt b5). Since SCD1 is a key regulator in fat metabolism and is required for survival of cancer cells, there is intense interest in targeting SCD1 for various metabolic diseases and cancers. Crystal structures of human and mouse SCD1 were reported recently, however, both proteins have two zinc ions instead of two iron ions in the …

Modulation Of Escherichia Coli Translation By The Specific Inactivation Of TrnaGly Under Oxidative Stress, Lorenzo Eugenio Leiva, Andrea Pincheira, Sara Elgamal, Sandra D. Kienast, Verónica Bravo, Johannes Leufken, Daniela Gutiérrez, Sebastian A. Leidel, Michael Ibba, Assaf Katz

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bacterial oxidative stress responses are generally controlled by transcription factors that modulate the synthesis of RNAs with the aid of some sRNAs that control the stability, and in some cases the translation, of specific mRNAs. Here, we report that oxidative stress additionally leads to inactivation of tRNA^Gly in Escherichia coli, inducing a series of physiological changes. The observed inactivation of tRNA^Gly correlated with altered efficiency of translation of Gly codons, suggesting a possible mechanism of translational control of gene expression under oxidative stress. Changes in translation also depended on the availability of glycine, revealing a mechanism whereby bacteria …

The Ubiquitin Ligase Cullin-1 Associates With Chromatin And Regulates Transcription Of Specific C-Myc Target Genes, Melanie A Sweeney, Polina Iakova, Laure Maneix, Fu-Yuan Shih, Hannah E Cho, Ergun Sahin, Andre Catic

Faculty, Staff and Students Publications

Transcription is regulated through a dynamic interplay of DNA-associated proteins, and the composition of gene-regulatory complexes is subject to continuous adjustments. Protein alterations include post-translational modifications and elimination of individual polypeptides. Spatially and temporally controlled protein removal is, therefore, essential for gene regulation and accounts for the short half-life of many transcription factors. The ubiquitin-proteasome system is responsible for site- and target-specific ubiquitination and protein degradation. Specificity of ubiquitination is conferred by ubiquitin ligases. Cullin-RING complexes, the largest family of ligases, require multi-unit assembly around one of seven cullin proteins. To investigate the direct role of cullins in ubiquitination of …