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

Selective Inhibition Of N-Linked Glycosylation Impairs Receptor Tyrosine Kinase Processing, Elsenoor Klaver, Peng Zhao, Melanie May, Heather Flanagan-Steet, Hudson H. Freeze, Reid Gilmore, Lance Wells, Joseph Contessa, Richard Steet Jun 2019

Selective Inhibition Of N-Linked Glycosylation Impairs Receptor Tyrosine Kinase Processing, Elsenoor Klaver, Peng Zhao, Melanie May, Heather Flanagan-Steet, Hudson H. Freeze, Reid Gilmore, Lance Wells, Joseph Contessa, Richard Steet

Open Access Articles

Global inhibition of N-linked glycosylation broadly reduces glycan occupancy on glycoproteins, but identifying how this inhibition functionally impacts specific glycoproteins is challenging. This limits our understanding of pathogenesis in the congenital disorders of glycosylation (CDG). We used selective exo-enzymatic labeling of cells deficient in the two catalytic subunits of oligosaccharyltransferase - STT3A and STT3B - to monitor the presence and glycosylation status of cell surface glycoproteins. We show reduced abundance of two canonical tyrosine receptor kinases - the insulin receptor and insulin-like growth factor 1 receptor (IGF-1R) - at the cell surface in STT3A-null cells, due to decreased N-linked glycan site occupancy and proteolytic ...


Adipocyte Acly Facilitates Dietary Carbohydrate Handling To Maintain Metabolic Homeostasis In Females, Sully Fernandez, John M. Viola, Annmarie Torres, Martina Wallace, Sophie Trefely, Steven Zhao, Hayley C. Affronti, Jivani M. Gengatharan, David A. Guertin, Nathaniel W. Snyder, Christian M. Metallo, Kathryn E. Wellen May 2019

Adipocyte Acly Facilitates Dietary Carbohydrate Handling To Maintain Metabolic Homeostasis In Females, Sully Fernandez, John M. Viola, Annmarie Torres, Martina Wallace, Sophie Trefely, Steven Zhao, Hayley C. Affronti, Jivani M. Gengatharan, David A. Guertin, Nathaniel W. Snyder, Christian M. Metallo, Kathryn E. Wellen

Open Access Articles

Sugars and refined carbohydrates are major components of the modern diet. ATP-citrate lyase (ACLY) is upregulated in adipocytes in response to carbohydrate consumption and generates acetyl-coenzyme A (CoA) for both lipid synthesis and acetylation reactions. Here, we investigate the role of ACLY in the metabolic and transcriptional responses to carbohydrates in adipocytes and unexpectedly uncover a sexually dimorphic function in maintaining systemic metabolic homeostasis. When fed a high-sucrose diet, Acly(FAT-/-) females exhibit a lipodystrophy-like phenotype, with minimal fat accumulation, insulin resistance, and hepatic lipid accumulation, whereas Acly(FAT-/-) males have only mild metabolic phenotypes. We find that ACLY is ...


Ouabain Enhances Cell-Cell Adhesion Mediated By Beta1 Subunits Of The Na(+),K(+)-Atpase In Cho Fibroblasts, Claudia Andrea Vilchis-Nestor, Maria Luisa Roldan, Angelina Leonardi, Juan G. Navea, Teresita Padilla-Benavides, Liora Shoshani Apr 2019

Ouabain Enhances Cell-Cell Adhesion Mediated By Beta1 Subunits Of The Na(+),K(+)-Atpase In Cho Fibroblasts, Claudia Andrea Vilchis-Nestor, Maria Luisa Roldan, Angelina Leonardi, Juan G. Navea, Teresita Padilla-Benavides, Liora Shoshani

Open Access Articles

Adhesion is a crucial characteristic of epithelial cells to form barriers to pathogens and toxic substances from the environment. Epithelial cells attach to each other using intercellular junctions on the lateral membrane, including tight and adherent junctions, as well as the Na(+),K(+)-ATPase. Our group has shown that non-adherent chinese hamster ovary (CHO) cells transfected with the canine beta1 subunit become adhesive, and those homotypic interactions amongst beta1 subunits of the Na(+),K(+)-ATPase occur between neighboring epithelial cells. Ouabain, a cardiotonic steroid, binds to the alpha subunit of the Na(+),K(+)-ATPase, inhibits the pump activity and induces ...


Exercise Rescues Gene Pathways Involved In Vascular Expansion And Promotes Functional Angiogenesis In Subcutaneous White Adipose Tissue, So Yun Min, Heather Learnard, Shashi Kant, Olga Gaelikman, Raziel Rojas-Rodriguez, Tiffany Desouza, Anand Desai, John F. Keaney Jr., Silvia Corvera, Siobhan M. Craige Apr 2019

Exercise Rescues Gene Pathways Involved In Vascular Expansion And Promotes Functional Angiogenesis In Subcutaneous White Adipose Tissue, So Yun Min, Heather Learnard, Shashi Kant, Olga Gaelikman, Raziel Rojas-Rodriguez, Tiffany Desouza, Anand Desai, John F. Keaney Jr., Silvia Corvera, Siobhan M. Craige

Open Access Articles

Exercise mitigates chronic diseases such as diabetes, cardiovascular diseases, and obesity; however, the molecular mechanisms governing protection from these diseases are not completely understood. Here we demonstrate that exercise rescues metabolically compromised high fat diet (HFD) fed mice, and reprograms subcutaneous white adipose tissue (scWAT). Using transcriptomic profiling, scWAT was analyzed for HFD gene expression changes that were rescued by exercise. Gene networks involved in vascularization were identified as prominent targets of exercise, which led us to investigate the vasculature architecture and endothelial phenotype. Vascular density in scWAT was found to be compromised in HFD, and exercise rescued this defect ...


A Persistence Detector For Metabolic Network Rewiring In An Animal, Jote T. Bulcha, Gabrielle E. Giese, Zulfikar Ali, Yong-Uk Lee, Melissa D. Walker, Amy D. Holdorf, L. Safak Yilmaz, Robert C. Brewster, Albertha J. M. Walhout Jan 2019

A Persistence Detector For Metabolic Network Rewiring In An Animal, Jote T. Bulcha, Gabrielle E. Giese, Zulfikar Ali, Yong-Uk Lee, Melissa D. Walker, Amy D. Holdorf, L. Safak Yilmaz, Robert C. Brewster, Albertha J. M. Walhout

Open Access Articles

Biological systems must possess mechanisms that prevent inappropriate responses to spurious environmental inputs. Caenorhabditis elegans has two breakdown pathways for the short-chain fatty acid propionate: a canonical, vitamin B12-dependent pathway and a propionate shunt that is used when vitamin B12 levels are low. The shunt pathway is kept off when there is sufficient flux through the canonical pathway, likely to avoid generating shunt-specific toxic intermediates. Here, we discovered a transcriptional regulatory circuit that activates shunt gene expression upon propionate buildup. Nuclear hormone receptor 10 (NHR-10) and NHR-68 function together as a "persistence detector" in a type 1, coherent feed-forward loop ...


Orbit: A New Paradigm For Genetic Engineering Of Mycobacterial Chromosomes, Kenan C. Murphy, Samantha J. Nelson, Subhalaxmi Nambi, Kadamba Papavinasasundaram, Christina E. Baer, Christopher M. Sassetti Dec 2018

Orbit: A New Paradigm For Genetic Engineering Of Mycobacterial Chromosomes, Kenan C. Murphy, Samantha J. Nelson, Subhalaxmi Nambi, Kadamba Papavinasasundaram, Christina E. Baer, Christopher M. Sassetti

Open Access Articles

Two efficient recombination systems were combined to produce a versatile method for chromosomal engineering that obviates the need to prepare double-stranded DNA (dsDNA) recombination substrates. A synthetic "targeting oligonucleotide" is incorporated into the chromosome via homologous recombination mediated by the phage Che9c RecT annealase. This oligonucleotide contains a site-specific recombination site for the directional Bxb1 integrase (Int), which allows the simultaneous integration of a "payload plasmid" that contains a cognate recombination site and a selectable marker. The targeting oligonucleotide and payload plasmid are cotransformed into a RecT- and Int-expressing strain, and drug-resistant homologous recombinants are selected in a single step ...


The Caenorhabditis Elegans Oxidative Stress Response Requires The Nhr-49 Transcription Factor, Queenie Hu, Dayana R. D'Amora, Lesley T. Macneil, Albertha J. M. Walhout, Terrance J. Kubiseski Dec 2018

The Caenorhabditis Elegans Oxidative Stress Response Requires The Nhr-49 Transcription Factor, Queenie Hu, Dayana R. D'Amora, Lesley T. Macneil, Albertha J. M. Walhout, Terrance J. Kubiseski

Open Access Articles

The overproduction of reactive oxygen species (ROS) in cells can lead to the development of diseases associated with aging. We have previously shown that C. elegans BRAP-2 (Brca1 associated binding protein 2) regulates phase II detoxification genes such as gst-4, by increasing SKN-1 activity. Previously, a transcription factor (TF) RNAi screen was conducted to identify potential activators that are required to induce gst-4 expression in brap-2(ok1492) mutants. The lipid metabolism regulator NHR-49/HNF4 was among 18 TFs identified. Here, we show that knockdown of nhr-49 suppresses the activation of gst-4 caused by brap-2 inactivation and that gain-of-function alleles of ...


Potent Cas9 Inhibition In Bacterial And Human Cells By Acriic4 And Acriic5 Anti-Crispr Proteins, Jooyoung Lee, Aamir Mir, Alireza Edraki, Bianca Garcia, Nadia Amrani, Hannah E. Lou, Ildar Gainetdinov, April Pawluk, Raed Ibraheim, Xin D. Gao, Pengpeng Liu, Alan R. Davidson, Karen L. Maxwell, Erik J. Sontheimer Dec 2018

Potent Cas9 Inhibition In Bacterial And Human Cells By Acriic4 And Acriic5 Anti-Crispr Proteins, Jooyoung Lee, Aamir Mir, Alireza Edraki, Bianca Garcia, Nadia Amrani, Hannah E. Lou, Ildar Gainetdinov, April Pawluk, Raed Ibraheim, Xin D. Gao, Pengpeng Liu, Alan R. Davidson, Karen L. Maxwell, Erik J. Sontheimer

Open Access Articles

In their natural settings, CRISPR-Cas systems play crucial roles in bacterial and archaeal adaptive immunity to protect against phages and other mobile genetic elements, and they are also widely used as genome engineering technologies. Previously we discovered bacteriophage-encoded Cas9-specific anti-CRISPR (Acr) proteins that serve as countermeasures against host bacterial immunity by inactivating their CRISPR-Cas systems (A. Pawluk, N. Amrani, Y. Zhang, B. Garcia, et al., Cell 167:1829-1838.e9, 2016, https://doi.org/10.1016/j.cell.2016.11.017). We hypothesized that the evolutionary advantages conferred by anti-CRISPRs would drive the widespread occurrence of these proteins in nature (K ...


Stress-Responsive And Metabolic Gene Regulation Are Altered In Low S-Adenosylmethionine, Wei Ding, Daniel P. Higgins, Dilip K. Yadav, Adwait A. Godbole, Read Pukkila-Worley, Amy K. Walker Nov 2018

Stress-Responsive And Metabolic Gene Regulation Are Altered In Low S-Adenosylmethionine, Wei Ding, Daniel P. Higgins, Dilip K. Yadav, Adwait A. Godbole, Read Pukkila-Worley, Amy K. Walker

Open Access Articles

S-adenosylmethionine (SAM) is a donor which provides the methyl groups for histone or nucleic acid modification and phosphatidylcholine production. SAM is hypothesized to link metabolism and chromatin modification, however, its role in acute gene regulation is poorly understood. We recently found that Caenorhabditis elegans with reduced SAM had deficiencies in H3K4 trimethylation (H3K4me3) at pathogen-response genes, decreasing their expression and limiting pathogen resistance. We hypothesized that SAM may be generally required for stress-responsive transcription. Here, using genetic assays, we show that transcriptional responses to bacterial or xenotoxic stress fail in C. elegans with low SAM, but that expression of heat ...


Genome-Wide Crispr Screens For Shiga Toxins And Ricin Reveal Golgi Proteins Critical For Glycosylation, Songhai Tian, Khaja Muneeruddin, Mei Yuk Choi, Liang Tao, Robiul H. Bhuiyan, Yuhsuke Ohmi, Keiko Furukawa, Koichi Furukawa, Sebastian Boland, Scott A. Shaffer, Rosalyn M. Adam, Min Dong Nov 2018

Genome-Wide Crispr Screens For Shiga Toxins And Ricin Reveal Golgi Proteins Critical For Glycosylation, Songhai Tian, Khaja Muneeruddin, Mei Yuk Choi, Liang Tao, Robiul H. Bhuiyan, Yuhsuke Ohmi, Keiko Furukawa, Koichi Furukawa, Sebastian Boland, Scott A. Shaffer, Rosalyn M. Adam, Min Dong

Open Access Articles

Glycosylation is a fundamental modification of proteins and membrane lipids. Toxins that utilize glycans as their receptors have served as powerful tools to identify key players in glycosylation processes. Here, we carried out Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9-mediated genome-wide loss-of-function screens using two related bacterial toxins, Shiga-like toxins (Stxs) 1 and 2, which use a specific glycolipid, globotriaosylceramide (Gb3), as receptors, and the plant toxin ricin, which recognizes a broad range of glycans. The Stxs screens identified major glycosyltransferases (GTs) and transporters involved in Gb3 biosynthesis, while the ricin screen identified GTs and transporters involved in N-linked ...


A Population Of Gut Epithelial Enterochromaffin Cells Is Mechanosensitive And Requires Piezo2 To Convert Force Into Serotonin Release, Constanza Alcaino, Kaitlyn R. Knutson, Anthony J. Treichel, Gulcan Yildiz, Peter R. Strege, David R. Linden, Joyce H. Li, Andrew B. Leiter, Joseph H. Szurszewski, Gianrico Farrugia, Arthur Beyder Aug 2018

A Population Of Gut Epithelial Enterochromaffin Cells Is Mechanosensitive And Requires Piezo2 To Convert Force Into Serotonin Release, Constanza Alcaino, Kaitlyn R. Knutson, Anthony J. Treichel, Gulcan Yildiz, Peter R. Strege, David R. Linden, Joyce H. Li, Andrew B. Leiter, Joseph H. Szurszewski, Gianrico Farrugia, Arthur Beyder

Open Access Articles

Enterochromaffin (EC) cells constitute the largest population of intestinal epithelial enteroendocrine (EE) cells. EC cells are proposed to be specialized mechanosensory cells that release serotonin in response to epithelial forces, and thereby regulate intestinal fluid secretion. However, it is unknown whether EE and EC cells are directly mechanosensitive, and if so, what the molecular mechanism of their mechanosensitivity is. Consequently, the role of EE and EC cells in gastrointestinal mechanobiology is unclear. Piezo2 mechanosensitive ion channels are important for some specialized epithelial mechanosensors, and they are expressed in mouse and human EC cells. Here, we use EC and EE cell ...


Llc Tumor Cells-Derivated Factors Reduces Adipogenesis In Co-Culture System, Magno Alves Lopes, Felipe Oliveira Franco, Felipe Henriques, Sidney Barnabe Peres, Miguel Luiz Batista Jr. Jul 2018

Llc Tumor Cells-Derivated Factors Reduces Adipogenesis In Co-Culture System, Magno Alves Lopes, Felipe Oliveira Franco, Felipe Henriques, Sidney Barnabe Peres, Miguel Luiz Batista Jr.

Open Access Articles

Cancer cachexia (CC) is a multifactorial syndrome with an unknown etiology. The primary symptom is the progressive reduction of the body weight. Recently, down-regulation of adipogenic and lipogenic genes were demonstrated to be early affected during cachexia progression in adipose tissue (AT), resulting in AT remodeling. Thus, this study aimed to evaluate in a co-culture system the influence of the Lewis Lung Carcinoma (LLC) tumor cells (c/c-LLC) in an established pre-adipocyte cell line 3T3-L1 adipogenic capacity. c/c-LLC in the presence of 3T3-L1 caused a reduction in lipids accumulation, suggesting that secretory tumor cells products may affect adipogenesis. Interestingly ...


Inhibition Of Protein Arginine Methyltransferase 5 Enhances Hepatic Mitochondrial Biogenesis, Lei Huang, Jehnan Liu, Xiao-Ou Zhang, Katelyn Sibley, Sonia M. Najjar, Mary M. Lee, Joae Qiong Wu Jul 2018

Inhibition Of Protein Arginine Methyltransferase 5 Enhances Hepatic Mitochondrial Biogenesis, Lei Huang, Jehnan Liu, Xiao-Ou Zhang, Katelyn Sibley, Sonia M. Najjar, Mary M. Lee, Joae Qiong Wu

Open Access Articles

Protein arginine methyltransferase 5 (PRMT5) regulates gene expression either transcriptionallyly by symmetric dimethylation of arginine residues on histones H4R3, H3R8 and H2AR3, or at the post-translational level by methylation of non-histone target proteins. While emerging evidence suggests that PRMT5 functions as an oncogene, its role in metabolic diseases is not well defined. We investigated the role of PRMT5 in promoting high fat-induced hepatic steatosis. High fat diet up-regulated PRMT5 levels in the liver, but not in other metabolically relevant tissues such as skeletal muscle or white and brown adipose tissue. This was associated with repression of master transcription regulators involved ...


Neuronal Modulation Of Brown Adipose Activity Through Perturbation Of White Adipocyte Lipogenesis, Adilson L. Guilherme, David J. Pedersen, Felipe Henriques, Alexander H. Bedard, Elizabeth Henchey, Mark Kelly, Donald A. Morgan, Kamal Rahmouni, Michael P. Czech Jun 2018

Neuronal Modulation Of Brown Adipose Activity Through Perturbation Of White Adipocyte Lipogenesis, Adilson L. Guilherme, David J. Pedersen, Felipe Henriques, Alexander H. Bedard, Elizabeth Henchey, Mark Kelly, Donald A. Morgan, Kamal Rahmouni, Michael P. Czech

Open Access Articles

OBJECTIVE: Crosstalk between adipocytes and local neurons may be an important regulatory mechanism to control energy homeostasis. We previously reported that perturbation of adipocyte de novo lipogenesis (DNL) by deletion of fatty acid synthase (FASN) expands sympathetic neurons within white adipose tissue (WAT) and stimulates the appearance of "beige" adipocytes. Here we tested whether WAT DNL activity can also influence neuronal regulation and thermogenesis in brown adipose tissue (BAT).

METHODS AND RESULTS: Induced deletion of FASN in all adipocytes in mature mice (iAdFASNKO) enhanced sympathetic innervation and neuronal activity as well as UCP1 expression in both WAT and BAT. This ...


Rna Polymerase Ii Transcription Attenuation At The Yeast Dna Repair Gene, Def1, Involves Sen1-Dependent And Polyadenylation Site-Dependent Termination, Courtney Whalen, Christine Tuohy, Thomas Tallo, James W. Kaufman, Claire Moore, Jason N. Kuehner May 2018

Rna Polymerase Ii Transcription Attenuation At The Yeast Dna Repair Gene, Def1, Involves Sen1-Dependent And Polyadenylation Site-Dependent Termination, Courtney Whalen, Christine Tuohy, Thomas Tallo, James W. Kaufman, Claire Moore, Jason N. Kuehner

Open Access Articles

Termination of RNA Polymerase II (Pol II) activity serves a vital cellular role by separating ubiquitous transcription units and influencing RNA fate and function. In the yeast Saccharomyces cerevisiae, Pol II termination is carried out by cleavage and polyadenylation factor (CPF-CF) and Nrd1-Nab3-Sen1 (NNS) complexes, which operate primarily at mRNA and non-coding RNA genes, respectively. Premature Pol II termination (attenuation) contributes to gene regulation, but there is limited knowledge of its prevalence and biological significance. In particular, it is unclear how much crosstalk occurs between CPF-CF and NNS complexes and how Pol II attenuation is modulated during stress adaptation. In ...


N-Terminal Sumoylation Of Centromeric Histone H3 Variant Cse4 Regulates Its Proteolysis To Prevent Mislocalization To Non-Centromeric Chromatin, Kentaro Ohkuni, Reuben Levy-Myers, Jack Warren, Wei-Chun Au, Yoshimitsu Takahashi, Richard E. Baker, Munira A. Basrai Mar 2018

N-Terminal Sumoylation Of Centromeric Histone H3 Variant Cse4 Regulates Its Proteolysis To Prevent Mislocalization To Non-Centromeric Chromatin, Kentaro Ohkuni, Reuben Levy-Myers, Jack Warren, Wei-Chun Au, Yoshimitsu Takahashi, Richard E. Baker, Munira A. Basrai

Open Access Articles

Stringent regulation of cellular levels of evolutionarily conserved centromeric histone H3 variant (CENP-A in humans, CID in flies, Cse4 in yeast) prevents its mislocalization to non-centromeric chromatin. Overexpression and mislocalization of CENP-A has been observed in cancers and leads to aneuploidy in yeast, flies, and human cells. Ubiquitin-mediated proteolysis of Cse4 by E3 ligases such as Psh1 and Sumo-Targeted Ubiquitin Ligase (STUbL) Slx5 prevent mislocalization of Cse4. Previously, we identified Siz1 and Siz2 as the major E3 ligases for sumoylation of Cse4. In this study, we have identified lysine 65 (K65) in Cse4 as a site that regulates sumoylation and ...


Cbx4 Sumoylates Prdm16 To Regulate Adipose Tissue Thermogenesis, Qingbo Chen, Lei Huang, Dongning Pan, Lihua (Julie) Zhu, Yong-Xu Wang Mar 2018

Cbx4 Sumoylates Prdm16 To Regulate Adipose Tissue Thermogenesis, Qingbo Chen, Lei Huang, Dongning Pan, Lihua (Julie) Zhu, Yong-Xu Wang

Open Access Articles

Transcriptional co-activator Prdm16 controls brown fat development and white fat browning, but how this thermogenic function is modulated post-translationally is poorly understood. Here, we report that Cbx4, a Polycomb group protein, is a SUMO E3 ligase for Prdm16 and that Cbx4-mediated sumoylation of Prdm16 is required for thermogenic gene expression. Cbx4 expression is enriched in brown fat and is induced in adipose tissue by acute cold exposure. Sumoylation of Prdm16 at lysine 917 by Cbx4 blocks its ubiquitination-mediated degradation, thereby augmenting its stability and thermogenic function. Moreover, this sumoylation event primes Prdm16 to be further stabilized by methyltransferase Ehmt1. Heterozygous ...


Molecular Mechanisms Of Cell Death: Recommendations Of The Nomenclature Committee On Cell Death 2018, Lorenzo Galluzzi, Eric H. Baehrecke, Francis Ka-Ming Chan, Guido Kroemer Mar 2018

Molecular Mechanisms Of Cell Death: Recommendations Of The Nomenclature Committee On Cell Death 2018, Lorenzo Galluzzi, Eric H. Baehrecke, Francis Ka-Ming Chan, Guido Kroemer

Open Access Articles

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell ...


Dznep Inhibits H3k27me3 Deposition And Delays Retinal Degeneration In The Rd1 Mice, Shijie Zheng, Lirong Xiao, Yu Liu, Yujiao Wang, Lin Cheng, Junjun Zhang, Naihong Yan, Danian Chen Feb 2018

Dznep Inhibits H3k27me3 Deposition And Delays Retinal Degeneration In The Rd1 Mice, Shijie Zheng, Lirong Xiao, Yu Liu, Yujiao Wang, Lin Cheng, Junjun Zhang, Naihong Yan, Danian Chen

Open Access Articles

Retinitis pigmentosa (RP) is a group of inherited retinal degenerative diseases causing progressive loss of photoreceptors. Numerous gene mutations are identified to be related with RP, but epigenetic modifications may also be involved in the pathogenesis. Previous studies suggested that both DNA methylation and histone acetylation regulate photoreceptor cell death in RP mouse models. However, the role of histone methylation in RP has never been investigated. In this study, we found that trimethylation of several lysine sites of histone H3, including lysine 27 (H3K27me3), increased in the retinas of rd1 mice. Histone methylation inhibitor DZNep significantly reduced the calpain activity ...


Thermophilic Adaptation In Prokaryotes Is Constrained By Metabolic Costs Of Proteostasis, Sergey V. Venev, Konstantin B. Zeldovich Jan 2018

Thermophilic Adaptation In Prokaryotes Is Constrained By Metabolic Costs Of Proteostasis, Sergey V. Venev, Konstantin B. Zeldovich

Open Access Articles

Prokaryotes evolved to thrive in an extremely diverse set of habitats, and their proteomes bear signatures of environmental conditions. Although correlations between amino acid usage and environmental temperature are well-documented, understanding of the mechanisms of thermal adaptation remains incomplete. Here, we couple the energetic costs of protein folding and protein homeostasis to build a microscopic model explaining both the overall amino acid composition and its temperature trends. Low biosynthesis costs lead to low diversity of physical interactions between amino acid residues, which in turn makes proteins less stable and drives up chaperone activity to maintain appropriate levels of folded, functional ...


Attaching-And-Effacing Pathogens Exploit Junction Regulatory Activities Of N-Wasp And Snx9 To Disrupt The Intestinal Barrier, John J. Garber, Emily M. Mallick, Karen M. Scanlon, Jerrold R. Turner, Michael S. Donnenberg, John M. Leong, Scott B. Snapper Dec 2017

Attaching-And-Effacing Pathogens Exploit Junction Regulatory Activities Of N-Wasp And Snx9 To Disrupt The Intestinal Barrier, John J. Garber, Emily M. Mallick, Karen M. Scanlon, Jerrold R. Turner, Michael S. Donnenberg, John M. Leong, Scott B. Snapper

Open Access Articles

Background and Aims: Neural Wiskott-Aldrich Syndrome protein (N-WASP) is a key regulator of the actin cytoskeleton in epithelial tissues and is poised to mediate cytoskeletal-dependent aspects of apical junction complex (AJC) homeostasis. Attaching-and-effacing (AE) pathogens disrupt this homeostasis through translocation of the effector molecule early secreted antigenic target-6 (ESX)-1 secretion-associated protein F (EspF). Although the mechanisms underlying AJC disruption by EspF are unknown, EspF contains putative binding sites for N-WASP and the endocytic regulator sorting nexin 9 (SNX9). We hypothesized that N-WASP regulates AJC integrity and AE pathogens use EspF to induce junction disassembly through an N-WASP- and SNX9-dependent ...


Transcription Factor Hlx Controls A Systematic Switch From White To Brown Fat Through Prdm16-Mediated Co-Activation, Lei Huang, Dongning Pan, Qingbo Chen, Lihua (Julie) Zhu, Jianhong Ou, Martin Wabitsch, Yong-Xu Wang Jul 2017

Transcription Factor Hlx Controls A Systematic Switch From White To Brown Fat Through Prdm16-Mediated Co-Activation, Lei Huang, Dongning Pan, Qingbo Chen, Lihua (Julie) Zhu, Jianhong Ou, Martin Wabitsch, Yong-Xu Wang

Open Access Articles

Browning of subcutaneous white fat (iWAT) involves several reprograming events, but the underlying mechanisms are incompletely understood. Here we show that the transcription factor Hlx is selectively expressed in brown adipose tissue (BAT) and iWAT, and is translationally upregulated by beta3-adrenergic signaling-mediated suppression of the translational inhibitor 4E-BP1. Hlx interacts with and is co-activated by Prdm16 to control BAT-selective gene expression and mitochondrial biogenesis. Hlx heterozygous knockout mice have defects in brown-like adipocyte formation in iWAT, and develop glucose intolerance and high fat-induced hepatic steatosis. Conversely, transgenic expression of Hlx at a physiological level drives a full program of thermogenesis ...


Mutational Re-Modeling Of Di-Aspartyl Intramembrane Proteases: Uncoupling Physiologically-Relevant Activities From Those Associated With Alzheimer's Disease, Anastasia P. Grigorenko, Youri K. Moliaka, Olga V. Plotnikova, Alexander Smirnov, Vera A. Nikishina, Andrey Y. Goltsov, Fedor Gusev, Tatiana V. Andreeva, Omar Nelson, Ilya Bezprozvanny, Evgeny I. Rogaev May 2017

Mutational Re-Modeling Of Di-Aspartyl Intramembrane Proteases: Uncoupling Physiologically-Relevant Activities From Those Associated With Alzheimer's Disease, Anastasia P. Grigorenko, Youri K. Moliaka, Olga V. Plotnikova, Alexander Smirnov, Vera A. Nikishina, Andrey Y. Goltsov, Fedor Gusev, Tatiana V. Andreeva, Omar Nelson, Ilya Bezprozvanny, Evgeny I. Rogaev

Open Access Articles

The intramembrane proteolytic activities of presenilins (PSEN1/PS1 and PSEN2/PS2) underlie production of beta-amyloid, the key process in Alzheimer's disease (AD). Dysregulation of presenilin-mediated signaling is linked to cancers. Inhibition of the gamma-cleavage activities of PSENs that produce Abeta, but not the epsilon-like cleavage activity that release physiologically essential transcription activators, is a potential approach for the development of rational therapies for AD. In order to identify whether different activities of PSEN1 can be dissociated, we designed multiple mutations in the evolutionary conserved sites of PSEN1. We tested them in vitro and in vivo assays and compared their ...


Global Increase In Replication Fork Speed During A P57kip2-Regulated Erythroid Cell Fate Switch, Yung Hwang, Melinda Futran, Daniel Hidalgo, Ramona Pop, Divya Ramalingam Iyer, Ralph Scully, Nicholas R. Rhind, Merav Socolovsky May 2017

Global Increase In Replication Fork Speed During A P57kip2-Regulated Erythroid Cell Fate Switch, Yung Hwang, Melinda Futran, Daniel Hidalgo, Ramona Pop, Divya Ramalingam Iyer, Ralph Scully, Nicholas R. Rhind, Merav Socolovsky

Open Access Articles

Cell cycle regulators are increasingly implicated in cell fate decisions, such as the acquisition or loss of pluripotency and self-renewal potential. The cell cycle mechanisms that regulate these cell fate decisions are largely unknown. We studied an S phase-dependent cell fate switch, in which murine early erythroid progenitors transition in vivo from a self-renewal state into a phase of active erythroid gene transcription and concurrent maturational cell divisions. We found that progenitors are dependent on p57KIP2-mediated slowing of replication forks for self-renewal, a novel function for cyclin-dependent kinase inhibitors. The switch to differentiation entails rapid down-regulation of p57KIP2 with a ...


Inhibition Or Stimulation Of Autophagy Affects Early Formation Of Lipofuscin-Like Autofluorescence In The Retinal Pigment Epithelium Cell, Lei Lei, Radouil T. Tzekov, Huapeng Li, J. Hugh Mcdowell, Guangping Gao, W. Clay Smith, Shibo Tang, Shalesh Kaushal Mar 2017

Inhibition Or Stimulation Of Autophagy Affects Early Formation Of Lipofuscin-Like Autofluorescence In The Retinal Pigment Epithelium Cell, Lei Lei, Radouil T. Tzekov, Huapeng Li, J. Hugh Mcdowell, Guangping Gao, W. Clay Smith, Shibo Tang, Shalesh Kaushal

Open Access Articles

The accumulation of lipofuscin in the retinal pigment epithelium (RPE) is dependent on the effectiveness of photoreceptor outer segment material degradation. This study explored the role of autophagy in the fate of RPE lipofuscin degradation. After seven days of feeding with either native or modified rod outer segments, ARPE-19 cells were treated with enhancers or inhibitors of autophagy and the autofluorescence was detected by fluorescence-activated cell sorting. Supplementation with different types of rod outer segments increased lipofuscin-like autofluorescence (LLAF) after the inhibition of autophagy, while the induction of autophagy (e.g., application of rapamycin) decreased LLAF. The effects of autophagy ...


Phosphorylation Of Cardiac Myosin Binding Protein C Releases Myosin Heads From The Surface Of Cardiac Thick Filaments, Robert W. Kensler, Roger Craig, Richard L. Moss Feb 2017

Phosphorylation Of Cardiac Myosin Binding Protein C Releases Myosin Heads From The Surface Of Cardiac Thick Filaments, Robert W. Kensler, Roger Craig, Richard L. Moss

Open Access Articles

Cardiac myosin binding protein C (cMyBP-C) has a key regulatory role in cardiac contraction, but the mechanism by which changes in phosphorylation of cMyBP-C accelerate cross-bridge kinetics remains unknown. In this study, we isolated thick filaments from the hearts of mice in which the three serine residues (Ser273, Ser282, and Ser302) that are phosphorylated by protein kinase A in the m-domain of cMyBP-C were replaced by either alanine or aspartic acid, mimicking the fully nonphosphorylated and the fully phosphorylated state of cMyBP-C, respectively. We found that thick filaments from the cMyBP-C phospho-deficient hearts had highly ordered cross-bridge arrays, whereas the ...


Systemic Insulin Sensitivity Is Regulated By Gps2 Inhibition Of Akt Ubiquitination And Activation In Adipose Tissue, Carly T. Cederquist, Claudia Lentucci, Camila Martinez Calejman, Vanessa Hayashi, Joseph Orofino, David A. Guertin, Susan K. Fried, Mi-Jeong Lee, M. Dafne Cardamone, Valentina Perissi Jan 2017

Systemic Insulin Sensitivity Is Regulated By Gps2 Inhibition Of Akt Ubiquitination And Activation In Adipose Tissue, Carly T. Cederquist, Claudia Lentucci, Camila Martinez Calejman, Vanessa Hayashi, Joseph Orofino, David A. Guertin, Susan K. Fried, Mi-Jeong Lee, M. Dafne Cardamone, Valentina Perissi

Open Access Articles

OBJECTIVE: Insulin signaling plays a unique role in the regulation of energy homeostasis and the impairment of insulin action is associated with altered lipid metabolism, obesity, and Type 2 Diabetes. The main aim of this study was to provide further insight into the regulatory mechanisms governing the insulin signaling pathway by investigating the role of non-proteolytic ubiquitination in insulin-mediated activation of AKT.

METHODS: The molecular mechanism of AKT regulation through ubiquitination is first dissected in vitro in 3T3-L1 preadipocytes and then validated in vivo using mice with adipo-specific deletion of GPS2, an endogenous inhibitor of Ubc13 activity (GPS2-AKO mice).

RESULTS ...


A Gene-Centered C. Elegans Protein-Dna Interaction Network Provides A Framework For Functional Predictions, Juan Fuxman Bass, Carles Pons, Lucie Kozlowski, John S. Reece-Hoyes, Shaleen Shrestha, Amy D. Holdorf, Akihiro Mori, Chad L. Myers, Albertha J. M. Walhout Oct 2016

A Gene-Centered C. Elegans Protein-Dna Interaction Network Provides A Framework For Functional Predictions, Juan Fuxman Bass, Carles Pons, Lucie Kozlowski, John S. Reece-Hoyes, Shaleen Shrestha, Amy D. Holdorf, Akihiro Mori, Chad L. Myers, Albertha J. M. Walhout

Open Access Articles

Transcription factors (TFs) play a central role in controlling spatiotemporal gene expression and the response to environmental cues. A comprehensive understanding of gene regulation requires integrating physical protein-DNA interactions (PDIs) with TF regulatory activity, expression patterns, and phenotypic data. Although great progress has been made in mapping PDIs using chromatin immunoprecipitation, these studies have only characterized ~10% of TFs in any metazoan species. The nematode C. elegans has been widely used to study gene regulation due to its compact genome with short regulatory sequences. Here, we delineated the largest gene-centered metazoan PDI network to date by examining interactions between 90 ...


The Rna-Binding Protein Atx-2 Regulates Cytokinesis Through Par-5 And Zen-4, Megan M. Gnazzo, Eva-Maria E. Uhlemann, Alex R. Villarreal, Masaki Shirayama, Eddie G. Dominguez, Ahna R. Skop Oct 2016

The Rna-Binding Protein Atx-2 Regulates Cytokinesis Through Par-5 And Zen-4, Megan M. Gnazzo, Eva-Maria E. Uhlemann, Alex R. Villarreal, Masaki Shirayama, Eddie G. Dominguez, Ahna R. Skop

Open Access Articles

The spindle midzone harbors both microtubules and proteins necessary for furrow formation and the completion of cytokinesis. However, the mechanisms that mediate the temporal and spatial recruitment of cell division factors to the spindle midzone and midbody remain unclear. Here we describe a mechanism governed by the conserved RNA-binding protein ATX-2/Ataxin-2, which targets and maintains ZEN-4 at the spindle midzone. ATX-2 does this by regulating the amount of PAR-5 at mitotic structures, particularly the spindle, centrosomes, and midbody. Preventing ATX-2 function leads to elevated levels of PAR-5, enhanced chromatin and centrosome localization of PAR-5-GFP, and ultimately a reduction of ...


Adipocyte-Specific Hypoxia-Inducible Gene 2 Promotes Fat Deposition And Diet-Induced Insulin Resistance, Marina Distefano, Rachel J. Roth Flach, Ozlem Senol-Cosar, Laura V. Danai, Joseph V. Virbasius, Sarah M. Nicoloro, Juerg R. Straubhaar, Sezin Dagdeviren, Martin Wabitsch, Olga T. Gupta, Jason K. Kim, Michael P. Czech Sep 2016

Adipocyte-Specific Hypoxia-Inducible Gene 2 Promotes Fat Deposition And Diet-Induced Insulin Resistance, Marina Distefano, Rachel J. Roth Flach, Ozlem Senol-Cosar, Laura V. Danai, Joseph V. Virbasius, Sarah M. Nicoloro, Juerg R. Straubhaar, Sezin Dagdeviren, Martin Wabitsch, Olga T. Gupta, Jason K. Kim, Michael P. Czech

Open Access Articles

OBJECTIVE: Adipose tissue relies on lipid droplet (LD) proteins in its role as a lipid-storing endocrine organ that controls whole body metabolism. Hypoxia-inducible Gene 2 (Hig2) is a recently identified LD-associated protein in hepatocytes that promotes hepatic lipid storage, but its role in the adipocyte had not been investigated. Here we tested the hypothesis that Hig2 localization to LDs in adipocytes promotes adipose tissue lipid deposition and systemic glucose homeostasis.

METHOD: White and brown adipocyte-deficient (Hig2fl/fl x Adiponection cre+) and selective brown/beige adipocyte-deficient (Hig2fl/fl x Ucp1 cre+) mice were generated to investigate the role of Hig2 in ...