β-Arrestin/AP-2 Interaction in G Protein-coupled Receptor Internalization : IDENTIFICATION OF A β-ARRESTIN BINDING SITE IN β_2-ADAPTIN

Laporte, Ste´phane A.,Miller, William E.,Kim, Kyeong-Man,Caron, Marc G. 전남대학교 약품개발연구소 2002 약품개발연구지 Vol.11 No.-

β-Arrestins, proteins involved in the turn-off of G protein-coupled receptor (GPCR) activation, bind to the β_2-adaptin subunit of the clathrin adaptor AP-2. The interaction of β_2-adaptin with β-Arrestin involves critical arginine residues in the C-terminal domain of β-Arrestin and plays an important role in initiating clathrin-mediated endocytosis of the β_2-adrenergic receptor(β_2AR) (Laporte, S. A., Oakley, R. H., Holt, J. A., Barak, L. S., and Caron, M. G. (2000) J. Biol. Chem. 276, 23120-23126). However, the β-arrestin-binding site in β_2-adaptin has not been identified, and little is known about the role of β-arrestin/AP-2 interaction in the endocytosis of other GPCRs. Using in vitro binding assays, we have identified two glutamate residues (Glu-849 and Glu-902) in β_2-adaptin that are important in β-arrestin binding. These residues are located in the platform subdomain of the C terminus β_2-adaptin, where accessory/adapter endocytic proteins for other classes of receptors interact, distinct from the main site where clathrin interact. The functional significance of the β-arrestin/AP-2/clathrin complex in the endocytosis of GPCRs such as the β_2AR and vasopressin type Ⅱ receptor was evaluated using mutant constructs of the β_2-adaptin C terminus containing either the clathrin and the β-arrestin binding domains or the β-arrestin-binding domain alone. When expressed in human embryonic kidney 293 cells, both constructs acted as dominant negatives inhibiting the agonist-induced internalization of the β_2AR and the vasopressin type Ⅱ receptor. In addition, although the β_2-adaptin construct containing both the clathrin and β-arrestin binding domains was able to block the endocytosis of transferrin receptors, a β_2-adaptin construct capable of assoociating with β-arrestin but lacking its high affinity clathrin interaction did not interfere with transferrin receptor endocytosis. These results suggest that the interaction of β-arrestin with β_2-adaptin represents a selective endocytic trigger for several members of the GPCR family.

ISG15: leading a double life as a secreted molecule

Dusan Bogunovic,Ste´phanie Boisson-Dupuis,Jean-Laurent Casanova 생화학분자생물학회 2013 Experimental and molecular medicine Vol.45 No.4

ISG15 is a well-known intracellular ubiquitin-like molecule involved in ISGylation. However, a recent study has revived the notion first put forward two decades ago that ISG15 is also a secreted molecule. Human neutrophils, monocytes and lymphocytes can release ISG15, even though this protein has no detectable signal peptide sequence. ISG15 has also been found in the secretory granules of granulocytes. The mechanism underlying ISG15 secretion is unknown. Secreted ISG15 acts on at least T and natural killer (NK) lymphocytes, in which it induces interferon (IFN)-c production. However, the mechanism by which ISG15 stimulates these cells also remains unclear. ISG15 and IFN-c seem to define an innate circuit that operates preferentially, but not exclusively, between granulocytes and NK cells. Inherited ISG15 deficiency is associated with severe mycobacterial disease in both mice and humans. This infectious phenotype probably results from the lack of secreted ISG15,because patients and mice with other inborn errors of IFN-c immunity also display mycobacterial diseases. In addition to raising mechanistic issues, the studies described here pave the way for clinical studies of various aspects, ranging from the use of recombinant ISG15 in patients with infectious diseases to the use of ISG15-blocking agents in patients with inflammatory diseases.

Soy Intake Since the Prepubertal Age May Contribute to the Pathogenesis of Endometriosis in Adulthood

Marie Alfrede Mvondo,Jessica Darelle Ekenfack,Ste´phane Minko Essono,Harding Saah Namekong,Charline Florence Awounfack,Matthias W. Laschke,Dieudonne´ Njamen 한국식품영양과학회 2019 Journal of medicinal food Vol.22 No.6

High prevalence of endometriosis was reported in Asian women as a result of their traditionally high intake of soy foods during infancy. Soy is widely used in infant feeding after weaning from breast milk or cow milk. This study thus aimed to determine to what extent soy intake before puberty may contribute to the development of endometriosis. For this purpose, immature (6-week old) female rats were fed with various soy formulas (0%, 10%, 20%, 30%, 40%, 50%, and 60%). Normal control animals were fed with a soy-free diet. At 13 weeks of age, animals (except the normal control) underwent a transplantation surgery to establish endometriosis. Estradiol valerate and oxytocin were used to induce pelvic pain. Endometrial implant levels of glutathione (GSH) and malondialdehyde (MDA) allowed estimating tissue oxidative status. Physiological ovarian function was assessed by histological analysis of ovaries. Results showed that soy-fed animals grew faster than animals receiving a soy-free diet (P < .001). In animals supplemented with more than 10% of soy, the intensity of pelvic pain increased (P < .001) as well as the volume of ectopic foci. In addition, tissue levels of MDA and GSH increased (P < .001). The ovarian function was altered and the number of luteinized unruptured follicles increased. In conclusion, although animals supplemented with soy at the prepubertal stage displayed a good growth performance, regular soy consumption may promote the development and progress of endometriosis in adulthood, especially when soy content in food is more than 10%.

Protonation Dependent Topological Dichotomy of Core Modified Hexaphyrins: Synthesis, Characterization, and Excited State Dynamics

Mallick, Abhijit,Oh, Juwon,Majewski, Marcin A.,Stę,pień,, Marcin,Kim, Dongho,Rath, Harapriya American Chemical Society etc. 2017 Journal of organic chemistry Vol.82 No.1

<P>Two hitherto unknown core modified hexaphyrin analogues have been synthesized and characterized where the conformational dynamics of these macrocycles in the free base form is achieved by the rotation of thienothiophene units. Further unique property of these macrocycles is the Hiickel-Mobius topological switching. The thermodynamic equilibrium and kinetics of the interconversion leading to Htickel-Mobius switches have been triggered by external stimuli, such as protonation and/or temperature. We have provided a thorough solution-state spectroscopic characterization, solidstate structural evidence combined with in-depth theoretical calculations to investigate the crucial factors involved in such interconversion between Huckel and Mobius topologies for these hexaphyrins which will be useful in designing future new members to expanded porphyrin chemistry.</P>

Perylenediimide-Based Donor–Acceptor Dyads and Triads: Impact of Molecular Architecture on Self-Assembling Properties

Schwartz, Pierre-Olivier,Biniek, Laure,Zaborova, Elena,Heinrich, Benoî,t,Brinkmann, Martin,Leclerc, Nicolas,Mé,ry, Sté,phane American Chemical Society 2014 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.136 No.16

<P>Perylenediimide-based donor–acceptor co-oligomers are particularly attractive in plastic electronics because of their unique electro-active properties that can be tuned by proper chemical engineering. Herein, a new class of co-oligomers has been synthesized with a dyad structure (AD) or a triad structure (DAD and ADA) in order to understand the correlations between the co-oligomer molecular architecture and the structures formed by self-assembly in thin films. The acceptor block A is a perylene tetracarboxyl diimide (PDI), whereas the donor block D is made of a combination of thiophene, fluorene, and 2,1,3-benzothiadiazole derivatives. D and A blocks are linked by a short and flexible ethylene spacer to ease self-assembling in thin films. Structural studies using small and wide X-ray diffraction and transmission electron microscopy demonstrate that AD and ADA lamellae are made of a double layer of co-oligomers with overlapping and strongly π-stacked PDI units because the sectional area of the PDI is about half that of the donor block. These structural models allow rationalizing the absence of organization for the DAD co-oligomer and therefore to draw general rules for the design of PDI-based dyads and triads with proper self-assembling properties of use in organic electronics.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2014/jacsat.2014.136.issue-16/ja4129108/production/images/medium/ja-2013-129108_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja4129108'>ACS Electronic Supporting Info</A></P>

Creation of Magnetic Skyrmion Bubble Lattices by Ultrafast Laser in Ultrathin Films

Je, Soong-Geun,Vallobra, Pierre,Srivastava, Titiksha,Rojas-Sá,nchez, Juan-Carlos,Pham, Thai Ha,Hehn, Michel,Malinowski, Gregory,Baraduc, Claire,Auffret, Sté,phane,Gaudin, Gilles,Mangin, St American Chemical Society 2018 NANO LETTERS Vol.18 No.11

<P>Magnetic skyrmions are topologically nontrivial spin textures which hold great promise as stable information carriers in spintronic devices at the nanoscale. One of the major challenges for developing novel skyrmion-based memory and logic devices is fast and controlled creation of magnetic skyrmions at ambient conditions. Here we demonstrate controlled generation of skyrmion bubbles and skyrmion bubble lattices from a ferromagnetic state in sputtered ultrathin magnetic films at room temperature by a single ultrafast (35 fs) laser pulse. The skyrmion bubble density increases with the laser fluence, and it finally becomes saturated, forming disordered hexagonal lattices. Moreover, we present that the skyrmion bubble lattice configuration leads to enhanced topological stability as compared to isolated skyrmions, suggesting its promising use in data storage. Our findings shed light on the optical approach to the skyrmion bubble lattice in commonly accessible materials, paving the road toward the emerging skyrmion-based memory and synaptic devices.</P> [FIG OMISSION]</BR>

Model based engineering of <i>Pichia pastoris</i> central metabolism enhances recombinant protein production

Nocon, Justyna,Steiger, Matthias G.,Pfeffer, Martin,Sohn, Seung Bum,Kim, Tae Yong,Maurer, Michael,Rußmayer, Hannes,Pflü,gl, Stefan,Ask, Magnus,Haberhauer-Troyer, Christina,Ortmayr, Karin,Hann, Ste Academic Press 2014 Metabolic engineering Vol.24 No.-

<▼1><P>The production of recombinant proteins is frequently enhanced at the levels of transcription, codon usage, protein folding and secretion. Overproduction of heterologous proteins, however, also directly affects the primary metabolism of the producing cells. By incorporation of the production of a heterologous protein into a genome scale metabolic model of the yeast <I>Pichia pastoris</I>, the effects of overproduction were simulated and gene targets for deletion or overexpression for enhanced productivity were predicted. Overexpression targets were localized in the pentose phosphate pathway and the TCA cycle, while knockout targets were found in several branch points of glycolysis. Five out of 9 tested targets led to an enhanced production of cytosolic human superoxide dismutase (hSOD). Expression of bacterial β-glucuronidase could be enhanced as well by most of the same genetic modifications. Beneficial mutations were mainly related to reduction of the NADP/H pool and the deletion of fermentative pathways. Overexpression of the hSOD gene itself had a strong impact on intracellular fluxes, most of which changed in the same direction as predicted by the model. <I>In vivo</I> fluxes changed in the same direction as predicted to improve hSOD production. Genome scale metabolic modeling is shown to predict overexpression and deletion mutants which enhance recombinant protein production with high accuracy.</P></▼1><▼2><P><B>Highlights</B></P><P>•<P>Recombinant protein production in <I>P. pastoris</I> affects the central metabolism.</P>•<P>A genome scale metabolic model can predict these metabolic flux changes.</P>•<P>Mutations in central metabolic genes enhanced recombinant protein yield up to 40%.</P>•<P>These beneficial mutations were predicted by the metabolic model with high accuracy.</P></P></▼2>

Synergy of glucose and growth hormone signalling in islet cells through ICA512 and STAT5

Mziaut, Hassan,Trajkovski, Mirko,Kersting, Stephan,Ehninger, Armin,Altkrü,ger, Anke,Lemaitre, Ré,gis P.,Schmidt, Darja,Saeger, Hans-Detlev,Lee, Myung-Shik,Drechsel, David N.,Mü,ller, Ste Nature Publishing Group 2006 Nature cell biology Vol.8 No.5

Nutrients and growth hormones promote insulin production and the proliferation of pancreatic β-cells. An imbalance between ever-increasing metabolic demands and insulin output causes diabetes. Recent evidence indicates that β-cells enhance insulin gene expression depending on their secretory activity. This signalling pathway involves a catalytically inactive receptor tyrosine phosphatase, ICA512, whose cytoplasmic tail is cleaved on glucose-stimulated exocytosis of insulin secretory granules and then moves into the nucleus, where it upregulates insulin transcription. Here, we show that the cleaved cytosolic fragment of ICA512 enhances the transcription of secretory granule genes (including its own gene) by binding to tyrosine phosphorylated signal transducers and activators of transcription (STAT) 5 and preventing its dephosphorylation. Sumoylation of ICA512 by the E3 SUMO ligase PIASy, in turn, may reverse this process by decreasing the binding of ICA512 to STAT5. These findings illustrate how the exocytosis of secretory granules, through a retrograde pathway that sustains STAT activity, converges with growth hormone signalling to induce adaptive changes in β-cells in response to metabolic demands.

Characterization of uncertainties in atmospheric trace gas inversions using hierarchical Bayesian methods

Ganesan, A. L.,Rigby, M.,Zammit-Mangion, A.,Manning, A. J.,Prinn, R. G.,Fraser, P. J.,Harth, C. M.,Kim, K.-R.,Krummel, P. B.,Li, S.,Mü,hle, J.,O&,apos,Doherty, S. J.,Park, S.,Salameh, P. K.,Ste Copernicus GmbH 2014 Atmospheric chemistry and physics Vol.14 No.8

<P>Abstract. We present a hierarchical Bayesian method for atmospheric trace gas inversions. This method is used to estimate emissions of trace gases as well as 'hyper-parameters' that characterize the probability density functions (PDFs) of the a priori emissions and model-measurement covariances. By exploring the space of 'uncertainties in uncertainties', we show that the hierarchical method results in a more complete estimation of emissions and their uncertainties than traditional Bayesian inversions, which rely heavily on expert judgment. We present an analysis that shows the effect of including hyper-parameters, which are themselves informed by the data, and show that this method can serve to reduce the effect of errors in assumptions made about the a priori emissions and model-measurement uncertainties. We then apply this method to the estimation of sulfur hexafluoride (SF6) emissions over 2012 for the regions surrounding four Advanced Global Atmospheric Gases Experiment (AGAGE) stations. We find that improper accounting of model representation uncertainties, in particular, can lead to the derivation of emissions and associated uncertainties that are unrealistic and show that those derived using the hierarchical method are likely to be more representative of the true uncertainties in the system. We demonstrate through this SF6 case study that this method is less sensitive to outliers in the data and to subjective assumptions about a priori emissions and model-measurement uncertainties than traditional methods. </P>

A p53/miRNA-34 axis regulates Snail1-dependent cancer cell epithelial–mesenchymal transition

Kim, Nam Hee,Kim, Hyun Sil,Li, Xiao-Yan,Lee, Inhan,Choi, Hyung-Seok,Kang, Shi Eun,Cha, So Young,Ryu, Joo Kyung,Yoon, Dojun,Fearon, Eric R.,Rowe, R. Grant,Lee, Sanghyuk,Maher, Christopher A.,Weiss, Ste The Rockefeller University Press 2011 The Journal of cell biology Vol.195 No.3

<▼1><P>Expression of the essential EMT inducer Snail1 is inhibited by miR-34 through a p53-dependent regulatory pathway.</P></▼1><▼2><P>Snail1 is a zinc finger transcriptional repressor whose pathological expression has been linked to cancer cell epithelial–mesenchymal transition (EMT) programs and the induction of tissue-invasive activity, but pro-oncogenic events capable of regulating Snail1 activity remain largely uncharacterized. Herein, we demonstrate that p53 loss-of-function or mutation promotes cancer cell EMT by de-repressing Snail1 protein expression and activity. In the absence of wild-type p53 function, Snail1-dependent EMT is activated in colon, breast, and lung carcinoma cells as a consequence of a decrease in miRNA-34 levels, which suppress Snail1 activity by binding to highly conserved 3′ untranslated regions in Snail1 itself as well as those of key Snail1 regulatory molecules, including β-catenin, LEF1, and Axin2. Although p53 activity can impact cell cycle regulation, apoptosis, and DNA repair pathways, the EMT and invasion programs initiated by p53 loss of function or mutation are completely dependent on Snail1 expression. These results identify a new link between p53, miR-34, and Snail1 in the regulation of cancer cell EMT programs.</P></▼2>