Autoinhibition of the Nuclease ARTEMIS is Mediated by a Physical Interaction between Its Catalytic and C-terminal Domains [Immunology]

January 12th, 2017 by Doris Niewolik, Ingrid Peter, Carmen Butscher, Klaus Schwarz

The nuclease ARTEMIS is essential for the development of B and T lymphocytes. It is required for opening DNA hairpins generated during antigen receptor gene assembly from variable (V), diversity (D) and joining (J) subgenic elements (V(D)J recombination). As a member of the non-homologous end joining pathway it is also involved in repairing a subset of pathological DNA double-strand breaks. Loss of ARTEMIS function therefore results in radiosensitive severe combined immunodeficiency (RS-SCID). The hairpin-opening activity is dependent on the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), which can bind to and phosphorylate ARTEMIS. The ARTEMIS C-terminus is dispensable for cellular V(D)J recombination and in vitro nuclease assays with C-terminally truncated ARTEMIS show DNA PKcs-independent hairpin-opening activity. Therefore it has been postulated that ARTEMIS is regulated via autoinhibition by its C-terminus. To obtain evidence for the autoinhibition model, we performed co-immunoprecipitation experiments with combinations of ARTEMIS mutants. We show that an N-terminal fragment comprising the catalytic domain can interact both with itself and with a C-terminal fragment. Amino acid exchanges N456A+S457A+E458Q in the C-terminus of full-length ARTEMIS resulted in unmasking of the N-terminus and in increased ARTEMIS activity in cellular V(D)J recombination assays. Mutations in ARTEMIS-deficient patients impaired the interaction with the C-terminus and also affected protein stability. The interaction between the N- and C-terminal domains was not DNA-PKcs dependent and phosphomimetic mutations in the C-terminal domain did not result in unmasking of the catalytic domain. Our experiments provide strong evidence that a physical interaction between the C-terminal and catalytic domains mediates ARTEMIS autoinhibition.

MraY–antibiotic complex reveals details of tunicamycin mode of action

January 9th, 2017 by Jonna K Hakulinen

Nature Chemical Biology 13, 265 (2017). doi:10.1038/nchembio.2270

Authors: Jonna K Hakulinen, Jenny Hering, Gisela Brändén, Hongming Chen, Arjan Snijder, Margareta Ek & Patrik Johansson

The rapid increase of antibiotic resistance has created an urgent need to develop novel antimicrobial agents. Here we describe the crystal structure of the promising bacterial target phospho-N-acetylmuramoyl–pentapeptide translocase (MraY) in complex with the nucleoside antibiotic tunicamycin. The structure not only reveals the mode of action of several related natural-product antibiotics but also gives an indication on the binding mode of the MraY UDP–MurNAc–pentapeptide and undecaprenyl-phosphate substrates.

  • Posted in Nat Chem Biol, Publications
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Visualizing the secondary and tertiary architectural domains of lncRNA RepA

January 9th, 2017 by Fei Liu

Nature Chemical Biology 13, 282 (2017). doi:10.1038/nchembio.2272

Authors: Fei Liu, Srinivas Somarowthu & Anna Marie Pyle

  • Posted in Nat Chem Biol, Publications
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Biomimetic spinning of artificial spider silk from a chimeric minispidroin

January 9th, 2017 by Marlene Andersson

Nature Chemical Biology 13, 262 (2017). doi:10.1038/nchembio.2269

Authors: Marlene Andersson, Qiupin Jia, Ana Abella, Xiau-Yeen Lee, Michael Landreh, Pasi Purhonen, Hans Hebert, Maria Tenje, Carol V Robinson, Qing Meng, Gustavo R Plaza, Jan Johansson & Anna Rising

Herein we present a chimeric recombinant spider silk protein (spidroin) whose aqueous solubility equals that of native spider silk dope and a spinning device that is based solely on aqueous buffers, shear forces and lowered pH. The process recapitulates the complex molecular mechanisms that dictate native spider silk spinning and is highly efficient; spidroin from one liter of bacterial shake-flask culture is enough to spin a kilometer of the hitherto toughest as-spun artificial spider silk fiber.

  • Posted in Nat Chem Biol, Publications
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Structural and functional insights into asymmetric enzymatic dehydration of alkenols

January 9th, 2017 by Bettina M Nestl

Nature Chemical Biology 13, 275 (2017). doi:10.1038/nchembio.2271

Authors: Bettina M Nestl, Christopher Geinitz, Stephanie Popa, Sari Rizek, Robert J Haselbeck, Rosary Stephen, Michael A Noble, Max-Philipp Fischer, Erik C Ralph, Hoi Ting Hau, Henry Man, Muhiadin Omar, Johan P Turkenburg, Stephen van Dien, Stephanie J Culler, Gideon Grogan & Bernhard Hauer

  • Posted in Nat Chem Biol, Publications
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Biochemical Validation of a Third Guanidine Riboswitch Class in Bacteria

January 6th, 2017 by Madeline E. Sherlock and Ronald R. Breaker

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Biochemistry
DOI: 10.1021/acs.biochem.6b01271

Duration Control of Protein Expression in Vivo by Light-Mediated Reversible Activation of Translation

January 4th, 2017 by Shinzi Ogasawara

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ACS Chemical Biology
DOI: 10.1021/acschembio.6b00684
  • Posted in ACS Chemical Biology, Publications
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A Photoactivatable Innate Immune Receptor for Optogenetic Inflammation

December 29th, 2016 by Brittany A. Moser and Aaron P. Esser-Kahn

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ACS Chemical Biology
DOI: 10.1021/acschembio.6b01012

β2-adrenergic receptor control of endosomal PTH receptor signaling via Gβγ

December 26th, 2016 by Frédéric G Jean-Alphonse

Nature Chemical Biology 13, 259 (2017). doi:10.1038/nchembio.2267

Authors: Frédéric G Jean-Alphonse, Vanessa L Wehbi, Jingming Chen, Masaki Noda, Juan M Taboas, Kunhong Xiao & Jean-Pierre Vilardaga

Cells express several G-protein-coupled receptors (GPCRs) at their surfaces, transmitting simultaneous extracellular hormonal and chemical signals into cells. A comprehensive understanding of mechanisms underlying the integrated signaling response induced by distinct GPCRs is thus required. Here we found that the β2-adrenergic receptor, which induces a short cAMP response, prolongs nuclear cAMP and protein kinase A (PKA) activation by promoting endosomal cAMP production in parathyroid hormone (PTH) receptor signaling through the stimulatory action of G protein Gβγ subunits on adenylate cyclase type 2.

  • Posted in Nat Chem Biol, Publications
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Orthogonal lipid sensors identify transbilayer asymmetry of plasma membrane cholesterol

December 26th, 2016 by Shu-Lin Liu

Nature Chemical Biology 13, 268 (2017). doi:10.1038/nchembio.2268

Authors: Shu-Lin Liu, Ren Sheng, Jae Hun Jung, Li Wang, Ewa Stec, Matthew J O'Connor, Seohyoen Song, Rama Kamesh Bikkavilli, Robert A Winn, Daesung Lee, Kwanghee Baek, Kazumitsu Ueda, Irena Levitan, Kwang-Pyo Kim & Wonhwa Cho

  • Posted in Nat Chem Biol, Publications
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