37 research outputs found
Structural and functional characterization of rapamycin-resistant TORC2
No full textTORC2 is nucleated by Target of Rapamycin (TOR), a protein kinase of the phosphatidylinositol 3-kinase-related kinase (PIKK) family. TOR kinases are validated drug targets which can be inhibited by rapamycin, facilitating elucidation of TORC1 signaling. TORC2 cannot be inhibited by rapamycin, and the lack of specific inhibitors has impeded progress in understanding the functions of this essential complex. The EM reconstruction revealed a rhomboid shape with C2 pseudo-symmetry and a prominent central cavity. We found that the TORC2-specific subunit Avo3 is proximal to the rapamycin binding domain of Tor2. Building on this observation, we successfully engineered a yeast strain in which TORC2, but not TORC1, is inhibited by rapamycin. We leveraged this unique tool to study TORC2 function and regulation, demonstrating that acute TORC2 inhibition abolishes actin polarization and leads to cell-cycle arrest
HEAR! HEaR! Voices of Canadian Women
No full textWhat difference can women’s voices make? This is the question posed by Shari Graydon, author, speaker, and founder of Informed Opinions, a national initiative aimed at amplifying women’s voices in Canadian public discourse. It is the question explored in HEAR! HEaR! Voices of Canadian Women as well. Contributors to this collection of papers were participants in a pair of conferences, “Discourse and Dynamics: Canadian Women as Public Intellectuals” and “Speaking Her Mind: Canadian Women and Public Presence,” that focussed on the multitudinous but often muffled voices of women in Canada and the intellectual import of their contributions. Speakers included writers, scientists, journalists, social workers, musicians, and academics—both established and emerging scholars. Together on panels and in paper presentations they confronted the under-representation of women’s voices in Canada from a wide variety of perspectives, backgrounds, professions, and pursuits.type of work: book**Please visit the accompanying website at https://speakinghermind.ca/ for more information.**
Introduction: Audibly Laudable: Voices of Canadian Women / Aritha van Herk & Christl Verduyn -- Refiguring the Public Intellectual: Lessons from Life Stories by Feminists in the Faculty Body / Wendy Robbins -- Who Gets to Be a Public Intellectual in Canada? / Iga Mergler & Neil McLaughlin -- Four Contemporary Canadian Women Intellectuals Negotiate the Challenges of Public Sphere Witnessing: Dionne Brand, Samantha Nutt, Sheila Watt-Cloutier, and Janice Williamson / Diana Brydon -- Stranger Sociability: Lisa Robertson as Counterpublic Intellectual / Heather Milne -- Is There a Canadian Uncle Tom’s Cabin? Canadian Women Writers and Social Change / Carole Gerson -- "Speaking Out": Gwethalyn Graham’s Non-Fiction / Galletly -- Idola Saint-Jean and Flora MacDonald Denison: Two Feminist Intellectuals in French and English Canada / Sarah Spear -- Speaking Your Mind, or Not: The Judicial Careers of Police Magistrates Emily Murphy and Alice Jane Jamieson, 1916-1932 / Mélanie Methot -- Speaking from South Africa: E. Maud Graham, Florence Randal, and the South African War / Bridgette Brown -- Margaret Gould (1900-1981): Social Worker, Social Critic, Public Intellectual / Marjorie Johnstone -- Public (Lending) Rights: Women’s Advocacy in The Writers’ Union of Canada / Erin Raml
Amino Acid Signaling in High Definition
No full textIn this issue of Structure, Zhang and colleagues present the structure of the Ego3 dimer, demonstrating that dimerization is an obligate prerequisite in amino acid-induced TORC1 activation
TORC2 Structure and Function
No full textThe target of rapamycin (TOR) kinase functions in two multiprotein complexes, TORC1 and TORC2. Although both complexes are evolutionarily conserved, only TORC1 is acutely inhibited by rapamycin. Consequently, only TORC1 signaling is relatively well understood; and, at present, only mammalian TORC1 is a validated drug target, pursued in immunosuppression and oncology. However, the knowledge void surrounding TORC2 is dissipating. Acute inhibition of TORC2 with small molecules is now possible and structural studies of both TORC1 and TORC2 have recently been reported. Here we review these recent advances as well as observations made from tissue-specific mTORC2 knockout mice. Together these studies help define TORC2 structure-function relationships and suggest that mammalian TORC2 may one day also become a bona fide clinical target
A second DNA binding site on RFC facilitates clamp loading at gapped or nicked DNA
No full textClamp loaders place circular sliding clamp proteins onto DNA so that clamp-binding partner proteins can synthesize, scan, and repair the genome. DNA with nicks or small single-stranded gaps are common clamp-loading targets in DNA repair, yet these substrates would be sterically blocked given the known mechanism for binding of primer-template DNA. Here, we report the discovery of a second DNA binding site in the yeast clamp loader replication factor C (RFC) that aids in binding to nicked or gapped DNA. This DNA binding site is on the external surface and is only accessible in the open conformation of RFC. Initial DNA binding at this site thus provides access to the primary DNA binding site in the central chamber. Furthermore, we identify that this site can partially unwind DNA to create an extended single-stranded gap for DNA binding in RFC's central chamber and subsequent ATPase activation. Finally, we show that deletion of the BRCT domain, a major component of the external DNA binding site, results in defective yeast growth in the presence of DNA damage where nicked or gapped DNA intermediates occur. We propose that RFC's external DNA binding site acts to enhance DNA binding and clamp loading, particularly at DNA architectures typically found in DNA repair
Cloning, expression, purification, and characterisation of the HEAT-repeat domain of TOR from the thermophilic eukaryote Chaetomium thermophilum
No full textInternational audienc
Une Voix Féminine Précoce au Théâtre Québécois: Cocktail (1935) d'Yvette Ollivier Mercier-Gouin
No full textEn 1935 la pièce Cocktail d'Yvette Ollivier Mercier-Gouin a été réclamée sur la scène théâtrale québécoise. Le public de l'époque semblait y reconnaître sa première grande pièce nationale. Comment expliquer alors l'obscurité dans laquelle sont sombrées pièce et auteure à partir de 1940? Une lecture contemporaine de la pièce dégage une thématique qui devait attendre, pour être approfondie, une perspective littéraire et critique féministe.
Yvette Ollivier Mercier-Gouin's 1935 play Cocktail was hailed by Quebec audiences of the time as a first major national success. After 1940, however, neither play nor author received much critical attention. The play profits from a rereading today front the perspective of feminist literary criticism
The Seventh Day in Genesis 2:2–3 and the Change from Kingship to Sabbath
No full textThe priestly texts in the Pentateuch depict the Sabbath as the foundational principle of order. The present article argues that in the priestly world view the Sabbath takes the place normally occupied by the institution of kingship. In the priestly redefinition of order, the central focus no longer is on military power, but on holiness. Instead of having a king as his earthly representative, Yhwh chooses Israel. Furthermore, the tight bond between God and Israel is not demonstrated on the battlefield, but becomes manifest in their joint venture of keeping the Sabbath as a holy day. God reveals this sublime principle of order to Israel, so that Israel as his representative will continue his work and protect the creational order. By living according to the Sabbatical order— in which the Sabbath serves as the paragon for the entire priestly Torah— the people of Israel, as though they were all kings, form the living image of God on earth. Gen 1:1–2:3, although often read as a universal story, on closer examination appears to be full of Israelite specifics. The author of the P-creation account never aimed to write an objective, universal treatise on the creation of the world. The purpose of Gen 1:1–2:3 was to enshrine Israel’s distinctive, Sabbatical, way of life within the creational order
Effective mismatch repair depends on timely control of PCNA retention on DNA by the Elg1 complex
No full textACKNOWLEDGEMENTS We thank Richard Kolodner and Eric Alani for strains and plasmids. We thank Anne Donaldson, Alexander Lorenz and Catherine Johnson from University of Aberdeen for careful reading of the manuscript. We thank Annabelle Duff and Veronika Petrova for assisting with the mutation rate assays, and Duru Cosar for assisting with crystal structure analysis. We appreciate assistance from staff of the Microscopy and Histology Core Facility and the qPCR facility at the University of Aberdeen. FUNDING Medical Research Council (MRC) Career Development Fellowship [L019698/1 to T.K.]; American Cancer Society Research Scholar Award [Grant #440685 to B.A.K.]; National Institute of General Medical Sciences [R01 GM127776 to B.A.K.]; National Institutes of Health grant [R01 GM106060 to V.L.]. Swiss National Science Foundation Postdoc Mobility Fellowship (to C.G.). Funding for open access charge: Medical Research Council via University of Aberdeen Open Access Fund.Peer reviewe
Effective mismatch repair depends on timely control of PCNA retention on DNA by the Elg1 complex
No full textProliferating cell nuclear antigen (PCNA) is a sliding clamp that acts as a central co-ordinator for mismatch repair (MMR) as well as DNA replication. Loss of Elg1, the major subunit of the PCNA unloader complex, causes over-accumulation of PCNA on DNA and also increases mutation rate, but it has been unclear if the two effects are linked. Here we show that timely removal of PCNA from DNA by the Elg1 complex is important to prevent mutations. Although premature unloading of PCNA generally increases mutation rate, the mutator phenotype of elg1Delta is attenuated by PCNA mutants PCNA-R14E and PCNA-D150E that spontaneously fall off DNA. In contrast, the elg1Delta mutator phenotype is exacerbated by PCNA mutants that accumulate on DNA due to enhanced electrostatic PCNA-DNA interactions. Epistasis analysis suggests that PCNA over-accumulation on DNA interferes with both MMR and MMR-independent process(es). In elg1Delta, over-retained PCNA hyper-recruits the Msh2-Msh6 mismatch recognition complex through its PCNA-interacting peptide motif, causing accumulation of MMR intermediates. Our results suggest that PCNA retention controlled by the Elg1 complex is critical for efficient MMR: PCNA needs to be on DNA long enough to enable MMR, but if it is retained too long it interferes with downstream repair steps
