A SARS-CoV-2 protein interaction map reveals targets for drug repurposing

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 2.3 million people, killed over 160,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven clinical efficacy, nor are there vaccines for its prevention, and these efforts are hampered by limited knowledge of the molecular details of SARS-CoV-2 infection. To address this, we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19

Woven Shades of Green : An Anthology of Irish Nature Literature

Woven Shades of Green is an annotated selection of literature from authors who focus on the natural world and the beauty of Ireland. The anthology begins with the Irish monks and their largely anonymous nature poetry, written at a time when Ireland was heavily forested. A section follows devoted to the changing Irish landscape, through both deforestation and famine, including the nature poetry of William Allingham, James Clarence Mangan, essays from Thomas Gainford and William Thackerary, and novel excerpts from William Carleton and Emily Lawless. The anthology then turns to the nature literature of the Irish Literary Revival, including Yeats and Synge, but also the poetry of many others, and an excerpt from George Moore’s novel The Lake. Part four of the anthology shifts to modern Irish nature poetry, beginning with Patrick Kavanaugh, and continuing with late twentieth-century, early twenty-first-century poetry of Seamus Heaney, Eavan Boland, and others. Finally, the anthology concludes with a section on various Irish naturalist writers, and the unique prose and philosophical nature writing of John Moriarty, followed by a comprehensive list of environmental organizations in Ireland, which seek to preserve the natural beauty of this unique country. Published by Bucknell University Press. Distributed worldwide by Rutgers University Press.https://digitalcommons.bucknell.edu/bucknell-press/1024/thumbnail.jp

Defining Sec61 client sensitivity using substrate-selective Sec61 modulators

One third of the human proteome relies on the Sec61 translocon for proper folding and function. Each Sec61 client has a unique signal peptide or signal anchor, which plays an essential role in promoting its translocation into the endoplasmic reticulum. Cotransins are cyclic depsipeptides that inhibit the biogenesis of a subset of secreted and membrane proteins by preventing cotranslational translocation into the endoplasmic reticulum. Sensitivity to cotransins is determined by the protein’s N-terminal signal peptide or signal anchor, which intercalates into the lateral gate of Sec61 to initiate translocation. However, it has been difficult to predict Sec61 client sensitivity to cotransins due to the large diversity of signal peptides and signal anchors and the lack of high throughput assays to effectively survey all predicted human Sec61 clients. We developed a fluorescence-based reporter system with a library of 3880 human (3212) and mouse (668) signal peptides to interrogate which Sec61 clients are most affected by cotransin analogs. This pooled-cell screening platform allowed us to profile two cotransins with distinct effects on cancer cells, KZR-9873 and KZR-8445. We identified a total of 665 sensitive signal peptides, most of which were previously not known to be sensitive to cotransins. Among several validated targets, we discovered that the oncoprotein HER3, a coreceptor for HER2, is preferentially inhibited by the more selective cotransin, KZR-9873. Comparison of the human and mouse signal peptide paralogs within the library revealed a position-dependent role for Arg and Lys in conferring cotransin sensitivity. Our screening platform revealed distinct signal peptide sequence determinants that confer sensitivity to cotransins. We used mass spectrometry to profile the effects of KZR-9873 and KZR-8445 on endogenous proteins in three cancer cell lines, CAL27, BxPC3 and SW48 cells. This approach allowed us to interrogate Sec61 client sensitivity beyond SP-containing proteins, since type II and multi-spanning membrane proteins are understudied with respect to their potential cotransin sensitivity. Of the Sec61 clients identified across the three cell lines, there were 360 KZR-9873-sensitive and 659 KZR-8445-sensitive Sec61 clients. We identified a total of 51 and 81 type II membrane proteins that were sensitive to KZR-9873 and KZR-8445, respectively. In addition, we identified 34 and 45 multi-spanning N-cyt membrane proteins that were sensitive to KZR-9873 and KZR-8445, respectively. Our proteomic approach showed that cotransins can inhibit the biogenesis of proteins that utilize the lateral gate of Sec61 to initiate cotranslational membrane insertion