{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T05:25:36Z","timestamp":1790573136690,"version":"4.1.0"},"reference-count":51,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2021,8,26]],"date-time":"2021-08-26T00:00:00Z","timestamp":1629936000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Medical Faculty, Ruhr-University Bochum, FoRUM grant","award":["F1014-2021"],"award-info":[{"award-number":["F1014-2021"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is the causative agent of the COVID19 pandemic. The SARS-CoV-2 genome encodes for a small accessory protein termed Orf9b, which targets the mitochondrial outer membrane protein TOM70 in infected cells. TOM70 is involved in a signaling cascade that ultimately leads to the induction of type I interferons (IFN-I). This cascade depends on the recruitment of Hsp90-bound proteins to the N-terminal domain of TOM70. Binding of Orf9b to TOM70 decreases the expression of IFN-I; however, the underlying mechanism remains elusive. We show that the binding of Orf9b to TOM70 inhibits the recruitment of Hsp90 and chaperone-associated proteins. We characterized the binding site of Orf9b within the C-terminal domain of TOM70 and found that a serine in position 53 of Orf9b and a glutamate in position 477 of TOM70 are crucial for the association of both proteins. A phosphomimetic variant Orf9bS53E showed drastically reduced binding to TOM70 and did not inhibit Hsp90 recruitment, suggesting that Orf9b\u2013TOM70 complex formation is regulated by phosphorylation. Eventually, we identified the N-terminal TPR domain of TOM70 as a second binding site for Orf9b, which indicates a so far unobserved contribution of chaperones in the mitochondrial targeting of the viral protein.<\/jats:p>","DOI":"10.3390\/ijms22179233","type":"journal-article","created":{"date-parts":[[2021,8,26]],"date-time":"2021-08-26T09:27:57Z","timestamp":1629970077000},"page":"9233","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":42,"title":["Phosphorylation of SARS-CoV-2 Orf9b Regulates Its Targeting to Two Binding Sites in TOM70 and Recruitment of Hsp90"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3231-6312","authenticated-orcid":false,"given":"Lukas","family":"Brandherm","sequence":"first","affiliation":[{"name":"Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44801 Bochum, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonio Mario","family":"Koba\u0161","sequence":"additional","affiliation":[{"name":"Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44801 Bochum, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7707-2040","authenticated-orcid":false,"given":"Mara","family":"Kl\u00f6hn","sequence":"additional","affiliation":[{"name":"Department of Molecular & Medical Virology, Ruhr-University Bochum, 44801 Bochum, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8790-0022","authenticated-orcid":false,"given":"Yannick","family":"Br\u00fcggemann","sequence":"additional","affiliation":[{"name":"Department of Molecular & Medical Virology, Ruhr-University Bochum, 44801 Bochum, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephanie","family":"Pfaender","sequence":"additional","affiliation":[{"name":"Department of Molecular & Medical Virology, Ruhr-University Bochum, 44801 Bochum, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1219-2623","authenticated-orcid":false,"given":"Joachim","family":"Rassow","sequence":"additional","affiliation":[{"name":"Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44801 Bochum, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sebastian","family":"Kreimendahl","sequence":"additional","affiliation":[{"name":"Institute for Biochemistry and Pathobiochemistry, Ruhr-University Bochum, 44801 Bochum, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,26]]},"reference":[{"key":"ref_1","first-page":"1","article-title":"Tracking the international spread of SARS-CoV-2 lineages B.1.1.7 and B.1.351\/501Y-V2 [version 1; peer review: 3 approved]","volume":"6","author":"Toole","year":"2021","journal-title":"Wellcome Open Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3055","DOI":"10.1126\/science.abg3055","article-title":"Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England","volume":"372","author":"Davies","year":"2021","journal-title":"Science"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1038\/s41586-021-03426-1","article-title":"Increased mortality in community-tested cases of SARS-CoV-2 lineage B.1.1.7","volume":"593","author":"Davies","year":"2021","journal-title":"Nature"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1038\/s41586-021-03470-x","article-title":"Assessing transmissibility of SARS-CoV-2 lineage B.1.1.7 in England","volume":"593","author":"Volz","year":"2021","journal-title":"Nature"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1","DOI":"10.2807\/1560-7917.ES.2021.26.16.2100348","article-title":"Characteristics of SARS-CoV-2 variants of concern B.1.1.7, B.1.351 or P.1: Data from seven EU\/EEA countries, weeks 38\/2020 to 10\/2021","volume":"26","author":"Funk","year":"2021","journal-title":"Eurosurveillance"},{"key":"ref_6","unstructured":"Horby, A.P., Bell, I., Breuer, J., Cevik, M., Challen, R., Davies, N., Dabrera, G., Edmunds, J., Ferguson, N., and Funk, S. 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