{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,8]],"date-time":"2026-03-08T06:57:55Z","timestamp":1772953075550,"version":"3.50.1"},"reference-count":24,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,2,25]],"date-time":"2021-02-25T00:00:00Z","timestamp":1614211200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiologic agent responsible for the recent coronavirus disease 2019 (COVID-19) pandemic. Productive SARS-CoV-2 infection relies on viral entry into cells expressing angiotensin-converting enzyme 2 (ACE2). Indeed, viral entry into cells is mostly mediated by the early interaction between the viral spike protein S and its ACE2 receptor. The S\/ACE2 complex is, thus, the first contact point between the incoming virus and its cellular target; consequently, it has been considered an attractive therapeutic target. To further characterize this interaction and the cellular processes engaged in the entry step of the virus, we set up various in silico, in vitro and in cellulo approaches that allowed us to specifically monitor the S\/ACE2 association. We report here a computational model of the SARS-CoV-2 S\/ACE2 complex, as well as its biochemical and biophysical monitoring using pulldown, AlphaLISA and biolayer interferometry (BLI) binding assays. This led us to determine the kinetic parameters of the S\/ACE2 association and dissociation steps. In parallel to these in vitro approaches, we developed in cellulo transduction assays using SARS-CoV-2 pseudotyped lentiviral vectors and HEK293T-ACE2 cell lines generated in-house. This allowed us to recapitulate the early replication stage of the infection mediated by the S\/ACE2 interaction and to detect cell fusion induced by the interaction. Finally, a cell imaging system was set up to directly monitor the S\/ACE2 interaction in a cellular context and a flow cytometry assay was developed to quantify this association at the cell surface. Together, these different approaches are available for both basic and clinical research, aiming to characterize the entry step of the original SARS-CoV-2 strain and its variants as well as to investigate the possible chemical modulation of this interaction. All these models will help in identifying new antiviral agents and new chemical tools for dissecting the virus entry step.<\/jats:p>","DOI":"10.3390\/v13030365","type":"journal-article","created":{"date-parts":[[2021,2,26]],"date-time":"2021-02-26T09:47:20Z","timestamp":1614332840000},"page":"365","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["In Silico, In Vitro and In Cellulo Models for Monitoring SARS-CoV-2 Spike\/Human ACE2 Complex, Viral Entry and Cell Fusion"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9117-0547","authenticated-orcid":false,"given":"Delphine","family":"Lapaillerie","sequence":"first","affiliation":[{"name":"Fundamental Microbiology and Pathogenicity Lab (MFP), UMR 5234 CNRS-University of Bordeaux, SFR TransBioMed, 33076 Bordeaux, France"}]},{"given":"Cathy","family":"Charlier","sequence":"additional","affiliation":[{"name":"IMPACT Platform \u201cInteractions Mol\u00e9culaires Puces ACTivit\u00e9s\u201d, UMR CNRS 6286 UFIP, Universit\u00e9 de Nantes, F-44000 Nantes, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9280-1838","authenticated-orcid":false,"given":"Henrique S.","family":"Fernandes","sequence":"additional","affiliation":[{"name":"UCIBIO@REQUIMTE, BioSIM -Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Professor Hern\u00e2ni Monteiro, 4200-319 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6560-5284","authenticated-orcid":false,"given":"Sergio F.","family":"Sousa","sequence":"additional","affiliation":[{"name":"UCIBIO@REQUIMTE, BioSIM -Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Alameda Professor Hern\u00e2ni Monteiro, 4200-319 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4623-0675","authenticated-orcid":false,"given":"Paul","family":"Lesbats","sequence":"additional","affiliation":[{"name":"Fundamental Microbiology and Pathogenicity Lab (MFP), UMR 5234 CNRS-University of Bordeaux, SFR TransBioMed, 33076 Bordeaux, France"}]},{"given":"Pierre","family":"Weigel","sequence":"additional","affiliation":[{"name":"IMPACT Platform \u201cInteractions Mol\u00e9culaires Puces ACTivit\u00e9s\u201d, UMR CNRS 6286 UFIP, Universit\u00e9 de Nantes, F-44000 Nantes, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0881-9224","authenticated-orcid":false,"given":"Alexandre","family":"Favereaux","sequence":"additional","affiliation":[{"name":"Interdisciplinary Institute for Neuroscience (IINS-CNRS UMR 5297), Centre Broca Nouvelle Aquitaine, 33076 Bordeaux, France"}]},{"given":"V\u00e9ronique","family":"Guyonnet-Duperat","sequence":"additional","affiliation":[{"name":"Vect\u2019UB, vectorology platform, INSERM US05\u2014CNRS UMS 3427-TBM-Core, Universit\u00e9 de Bordeaux, 33000 Bordeaux, France"}]},{"given":"Vincent","family":"Parissi","sequence":"additional","affiliation":[{"name":"Fundamental Microbiology and Pathogenicity Lab (MFP), UMR 5234 CNRS-University of Bordeaux, SFR TransBioMed, 33076 Bordeaux, France"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Boopathi, S., Poma, A.B., and Kolandaivel, P. 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