Class I fusion
https://www.annualreviews.org/doi/10.1146/annurev-cellbio-101512-122422?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed
https://www.cell.com/cell/pdf/S0092-8674(18)30231-9.pdf
https://www.nature.com/articles/nrmicro1326
https://www.annualreviews.org/doi/pdf/10.1146/annurev-virology-111821-093413