Miguel Ángel Cuesta-Geijo, Isabel García-Dorival, Ana del Puerto, Jesús Urquiza, Inmaculada Galindo, Lucía Barrado-Gil, Fátima Lasala, Ana Cayuela, Carlos Oscar S. Sorzano, Carmen Gil, Rafael Delgado, Covadonga Alonso, La Caixa, Ministerio de Ciencia e Innovación (España), Instituto de Salud Carlos III, European Commission, Cuesta-Geijo, Miguel Ángel [0000-0003-4694-1968], García-Dorival, Isabel [0000-0002-5654-5662], Puerto, Ana del [0000-0002-5119-6395], Urquiza, Jesús [0000-0002-7870-4580], Galindo, Immaculada [0000-0001-8257-9797], Barrado-Gil, Lucía [0000-0002-1053-2997], Lasala, Fátima [0000-0001-8183-1866], Sorzano, Carlos Óscar S. [0000-0002-9473-283X], Gil, Carmen [0000-0002-3882-6081], Delgado, Rafael [0000-0002-6912-4736], Alonso, Covandoga [0000-0002-0862-6177], Cuesta-Geijo, Miguel Ángel, García-Dorival, Isabel, Puerto, Ana del, Urquiza, Jesús, Galindo, Immaculada, Barrado-Gil, Lucía, Lasala, Fátima, Sorzano, Carlos Óscar S., Gil, Carmen, Delgado, Rafael, and Alonso, Covandoga
28 p.-7 fig.-- Departamento de Biotecnología., African swine fever virus (ASFV) infectious cycle starts with the viral adsorption and entry into the host cell. Then, the virus is internalized via clathrin/dynamin mediated endocytosis and macropinocytosis. Similar to other viruses, ASF virion is then internalized and incorporated into the endocytic pathway. While the endosomal maturation entails luminal acidification, the decrease in pH acts on the multilayer structure of the virion dissolving the outer capsid. Upon decapsidation, the inner viral membrane is exposed to interact with the limiting membrane of the late endosome for fusion. Viral fusion is then necessary for the egress of incoming virions from endosomes into the cytoplasm, however this remains an intriguing and yet essential process for infection, specifically for the egress of viral nucleic acid into the cytoplasm for replication. ASFV proteins E248R and E199L, located at the exposed inner viral membrane, might be implicated in the fusion step. An interaction between these viral proteins and cellular endosomal proteins such as the Niemann-Pick C type 1 (NPC1) and lysosomal membrane proteins (Lamp-1 and -2) was shown. Furthermore, the silencing of these proteins impaired ASFV infection. It was also observed that NPC1 knock-out cells using CRISPR jeopardized ASFV infection and that the progression and endosomal exit of viral cores was arrested within endosomes at viral entry. These results suggest that the interactions of ASFV proteins with some endosomal proteins might be important for the membrane fusion step. In addition to this, reductions on ASFV infectivity and replication in NPC1 KO cells were accompanied by fewer and smaller viral factories. Our findings pave the way to understanding the role of proteins of the endosomal membrane in ASFV infection., This research was partially supported through the following awards: “La Caixa” Banking Foundation award number LCF/PR/HR19/52160012, Spain, https://fundacionlacaixa.org/en/ to CA and RD, Spanish Ministry of Science and Innovation, Spain RTI2018-097305-R- I00, https://www.ciencia.gob.es/ to CA, Instituto de Investigación Carlos III, ISCIII, Spain FIS PI 1801007, https://www.isciii.es/ to RD, European Commission, Horizon 2020 Framework Programme European Union ASFVInt ERANET-2021-862605 to CA, co-funded by Spanish Ministry of Science and Innovation, Spain PCI2021-121939 https://www.ciencia.gob.es/ to CA, VIRUSCAN FETPROACT-2016- 731868 and EPIC-CROWN-2-2021-101046084 https://ec.europa.eu/ to RD.