title: African horse sickness virus infects BSR cells through macropinocytosis.
abstract: Cellular pathways involved in cell entry by African horse sickness virus (AHSV), a member of the Orbivirus genus within the Reoviridae family, have not yet been determined. Here, we show that acidic pH is required for productive infection of BSR cells by AHSV-4, suggesting that the virus is likely internalized by an endocytic pathway. We subsequently analyzed the major endocytic routes using specific inhibitors and determined the consequences for AHSV-4 entry into BSR cells. The results indicated that virus entry is dynamin dependent, but clathrin- and lipid raft/caveolae-mediated endocytic pathways were not used by AHSV-4 to enter and infect BSR cells. Instead, binding of AHSV-4 to BSR cells stimulated uptake of a macropinocytosis-specific cargo and inhibition of Na(+)/H(+) exchangers, actin polymerization and cellular GTPases and kinases involved in macropinocytosis significantly inhibited AHSV-4 infection. Altogether, the data suggest that AHSV-4 infects BSR cells by utilizing macropinocytosis as the primary entry pathway.
authors: Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa.
authors: Elaine
authors: E
authors: Vermaak
authors: Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa.
authors: Andelé M
authors: AM
authors: Conradie
authors: Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa; Transboundary Animal Diseases, Onderstepoort Veterinary Institute, Agricultural Research Council, Pretoria 0110, South Africa.
authors: Francois F
authors: FF
authors: Maree
authors: Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa. Electronic address: jacques.theron@up.ac.za.
authors: Jacques
authors: J
authors: Theron
mesh_terms: D000199:Actins / Q000378:metabolism; D000355:African Horse Sickness / Q000821:virology*; D000356:African Horse Sickness Virus / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D002460:Cell Line; D002784:Cholesterol; D006224:Cricetinae; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism / Q000821:virology; D006863:Hydrogen-Ion Concentration; D053586:Virus Internalization
chemical_list: D000199:Actins; D002784:Cholesterol; D034281:Dynamins
keywords: African horse sickness virus; Cell entry; Endocytosis; Macropinocytosis; Orbivirus