title: Vaccinia virus uses macropinocytosis and apoptotic mimicry to enter host cells.
abstract: Viruses employ many different strategies to enter host cells. Vaccinia virus, a prototype poxvirus, enters cells in a pH-dependent fashion. Live cell imaging showed that fluorescent virus particles associated with and moved along filopodia to the cell body, where they were internalized after inducing the extrusion of large transient membrane blebs. p21-activated kinase 1 (PAK1) was activated by the virus, and the endocytic process had the general characteristics of macropinocytosis. The induction of blebs, the endocytic event, and infection were all critically dependent on the presence of exposed phosphatidylserine in the viral membrane, which suggests that vaccinia virus uses apoptotic mimicry to enter cells.
authors.affiliation: ETH Zurich, Institute of Biochemistry, Schafmattstrasse 18, ETH Hönggerberg HPM E6.3 Zurich, Switzerland.
authors.forename: Jason
authors.initials: J
authors.lastname: Mercer
authors.forename: Ari
authors.initials: A
authors.lastname: Helenius
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D010718:Phosphatidylserines / Q000378:metabolism*; D010873:Pinocytosis; D034622:RNA Interference; D014616:Vaccinia virus / Q000502:physiology*; D053586:Virus Internalization; D054462:p21-Activated Kinases / Q000235:genetics / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D000199:Actins; D010718:Phosphatidylserines; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein