Sat, 26 Jul 2008 07:23:42 BST CiteULike: lechristophe's Helenius http://www.citeulike.org/user/lechristophe/author/Helenius CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/lechristophe/article/2718925 <i>Science, Vol. 320, No. 5875. (25 April 2008), pp. 531-535.</i><br /><br />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. 10.1126/science.1155164 Vaccinia Virus Uses Macropinocytosis and Apoptotic Mimicry to Enter Host Cells Jason Mercer Ari Helenius doi:10.1126/science.1155164 Science, Vol. 320, No. 5875. (25 April 2008), pp. 531-535. 2008-04-25T16:18:21-00:00 2008 Science 320 5875 531 535 cell_culture endocytosis virus_entry http://www.citeulike.org/user/lechristophe/article/1540589 <i>PLoS Biol, Vol. 3, No. 7. (July 2005)</i><br /><br />Semliki forest virus (SFV) is internalized by clathrin-mediated endocytosis, and transported via early endosomes to late endosomes and lysosomes. The intracellular pathway taken by individual fluorescently labeled SFV particles was followed using immunofluorescence in untransfected cells, and by video-enhanced, triple-color fluorescence microscopy in live cells transfected with GFP- and RFP-tagged Rab5, Rab7, Rab4, and Arf1. The viruses progressed from Rab5-positive early endosomes to a population of early endosomes (about 10% of total) that contained both Rab5 and Rab7. SFV were sequestered in the Rab7 domains, and they were sorted away from the early endosomes when these domains detached as separate transport carriers devoid of Rab5, Rab4, EEA1, Arf1, and transferrin. The process was independent of Arf1 and the acidic pH in early endosomes. Nocodazole treatment showed that the release of transport carriers was assisted by microtubules. Expression of constitutively inactive Rab7T22N resulted in accumulation of SFV in early endosomes. We concluded that Rab7 is recruited to early endosomes, where it forms distinct domains that mediate cargo sorting as well as the formation of late-endosome-targeted transport vesicles. Rab7 associates with early endosomes to mediate sorting and transport of Semliki forest virus to late endosomes. A Vonderheit A Helenius doi:10.1371/journal.pbio.0030233 PLoS Biol, Vol. 3, No. 7. (July 2005) 2007-08-07T13:15:30-00:00 2005 PLoS Biol 1545-7885 3 7 endocytosis endosomes fluorescent_proteins intracellular live_cell_imaging rab trafficking