File:Baculovirus actin comet 01.mp4

Live cell imaging of baculovirus actin comets. (Part 1) Actin comet tails in mCherry-baculovirus-infected B16 melanoma cells transfected with GFP actin. (Part 2) Examples of baculovirus-induced actin comet tails in B16 cells transfected with the indicated proteins, as used for kymograph analysis (see Figures 1B and S1). Heads of comet tails are marked by red arrows. doi:10.1371/journal.pbio.1001765.s008

PLoS Biol. 2014 Jan;12(1):e1001765. doi: 10.1371/journal.pbio.1001765. Epub 2014 Jan 14. Electron tomography and simulation of baculovirus actin comet tails support a tethered filament model of pathogen propulsion. Mueller J1, Pfanzelter J1, Winkler C2, Narita A3, Le Clainche C4, Nemethova M1, Carlier MF4, Maeda Y5, Welch MD6, Ohkawa T6, Schmeiser C2, Resch GP7, Small JV1. Author information Abstract Several pathogens induce propulsive actin comet tails in cells they invade to disseminate their infection. They achieve this by recruiting factors for actin nucleation, the Arp2/3 complex, and polymerization regulators from the host cytoplasm. Owing to limited information on the structural organization of actin comets and in particular the spatial arrangement of filaments engaged in propulsion, the underlying mechanism of pathogen movement is currently speculative and controversial. Using electron tomography we have resolved the three-dimensional architecture of actin comet tails propelling baculovirus, the smallest pathogen yet known to hijack the actin motile machinery. Comet tail geometry was also mimicked in mixtures of virus capsids with purified actin and a minimal inventory of actin regulators. We demonstrate that propulsion is based on the assembly of a fishbone-like array of actin filaments organized in subsets linked by branch junctions, with an average of four filaments pushing the virus at any one time. Using an energy-minimizing function we have simulated the structure of actin comet tails as well as the tracks adopted by baculovirus in infected cells in vivo. The results from the simulations rule out gel squeezing models of propulsion and support those in which actin filaments are continuously tethered during branch nucleation and polymerization. Since Listeria monocytogenes, Shigella flexneri, and Vaccinia virus among other pathogens use the same common toolbox of components as baculovirus to move, we suggest they share the same principles of actin organization and mode of propulsion. Comment in Actin comets: traversing the cellular universe. [PLoS Biol. 2014]

PMID 24453943

http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1001765

Copyright: © 2014 Mueller et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.