Viruses concentrate

Many reproducing viruses need to concentrate all of their components in one area of the cell, called a viral factory, so that all of their parts are present in sufficient quantities to allow assembly. Now researchers have found that the factories are assembled by cellular machinery that was originally designed to gather together unfolded proteins into a kind of cellular garbage dump.

Thomas Wileman (Institute for Animal Health, Surrey, England) and colleagues report in the April 30 issue of The Journal of Cell Biology that viral factories and the garbage dumps, called aggresomes, share a number of properties. Both are surrounded by a cage of a filamentous protein called vimentin, and both form near a structure in the cell called the microtubule-organizing center (MTOC). Cellular train tracks called microtubules are required for both the establishment and maintenance of the two structures. The cores of the viruses are similar in size to the balls of unfolded proteins that are collected by the aggresome-forming machinery, although the virus must also have a mechanism for breaking apart its vimentin cage so that completed viral particles can be released. Wileman and colleagues are now interested in how this cycle of assembly and disassembly is controlled.

Contact: Thomas Wileman, Institute for Animal Health, Surrey, England, 44-1483232441, [email protected]