rubella virus capsid protein inhibits mitochondrial import

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The rubella virus capsid protein inhibits mitochondrial import.

<http://www.ncbi.nlm.nih.gov/pubmed/19846524>

Ilkow CS, Weckbecker D, Cho WJ, Meier S, Beatch MD, Goping IS, Herrmann

JM, Hobman TC.

J Virol. 2010 Jan;84(1):119-30. Epub

The rubella virus (RV) capsid is an RNA-binding protein that functions

in nucleocapsid assembly at the Golgi complex, the site of virus

budding. In addition to its role in virus assembly, pools of capsid

associate with mitochondria, a localization that is not consistent with

virus assembly. Here we examined the interaction of capsid with

mitochondria and showed that this viral protein inhibits the import and

processing of mitochondrial precursor proteins in vitro. Moreover,

RV-infected cells were found to contain lower intramitochondrial levels

of matrix protein p32. In addition to inhibiting the translocation of

substrates into mammalian mitochondria, capsid efficiently blocked

import into yeast mitochondria, thereby suggesting that it acts by

targeting a highly conserved component of the translocation apparatus.

Finally, mutation of a cluster of five arginine residues in the amino

terminus of capsid, though not interfering with its binding to

mitochondria, abrogated its ability to block protein import into

mitochondria. This is the first report of a viral protein that affects

the import of proteins into mitochondria.