The rubella virus capsid protein inhibits mitochondrial import.
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.
Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
Carolina S
CS
Ilkow
Daniel
D
Weckbecker
Woo Jung
WJ
Cho
Stephan
S
Meier
Martin D
MD
Beatch
Ing Swie
IS
Goping
Johannes M
JM
Herrmann
Tom C
TC
Hobman
D000818:Animals; D036022:Capsid Proteins / Q000235:genetics / Q000502:physiology*; D002522:Chlorocebus aethiops; D008928:Mitochondria / Q000378:metabolism / Q000821:virology*; D024101:Mitochondrial Proteins / Q000037:antagonists & inhibitors*; D016297:Mutagenesis, Site-Directed; D021381:Protein Transport; D012412:Rubella virus / Q000737:chemistry*; D014709:Vero Cells; D014764:Viral Proteins; D015003:Yeasts
D036022:Capsid Proteins; D024101:Mitochondrial Proteins; D014764:Viral Proteins