BK polyomavirus evades innate immune sensing by disrupting the mitochondrial network and membrane potential and promotes mitophagy
Immune escape contributes to viral persistence, yet little is known about human polyomaviruses. BK-polyomavirus (BKPyV) asymptomatically infects 90% of the human population, but causes early allograft failure in 10% of kidney transplants. Despite inducing potent virus-specific T-cells and neutralizing antibodies, BKPyV persists in the kidneys and regularly escapes from immune control as indicated by urinary shedding in immunocompetent individuals. Here, we report that BKPyV disrupts the mitochondrial network and its membrane potential when expressing the 66aa-long agnoprotein during late replication. Agnoprotein impairs nuclear IRF3-translocation, interferon-{beta} expression, and promotes p62-mitophagy in vitro and in kidney transplant biopsies. Agnoprotein-mutant viruses unable to disrupt mitochondria show reduced replication, which can be rescued by type-I-interferon-blockade, TBK1-inhibition, or CoCl2 treatment. Agnoprotein is necessary and sufficient, using its amino-terminal and central domain for mitochondrial targeting and disruption, respectively. JCPyV- and SV40-infection similarly disrupt the mitochondrial network indicating a conserved mechanism facilitating polyomavirus persistence and post-transplant disease.