In the nematode worm Caenorhabditis elegans, as in humans, offspring inherit mitochondria and mitochondrial DNA only from their mother. Sato et al. identified key molecular components of the machinery that recognizes male mitochondria and targets them for degradation. In a screen for kinases that might be required for the process, they identified IKKE-1, a protein kinase with similarity to the mammalian protein kinases TBK1 and IKBKE. IKKE-1 interacted with a protein that they named ALLO-1, which had sequence similarity to autophagy receptors and was required for clearance of paternal organelles. The similarity of the role of IKKE-1 in removing male mitochondria to that of mammalian TBK1, which functions in the innate immune response, hints that the two processes might have a similar evolutionary origin.
