F. Stavru et al. (2011). PNAS 108:9, 3612-3617
LLO induces mitochondrial fragmentation without affecting total levels of key mitochondrial dynamics proteins.
(A) HeLa cells infected (1 h, MOI of 50) with a noninvasive L. monocytogenes mutant (ΔinlB) display fragmented mitochondria, indicating bacterial entry is not required. In contrast, no fragmentation occurs with
infection by an LLO-deficient mutant (Δhly). Bacteria were stained with anti L. monocytogenes (R11, green), mitochondria were stained with anti-cytochrome c (red), and DNA was stained with DAPI (blue). Insets show 2× enlargements of mitochondria. Arrows point to infected cells. (B) L. monocytogenes carrying a point mutation in the hly gene inactivating its pore-forming ability (W492A) do not cause mitochondrial fragmentation. Mitochondria (red) and bacteria (green) were stained as in A. (C) HeLa cell treatment with recombinant LLO (10 min, 6 nM) was sufficient to induce mitochondrial fragmentation. Mitochondria (red) were stained as in A.