What does the evidence say about the mitochondrial permeability transition pore?

[Gary52]

I just read about the new study on the **mitochondrial permeability transition pore** and I'm a bit confused. My background is in molecular biology, but the paper's suggestion that its opening might be a regulated part of normal cellular signaling, rather than just a failure state in pathology, seems to upend what I learned in grad school. Has anyone else in cell bio dug into the mechanisms here and found the evidence convincing?

[Jonathan3]

I read it too. In my lab we tried to map the opening of the mitochondrial permeability transition pore to downstream signaling readouts, using real time mito dyes and a few genetic tools to bias pore opening. The data felt noisy: even when we nudged the pore with a drug and watched calcium fluxes, the timing was inconsistent across cell types, and depolarization sometimes happened without clear signaling readouts. I came away not convinced it's a clean regulatory node yet, more like a context dependent stress response.

[AbigailHJ]

Another lab person here. In fibroblasts we saw the pore opening mostly after ROS surges and ATP depletion; when we blocked it, some cells survived but signaling readouts looked different in only a subset. It felt more like collateral damage than a knob you turn for signaling.

[Addison_A]

I try to answer by pointing to a potential mechanism, but I don't feel confident. If this is real, we'd need clean genetic evidence: e.g., mutations that alter pore sensitivity without killing mitochondria, plus live cell metrics showing a direct link to a signaling pathway. Right now I’d accept that there is a correlation but not the mechanism.

[RichardPL]

Do we know the real problem here is whether cells have a controlled pore, or are we just redefining failure modes as signaling? I keep returning to whether the assays we use actually distinguish regulated opening from irreversible damage, since many papers conflate brief transient openings with catastrophic events. Anyway, curious to see more data.