Finding. Raptinal has been the compound you add when you want mitochondria to open now. Sun, Hartl, Hornung and colleagues say it does not stab the membrane. It stops new proteins from folding. The proteotoxic wave goes through mitochondrial import, the outer membrane permeabilizes, and apoptosis follows without BAX and BAK. VBIT4 blocks this route. A photoaffinity cousin paints TIM23. Shut the TIM23-PAM axis and this permeabilization dies, while ordinary BAX-BAK apoptosis still runs.
Why this paper matters
Proteostasis people knew unfolded proteins are bad. Mitochondrial-apoptosis people knew MOMP is BAX/BAK. This paper puts import in the middle. It also rewrites two reagents. Raptinal is a folding stressor. VBIT4 is not only a VDAC story.
Score 92. Mechanism, genetics, chemical proteomics, a clean split from BAX/BAK. Confidence is high in the cell systems described.
What to do with it If you use Raptinal, add a folding-and-import control. If you use VBIT4, consider TIM23. Pull the TIM23-PAM rescue versus BAX/BAK panel.