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bioRxiv · 10.1101/2022.06.01.494336

PPIX-binding Proteins Reveal Porphyrin Synthesis and Ferroptosis Link

Lynch, J.·Wang, Y.·Li, Y.·Kavidia, K.·Fukuda, Y.·Ranjit, S.·Robinson, C. G.·Grace, C. R.·Xia, Y.·Peng, J.·Schuetz, J.
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Abstract

All aerobic organisms require the cofactor heme to survive, but its synthesis requires formation of a potentially toxic intermediate protoporphyrin IX (PPIX). Little is known about the extent of PPIXs cellular interactions. Here, we report the development of PPB, a biotin-conjugated, PPIX-probe that captures proteins capable of interacting with PPIX. Quantitative proteomics with PPB identified common proteins among a diverse panel of mammalian cell lineages. Pathway and quantitative difference analysis revealed PPB-bound proteins related to iron and heme metabolism and suggested that these processes might be altered by heme/porphyrin synthesis. We show that increased heme/porphyrin synthesis in cells promotes ferroptosis that is pharmacologically distinct from canonical ferroptosis driven by erastin, an inhibitor of the cystine/glutamate antiporter. Proteomic data derived from PPB revealed an interactor, PRDX3, a mitochondrial peroxidase, that modulated heme/porphyrin biosynthesis driven ferroptosis. Consistent with a role in porphyrin-induced ferroptotic death targeted gene knockdown of PRDX3, but not peroxidases, PRDX1 or 2, enhanced porphyrin-induced ferroptotic death. The relationship between increased heme/porphyrin synthesis and ferroptosis was also found in a ferrochelatase-deficient T-lymphoblastoid leukemia cell line, suggesting potential strategy for treating certain cancers. We demonstrate that when the PPB probe is coupled with unbiased proteomics a previously unreported relationship between heme/porphyrin synthesis, and ferroptosis was discovered.

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Lynch, J., Wang, Y., Li, Y., Kavidia, K., Fukuda, Y., Ranjit, S., Robinson, C. G., Grace, C. R., Xia, Y., Peng, J., Schuetz, J.. 2022-06-01. PPIX-binding Proteins Reveal Porphyrin Synthesis and Ferroptosis Link. https://doi.org/10.1101/2022.06.01.494336

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