Semisynthesis reveals Apoptin as a tumour-selective protein prodrug that causes cytoskeletal collapse

Wyatt, J.; Tavassoli, M.; Mueller, M. M.

doi:10.1101/2022.11.23.517692

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bioRxiv · 10.1101/2022.11.23.517692

Semisynthesis reveals Apoptin as a tumour-selective protein prodrug that causes cytoskeletal collapse

Wyatt, J.·Tavassoli, M.·Mueller, M. M.

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Abstract

Apoptin is a small viral protein capable of inducing cell death selectively in cancer cells. Despite its potential as an anticancer agent, relatively little is known about its mechanism of toxicity and cancer-selectivity. Previous experiments suggest that cancer-selective phosphorylation modulates Apoptin toxicity, although a lack of chemical tools has hampered the dissection of underlying mechanisms. Here, we describe structure-function studies with site-specifically phosphorylated Apoptin (Apoptin-T108ph) in living cells which revealed that Thr108 phosphorylation is the selectivity switch for Apoptin toxicity. Mechanistic investigations link T108ph to actin binding, cytoskeletal disruption and downstream inhibition of anoikis-resistance as well as cancer cell invasion. These results establish Apoptin as a protein pro-drug, selectively activated in cancer cells by phosphorylation, which disrupts the cytoskeleton and promotes cell death. We anticipate that this mechanism provides a framework for the design of next generation anticancer proteins with enhanced selectivity and potency.

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Wyatt, J., Tavassoli, M., Mueller, M. M.. 2022-11-25. Semisynthesis reveals Apoptin as a tumour-selective protein prodrug that causes cytoskeletal collapse. https://doi.org/10.1101/2022.11.23.517692

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