BioID based proteomic screen identifies VDAC2 as a coordinator of Bid dependent apoptotic priming during mitosis.

Apoptotic priming refers to the proximity of cells to outer mitochondrial membrane permeabilisation (MOMP), the point of apoptosis commitment. Variations in priming are important for how both normal and cancer cells respond to chemotherapeutic agents. Individual cells adjust their level of priming in response to changing circumstances, such as genomic damage. How changes in apoptotic priming are dynamically coordinated by Bcl-2 proteins remains unclear. We have previously demonstrated that the Bcl-2 protein, Bid, becomes phosphorylated as cell enter mitosis, increasing priming. To understand how cells coordinate dynamic changes in priming, we have performed an unbiased proximity biotinylation (BioID) screen using Bid as bait. This identified several potential regulatory proteins outside the core Bcl-2 family. In particular we found VDAC2 to be essential for Bid phosphorylation dependent changes in apoptotic priming during mitosis. These results show the importance of dissecting the wider Bcl-2 interactome, and identify a key scaffold protein coordinating dynamic changes in single cell priming.