Summary of scaffold stabilizing interactions and aggregation loci of VDACs. (A) Summary of the stable and aggregation prone variants deduced from this study. The heat maps show the stability (left) and aggregation tendency (right) for most and least stable hV3 mutants. Numbers in the heat map show the data range for each parameter. The C8,122A and C2,36,65,229A mutants are most stable and exhibit least aggregation across the mutants (A, right side in the heat map, green color). The C2,8,122,229A and C2,8A mutants show highest aggregation propensity because of the presence of C36 and C65 pair (right; left side in the heat map, red color). Note that the presence of C36 and C65 does not considerably influence protein stability (see Fig. S2 C). Overall, the results show the importance of C2, C8, and C122 (α1–β7–β9 interaction triad) for the hV3 stability, and involvement of C36 and C65 for hV3 aggregation. (B) Schematic highlighting the α1–β7–β9 interaction triad (surface presentation, green color), dictating stability of the hV3 barrel. When this interaction is disrupted, hV3 is destabilized, and strands β7–β9 now become aggregation prone (shown as red surface presentation). (C) Putative model for VDAC aggregation in the cell. The α1–β7–β9 interaction triad (green triangle; C2, C8, C122 as green spheres) may suppress VDAC aggregation under physiological conditions (top left). During cellular stress, this stabilizing α1–β7–β9 interaction (C2, C8, C122 now shown as red spheres) may be disrupted (top right). Evidence for this destabilization is available for irreversible VDAC oxidation (Reina et al., 2016a) and sequestering of the α1 helix by Aβ (Smilansky et al., 2015). Both the processes can induce VDAC oligomerization (lower panel) at the aggregation hotspots. Progressive VDAC aggregation over a prolonged time may result in cell death and neurodegeneration.