Dissecting the neuroprotective interaction between the BH4 domain of BCL-w and the IP3 receptor.

BCL-w is a BCL-2 family protein that promotes cell survival in tissue- and disease-specific contexts. The canonical anti-apoptotic functionality of BCL-w is mediated by a surface groove that traps the BCL-2 homology 3 (BH3) α-helices of pro-apoptotic members, blocking cell death. A distinct N-terminal portion of BCL-w, termed the BCL-2 homology 4 (BH4) domain, selectively protects axons from paclitaxel-induced degeneration by modulating IP3 receptors, a noncanonical BCL-2 family target. Given the potential of BCL-w BH4 mimetics to prevent or mitigate chemotherapy-induced peripheral neuropathy, we sought to characterize the interaction between BCL-w BH4 and the IP3 receptor, combining "staple" and alanine scanning approaches with molecular dynamics simulations. We generated and identified stapled BCL-w BH4 peptides with optimized IP3 receptor binding and neuroprotective activities. Point mutagenesis further revealed the sequence determinants for BCL-w BH4 specificity, providing a blueprint for therapeutic targeting of IP3 receptors to achieve neuroprotection. [Display omitted] • Hydrocarbon staple scanning yielded optimal BCL-w BH4 domain binders of IP3R1 • Molecular dynamics simulations identified a BH4-binding site in ARM2 of IP3R1 • Point mutagenesis revealed the binding determinants for BH4 interaction • A lead stapled BCL-w BH4 peptide protects axons from chemo-induced degeneration Tang et al. report that staple and alanine scanning of the BCL-w BH4 domain revealed binding determinants for targeting IP3R1 by interaction with a surface groove on ARM2, as predicted by molecule dynamics simulations. A lead construct protected axons from paclitaxel-induced degeneration, with point mutagenesis impairing IP3R1 interaction and neuroprotection. [ABSTRACT FROM AUTHOR]