Predicting the Impact of Deleterious Single-Nucleotide Polymorphisms in the p47ING1a Isoform of Human ING1 Gene.

Abstract

The p47ING1a isoform of the ING1 tumor suppressor regulates cellular senescence through Rb-dependent pathways via its plant homeodomain (PHD) zinc-finger, which recognizes the H3K4me3 histone mark. However, the mutational landscape of p47ING1a and the functional consequences of PHD-domain nonsynonymous single-nucleotide polymorphisms (nsSNPs) remain poorly characterized. This study aimed to identify and structurally evaluate the most deleterious nsSNPs in p47ING1a and clarify their potential role in disrupting ING1 tumor-suppressor activity. A total of 347 missense nsSNPs were retrieved from the NCBI dbSNP database and screened using 12 sequence-based computational tools. Variants consistently predicted as deleterious were further evaluated by I-Mutant stability analysis and ConSurf evolutionary conservation profiling. Three-dimensional structural modeling was performed using AlphaFold3, refined through GalaxyRefine, and validated by ERRAT, PROCHECK, and TM-align. Mutation-induced structural and binding effects were assessed using Missense3D, mCSM, and BeAtMuSiC. Post-translational modification sites were predicted via NetPhos 3.1, GPS 3.0, BDM-PUB, and NetOGlyc 4.0. Protein-protein interaction networks were constructed using STRING and Gene MANIA. Pan-cancer expression was analyzed through UALCAN and the Human Protein Atlas. Twelve computational tools converged on six high-priority variants, namely, C358S, C374G, W378G, F379V, S382L, and R400P. All localized exclusively within the PHD zinc-finger domain, residues 353-402. All six mutations were consistently predicted to destabilize the p47ING1a protein across multiple stability analyses. Six nsSNPs in the PHD domain of p47ING1a are predicted to disrupt protein stability, H3K4me3 binding, and Sin3A/HDAC complex interactions, thereby impairing ING1 tumor-suppressor function. These findings provide a computational basis for prioritizing variants for experimental validation through site-directed mutagenesis, chromatin-binding assays, and structure-guided therapeutic targeting of the PHD-H3K4me3 interface.