Comprehensive biophysical and structural profiling of alpha-actinin-2 variants reveals mechanistic diversity in hypertrophic cardiomyopathy.
M, N., H, M., N, C., N, P., P, R., A, S., C, R., S, L., C, D., & F, M. (2026). Comprehensive biophysical and structural profiling of alpha-actinin-2 variants reveals mechanistic diversity in hypertrophic cardiomyopathy.. Nature communications. https://doi.org/10.1038/s41467-026-75392-z
M N, H M, N C, N P, P R, A S, et al. Comprehensive biophysical and structural profiling of alpha-actinin-2 variants reveals mechanistic diversity in hypertrophic cardiomyopathy.. Nature communications. 2026; doi: 10.1038/s41467-026-75392-z
M N, H M, N C, et al. Comprehensive biophysical and structural profiling of alpha-actinin-2 variants reveals mechanistic diversity in hypertrophic cardiomyopathy.[J]. Nature communications. 2026. DOI: 10.1038/s41467-026-75392-z.
@article{m2026,
author = {Noureddine M and Mikolajek H and Cowieson N and Pinotsis N and Robinson P and Slater A and Redwood C and Loughna S and Denning C and Mohammed F},
title = {Comprehensive biophysical and structural profiling of alpha-actinin-2 variants reveals mechanistic diversity in hypertrophic cardiomyopathy.},
journal = {Nature communications},
year = {2026},
doi = {10.1038/s41467-026-75392-z},
note = {PMID: 42481460},
}
TY - JOUR AU - Noureddine M AU - Mikolajek H AU - Cowieson N AU - Pinotsis N AU - Robinson P AU - Slater A AU - Redwood C AU - Loughna S AU - Denning C AU - Mohammed F TI - Comprehensive biophysical and structural profiling of alpha-actinin-2 variants reveals mechanistic diversity in hypertrophic cardiomyopathy. T2 - Nature communications PY - 2026 DO - 10.1038/s41467-026-75392-z AN - PMID:42481460 ER -
Hypertrophic cardiomyopathy (HCM) is a genetic disease associated with sudden cardiac death. Variants in alpha-actinin-2 (ACTN2), a Z-disc protein that anchors actin thin filaments have been implicated in HCM, yet their structural consequences remain poorly defined. Here, we characterise seventeen HCM-associated ACTN2 variants spanning multiple domains using an integrated and tiered workflow combining high-throughput assays, structural modelling and biophysical approaches. All variants display reduced solubility, with actin-binding domain (ABD) substitutions showing pronounced thermal instability by differential scanning fluorimetry. Modelling of nine variants predicts diverse pathogenic mechanisms including compromised actin-binding, impaired ABD regulatory conformations, disrupted dimerisation interfaces, and perturbed domain architecture. Crystal structures of two rod-domain variants reveal intact dimerisation despite modelling predictions. Actin-binding assays for ABD variants confirm altered actin engagement suggesting that binding dynamics may drive pathogenicity. Limited proteolysis indicates reduced structural stability across variants, while size-exclusion chromatography coupled with multi-angle light scattering or small-angle X-ray scattering (SEC-MALS/SAXS) shows a strong propensity for aggregation. Batch-mode SAXS further demonstrates early aggregation onset in selected ABD variants at elevated temperatures. Collectively, these findings establish that HCM-linked ACTN2 variants compromise protein integrity through multiple mechanisms, highlight the ABD as a hotspot of vulnerability and provide a potential framework for interpreting cardiomyopathy-associated variants.