PMID: 27287556

Authors:

Haywood N, Wolny M, Rogers B, Trinh CH, Shuping Y, Edwards TA, Peckham M

Title:

Hypertrophic Cardiomyopathy Mutations in the calponin-homology domain of ACTN2 affect actin binding and cardiomyocyte Z-disc incorporation.

Journal:

Biochem J. 2016 Jun 10. pii: BCJ20160421.

Abstract:

alpha-actinin 2 (ACTN2) is the only muscle isoform of alpha-actinin expressed in cardiac muscle. Mutations in this protein have been implicated in mild to moderate forms of hypertrophic cardiomyopathy (HCM). We have investigated the effects of two mutations identified from HCM patients; A119T and G111V, on the secondary and tertiary structure of a purified actin binding domain of ACTN2 by circular dichroism and X-ray crystallography, and show small but distinct changes for both mutations. We also find that both mutants have reduced F-actin binding affinity, although the differences are not significant. The full length mEos2 tagged protein expressed in adult cardiomyocytes shows that both mutations additionally affect Z-disc localisation and dynamic behaviour. Overall, these two mutations have small effects on structure, function and behaviour, which may contribute to a mild phenotype for this disease.