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Myosin Motor Domains Carrying Mutations Implicated in Early or Late Onset Hypertrophic Cardiomyopathy Have Similar Properties

Vera, Carlos D., Johnson, Chloe A, Walklate, Jonathan, Adhikari, Arjun, Svicevic, Marina, Mijailovich, Srbolujub M, Combs, Ariana C., Langer, Stephen J., Ruppel, Kathleen M., Spudich, James A, and others. (2019) Myosin Motor Domains Carrying Mutations Implicated in Early or Late Onset Hypertrophic Cardiomyopathy Have Similar Properties. Journal of Biological Chemistry, 294 . pp. 17451-17462. ISSN 0021-9258. (doi:10.1074/jbc.RA119.010563)

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https://doi.org/10.1074/jbc.RA119.010563

Abstract

Hypertrophic cardiomyopathy (HCM) is a common genetic disorder characterized by left ventricular hypertrophy and cardiac hyper-contractility. Mutations in the β cardiac myosin heavy chain gene (β-MyHC) are a major cause of HCM, but the specific mechanistic changes to myosin function that lead to this disease remain incompletely understood. Predicting the severity of any β-MyHC mutation is hindered by a lack of detailed examinations at the molecular level. Moreover, since HCM can take ≥20 years to develop, the severity of the mutations must be somewhat subtle. We hypothesized that mutations that result in early onset disease would have more severe changes in function than do later onset mutations. Here, we performed steady-state and transient kinetic analyses of myosins carrying one of seven missense mutations in the motor domain. Of these seven, four were previously identified in early onset cardiomyopathy screens. We used the parameters derived from these analyses to model the ATP driven cross-bridge cycle. Contrary to our hypothesis, the results indicated no clear differences between early and late onset HCM mutations. Despite the lack of distinction between early and late onset HCM, the predicted occupancy of the force-holding actin.myosin.ADP complex at [Actin] = 3 Kapp along with the closely related duty ratio (DR; the fraction of myosin in strongly attached force-holding states) and the measured ATPases all changed in parallel (in both sign and degree of change) compared to wild type (WT) values. Six of the seven HCM mutations were clearly distinct from a set of previously characterized DCM mutations.

Item Type: Article
DOI/Identification number: 10.1074/jbc.RA119.010563
Uncontrolled keywords: Hypertrophic cardiomyopathy, Actin-myosin, molecular, motor kinetics, mathematical modeling, cardiomyopathy, structure-function
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Sue Davies
Date Deposited: 08 Oct 2019 08:54 UTC
Last Modified: 25 Nov 2019 13:16 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/77115 (The current URI for this page, for reference purposes)
Geeves, Michael A.: https://orcid.org/0000-0002-9364-8898
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