Prakash, Ohm, Gupta, Nitika 
ORCID: 0000-0003-3885-2500, Milburn, Amy, McCormick, Liam, Deugi, Vishvangi, Fisch, Pauline, Wyles, Jacob, Thomas, N Lowri, Antonyuk, Svetlana ORCID: 0000-0002-2779-9946, Dart, Caroline ORCID: 0000-0002-3509-8349 et al (show 1 more authors)
(2023)
Calmodulin variant E140G associated with long QT syndrome impairs CaMKIIδ autophosphorylation and L-type calcium channel inactivation.
JOURNAL OF BIOLOGICAL CHEMISTRY, 299 (1).
102777-.
Abstract
Long QT syndrome (LQTS) is a human inherited heart condition that can cause life-threatening arrhythmia including sudden cardiac death. Mutations in the ubiquitous Ca<sup>2+</sup>-sensing protein calmodulin (CaM) are associated with LQTS, but the molecular mechanism by which these mutations lead to irregular heartbeats is not fully understood. Here, we use a multidisciplinary approach including protein biophysics, structural biology, confocal imaging, and patch-clamp electrophysiology to determine the effect of the disease-associated CaM mutation E140G on CaM structure and function. We present novel data showing that mutant-regulated CaMKIIδ kinase activity is impaired with a significant reduction in enzyme autophosphorylation rate. We report the first high-resolution crystal structure of a LQTS-associated CaM variant in complex with the CaMKIIδ peptide, which shows significant structural differences, compared to the WT complex. Furthermore, we demonstrate that the E140G mutation significantly disrupted Ca<sub>v</sub>1.2 Ca<sup>2+</sup>/CaM-dependent inactivation, while cardiac ryanodine receptor (RyR2) activity remained unaffected. In addition, we show that the LQTS-associated mutation alters CaM's Ca<sup>2+</sup>-binding characteristics, secondary structure content, and interaction with key partners involved in excitation-contraction coupling (CaMKIIδ, Ca<sub>v</sub>1.2, RyR2). In conclusion, LQTS-associated CaM mutation E140G severely impacts the structure-function relationship of CaM and its regulation of CaMKIIδ and Ca<sub>v</sub>1.2. This provides a crucial insight into the molecular factors contributing to CaM-mediated arrhythmias with a central role for CaMKIIδ.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Myocytes, Cardiac, Humans, Long QT Syndrome, Calcium, Calmodulin, Calcium Channels, L-Type, Ryanodine Receptor Calcium Release Channel, Crystallography, Protein Structure, Secondary, Protein Binding, Mutation, Arrhythmias, Cardiac, Calcium-Calmodulin-Dependent Protein Kinase Type 2 |
| Divisions: | Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Life Courses and Medical Sciences Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 19 Jan 2023 09:53 |
| Last Modified: | 18 Oct 2023 18:19 |
| DOI: | 10.1016/j.jbc.2022.102777 |
| Open Access URL: | https://doi.org/10.1016/j.jbc.2022.102777 |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3167136 |
Dimensions
Dimensions
