Functional cross-talk between phosphorylation and disease-causing mutations in the cardiac sodium channel Nav1.5
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Functional cross-talk between phosphorylation and disease-causing mutations in the cardiac sodium channel Nav1.5. / Galleano, Iacopo; Harms, Hendrik; Choudhury, Koushik; Khoo, Keith; Delemotte, Lucie; Pless, Stephan Alexander.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 118, No. 33, e2025320118, 2021.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Functional cross-talk between phosphorylation and disease-causing mutations in the cardiac sodium channel Nav1.5
AU - Galleano, Iacopo
AU - Harms, Hendrik
AU - Choudhury, Koushik
AU - Khoo, Keith
AU - Delemotte, Lucie
AU - Pless, Stephan Alexander
N1 - Publisher Copyright: © 2021 National Academy of Sciences. All rights reserved.
PY - 2021
Y1 - 2021
N2 - The voltage-gated sodium channel Nav1.5 initiates the cardiac action potential. Alterations of its activation and inactivation properties due to mutations can cause severe, life-threatening arrhythmias. Yet despite intensive research efforts, many functional aspects of this cardiac channel remain poorly understood. For instance, Nav1.5 undergoes extensive posttranslational modification in vivo, but the functional significance of these modifications is largely unexplored, especially under pathological conditions. This is because most conventional approaches are unable to insert metabolically stable posttranslational modification mimics, thus preventing a precise elucidation of the contribution by these modifications to channel function. Here, we overcome this limitation by using protein semisynthesis of Nav1.5 in live cells and carry out complementary molecular dynamics simulations. We introduce metabolically stable phosphorylation mimics on both wild-type (WT) and two pathogenic long-QT mutant channel backgrounds and decipher functional and pharmacological effects with unique precision. We elucidate the mechanism by which phosphorylation of Y1495 impairs steady-state inactivation in WT Nav1.5. Surprisingly, we find that while the Q1476R patient mutation does not affect inactivation on its own, it enhances the impairment of steady-state inactivation caused by phosphorylation of Y1495 through enhanced unbinding of the inactivation particle. We also show that both phosphorylation and patient mutations can impact Nav1.5 sensitivity toward the clinically used antiarrhythmic drugs quinidine and ranolazine, but not flecainide. The data highlight that functional effects of Nav1.5 phosphorylation can be dramatically amplified by patient mutations. Our work is thus likely to have implications for the interpretation of mutational phenotypes and the design of future drug regimens.
AB - The voltage-gated sodium channel Nav1.5 initiates the cardiac action potential. Alterations of its activation and inactivation properties due to mutations can cause severe, life-threatening arrhythmias. Yet despite intensive research efforts, many functional aspects of this cardiac channel remain poorly understood. For instance, Nav1.5 undergoes extensive posttranslational modification in vivo, but the functional significance of these modifications is largely unexplored, especially under pathological conditions. This is because most conventional approaches are unable to insert metabolically stable posttranslational modification mimics, thus preventing a precise elucidation of the contribution by these modifications to channel function. Here, we overcome this limitation by using protein semisynthesis of Nav1.5 in live cells and carry out complementary molecular dynamics simulations. We introduce metabolically stable phosphorylation mimics on both wild-type (WT) and two pathogenic long-QT mutant channel backgrounds and decipher functional and pharmacological effects with unique precision. We elucidate the mechanism by which phosphorylation of Y1495 impairs steady-state inactivation in WT Nav1.5. Surprisingly, we find that while the Q1476R patient mutation does not affect inactivation on its own, it enhances the impairment of steady-state inactivation caused by phosphorylation of Y1495 through enhanced unbinding of the inactivation particle. We also show that both phosphorylation and patient mutations can impact Nav1.5 sensitivity toward the clinically used antiarrhythmic drugs quinidine and ranolazine, but not flecainide. The data highlight that functional effects of Nav1.5 phosphorylation can be dramatically amplified by patient mutations. Our work is thus likely to have implications for the interpretation of mutational phenotypes and the design of future drug regimens.
KW - Cardiac arrhythmia
KW - Personalized medicine
KW - Pharmacology
KW - Protein engineering
KW - Sodium channel inactivation
U2 - 10.1073/pnas.2025320118
DO - 10.1073/pnas.2025320118
M3 - Journal article
C2 - 34373326
AN - SCOPUS:85112333130
VL - 118
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 33
M1 - e2025320118
ER -
ID: 283214865