Allosteric regulators selectively prevent Ca2+-feedback of CaV and NaV channels

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Abstract

Calmodulin (CaM) serves as a pervasive regulatory subunit of Ca_V1, Ca_V2, and Na_V1 channels, exploiting a functionally-conserved carboxy-tail element to afford dynamic Ca²⁺-feedback of cellular excitability in neurons and cardiomyocytes. Yet this modularity counters functional adaptability, as global changes in ambient CaM indiscriminately alter its targets. Here, we demonstrate that two structurally-unrelated proteins, SH3 and cysteine-rich domain (stac) and fibroblast growth factor homologous factors (fhf) selectively diminish Ca²⁺/CaM-regulation of Ca_V1 and Na_V1 families respectively. The two proteins operate on allosteric sites within upstream portions of respective channel carboxy-tails, distinct from CaM-binding interface. Generalizing this mechanism, insertion of a short RxxK binding motif into Ca_V1.3 carboxy-tail, confers synthetic switching of CaM regulation by Mona SH3 domain. Overall, our findings identify a general class of auxiliary proteins that modify Ca²⁺/CaM signaling to individual targets allowing spatial and temporal orchestration of feedback, and outline strategies for engineering Ca²⁺/CaM signaling to individual targets.

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All data generated or analysed during this study are included in the manuscript and supporting files.

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Jacqueline Niu

Department of Biomedical Engineering, Johns Hopkins University, Baltimore, United States

Competing interests
The authors declare that no competing interests exist.
Ivy E Dick

Department of Physiology, University of Maryland, Baltimore, United States

Competing interests
The authors declare that no competing interests exist.
Wanjun Yang

Department of Cardiology, Johns Hopkins University, Baltimore, United States

Competing interests
The authors declare that no competing interests exist.
Moradeke A Bamgboye

Department of Physiology, University of Maryland, Baltimore, United States

Competing interests
The authors declare that no competing interests exist.
David T Yue

Department of Biomedical Engineering, Johns Hopkins University, Baltimore, United States

Competing interests
The authors declare that no competing interests exist.
Gordon Tomaselli

Department of Cardiology, Johns Hopkins University, Baltimore, United States

Competing interests
The authors declare that no competing interests exist.
Takanari Inoue

Department of Cell Biology, Johns Hopkins University, Baltimore, United States

For correspondence
jctinoue@jhmi.edu

Competing interests
The authors declare that no competing interests exist.
Manu Ben-Johny

Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, United States

For correspondence
mbj2124@cumc.columbia.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-5645-0815

Funding

National Institute of Mental Health

David T Yue
Manu Ben-Johny

National Heart, Lung, and Blood Institute

Gordon Tomaselli
Manu Ben-Johny

National Science Foundation

Jacqueline Niu

National Institute of Neurological Disorders and Stroke

Ivy E Dick
David T Yue

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols of the Johns Hopkins University (GP15M172). The protocol was approved by the Committee on the Ethics of Animal Experiments of the Johns Hopkins University. All surgery was performed under sodium pentobarbital anesthesia, and every effort was made to minimize suffering.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.