Conformational regulation and target-myristoyl switch of calcineurin B homologous protein 3
- University of Freiburg, Germany
Abstract
Calcineurin B homologous protein 3 (CHP3) is an EF-hand Ca2+-binding protein involved in regulation of cancerogenesis, cardiac hypertrophy and neuronal development through interactions with sodium/proton exchangers (NHEs) and signalling proteins. While the importance of Ca2+ binding and myristoylation for CHP3 function has been recognized, the underlying molecular mechanism remained elusive. In this study, we demonstrate that Ca2+ binding and myristoylation independently affect the conformation and functions of human CHP3. Ca2+ binding increased local flexibility and hydrophobicity of CHP3 indicative of an open conformation. The Ca2+-bound CHP3 exhibited a higher affinity for NHE1 and associated stronger with lipid membranes compared to the Mg2+-bound CHP3, which adopted a closed conformation. Myristoylation enhanced the local flexibility of CHP3 and decreased its affinity to NHE1 independently of the bound ion, but did not affect its binding to lipid membranes. The data exclude the proposed Ca2+-myristoyl switch for CHP3. Instead, a Ca2+-independent exposure of the myristoyl moiety is induced by binding of the target peptide to CHP3 enhancing its association to lipid membranes. We name this novel regulatory mechanism 'target-myristoyl switch'. Collectively, the interplay of Ca2+ binding, myristoylation, and target binding allows for a context-specific regulation of CHP3 functions.
Data availability
All data generated or analyzed during this study are included in the manuscript. Source files have been provided for Figures 1, 4, 6, and Figure 4-figure supplement 1. Data2Dynamics Software used for EC50 and KD determination is available at GitHub (https://github.com/Data2Dynamics/d2d).
Article and author information
Author details
Funding
Deutsche Forschungsgemeinschaft (EXC-2189 - 390939984)
- Clemens Kreutz
- Bettina Warscheid
- Bernd Fakler
- Evgeny V Mymrikov
- Carola Hunte
Deutsche Forschungsgemeinschaft (SFB 1381 - 403222702)
- Uwe Schulte
- Bettina Warscheid
- Carola Hunte
Deutsche Forschungsgemeinschaft (SFB 1453 - 431984000)
- Bernd Fakler
- Carola Hunte
Deutsche Forschungsgemeinschaft (RTG 2202 - 278002225)
- Carola Hunte
Bundesministerium für Bildung und Forschung (FKZ031L0080)
- Clemens Kreutz
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2023, Becker et al.
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.
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Conformational regulation and target-myristoyl switch of calcineurin B homologous protein 3
eLife 12:e83868.
https://doi.org/10.7554/eLife.83868
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