Flexible linkers in CaMKII control the balance between activating and inhibitory autophosphorylation
Abstract
The many variants of human Ca2+/calmodulin-dependent protein kinase II (CaMKII) differ in the lengths and sequences of disordered linkers connecting the kinase domains to the oligomeric hub of the holoenzyme. CaMKII activity depends on the balance between activating and inhibitory autophosphorylation (on Thr 286 and Thr 305/306, respectively, in the human a isoform). Variation in the linkers could alter transphosphorylation rates within a holoenzyme and the balance of autophosphorylation outcomes. We show, using mammalian-cell expression and a single-molecule assay, that the balance of autophosphorylation is flipped between CaMKII variants with longer and shorter linkers. For the principal isoforms in the brain, CaMKII-a, with a ~30 residue linker, readily acquires activating autophosphorylation, while CaMKII-b, with a ~200 residue linker, is biased towards inhibitory autophosphorylation. Our results show how the responsiveness of CaMKII holoenzymes to calcium signals can be tuned by varying the relative levels of isoforms with long and short linkers.
Data availability
All data generated or analyzed during this study are summarized in the manuscript, figures, appendix, and supplementary files. The in-house Matlab programs that are used for data analysis are provided as Source code file 1 and is open-access.
Article and author information
Author details
Funding
National Institute of General Medical Sciences (K99 GM 126145)
- Moitrayee Bhattacharyya
Howard Hughes Medical Institute
- John Kuriyan
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Tony Hunter, Salk Institute for Biological Studies, United States
Version history
- Received: November 15, 2019
- Accepted: March 6, 2020
- Accepted Manuscript published: March 9, 2020 (version 1)
- Version of Record published: April 8, 2020 (version 2)
Copyright
© 2020, Bhattacharyya 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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