Unconventional binding of calmodulin to CHK2 kinase inhibits catalytic activity

Christopher R. Horne; Tingting Wang; Samuel N. Young; Toby A. Dite; Hunter G. Nyvall; Sushant Suresh; Katherine A. Davies; Abner Gonzalez Castro; Vineet Vaibhav; Lucy J. Mather; Laura F. Dagley; Matthew J. Belousoff; Gerard Manning; Anthony R. Means; John E. Burke; Janni Petersen; John W. Scott; James M. Murphy

doi:10.1042/BCJ20253431

Unconventional binding of calmodulin to CHK2 kinase inhibits catalytic activity

Christopher R. Horne, Tingting Wang, Samuel N. Young, Toby A. Dite, Hunter G. Nyvall, Sushant Suresh, Katherine A. Davies, Abner Gonzalez Castro, Vineet Vaibhav, Lucy J. Mather, Laura F. Dagley, Matthew J. Belousoff, Gerard Manning, Anthony R. Means, John E. Burke, Janni Petersen, John W. Scott, James M. Murphy

College of Medicine and Public Health

Research output: Contribution to journal › Article › peer-review

1 Downloads (Pure)

Abstract

Calmodulin (CaM) serves an essential role in eukaryotic cells as a Ca2+ sensor. Ca2+ binding leads to conformation changes in CaM that enable engagement of a repertoire of enzymes and the regulation of their catalytic activities. Classically, Ca2+-CaM binds to an inhibitory pseudosubstrate sequence C-terminal to the kinase domain in members of the Ca2+-CaM-dependent protein kinase (CAMK) family and relieves inhibition to promote catalytic activity. Here, we report an unexpected mechanism by which CaM can bind CHK2 kinase to inhibit its kinase activity. Using biochemical, biophysical and structural mass spectrometry, we identify a direct interaction of Ca2+-CaM with the CHK2 kinase domain that suppresses CHK2 catalytic activity in vitro and identify K373 in CHK2 as crucial for cell proliferation in human cells following DNA damage. Our findings add direct suppression of kinase activity to the repertoire of CaM's functions, complementing the paradigmatic mechanism of promoting kinase activity through autoinhibitory domain sequestration.

Original language	English
Pages (from-to)	1759–1777
Number of pages	19
Journal	The Biochemical Journal
Volume	482
Issue number	23
DOIs	https://doi.org/10.1042/BCJ20253431
Publication status	Published - Dec 2025

Keywords

allosteric regulation
calcium signalling
calmodulin
cell cycle
kinases

Access to Document

10.1042/BCJ20253431Licence: CC BY

Published versionFinal published version, 4.59 MBLicence: CC BY

Cite this

Horne, C. R., Wang, T., Young, S. N., Dite, T. A., Nyvall, H. G., Suresh, S., Davies, K. A., Gonzalez Castro, A., Vaibhav, V., Mather, L. J., Dagley, L. F., Belousoff, M. J., Manning, G., Means, A. R., Burke, J. E., Petersen, J., Scott, J. W., & Murphy, J. M. (2025). Unconventional binding of calmodulin to CHK2 kinase inhibits catalytic activity. The Biochemical Journal, 482(23), 1759–1777. https://doi.org/10.1042/BCJ20253431

@article{9add311dfd464354accb20a1292fae35,

title = "Unconventional binding of calmodulin to CHK2 kinase inhibits catalytic activity",

abstract = "Calmodulin (CaM) serves an essential role in eukaryotic cells as a Ca2+ sensor. Ca2+ binding leads to conformation changes in CaM that enable engagement of a repertoire of enzymes and the regulation of their catalytic activities. Classically, Ca2+-CaM binds to an inhibitory pseudosubstrate sequence C-terminal to the kinase domain in members of the Ca2+-CaM-dependent protein kinase (CAMK) family and relieves inhibition to promote catalytic activity. Here, we report an unexpected mechanism by which CaM can bind CHK2 kinase to inhibit its kinase activity. Using biochemical, biophysical and structural mass spectrometry, we identify a direct interaction of Ca2+-CaM with the CHK2 kinase domain that suppresses CHK2 catalytic activity in vitro and identify K373 in CHK2 as crucial for cell proliferation in human cells following DNA damage. Our findings add direct suppression of kinase activity to the repertoire of CaM's functions, complementing the paradigmatic mechanism of promoting kinase activity through autoinhibitory domain sequestration.",

keywords = "allosteric regulation, calcium signalling, calmodulin, cell cycle, kinases",

author = "Horne, {Christopher R.} and Tingting Wang and Young, {Samuel N.} and Dite, {Toby A.} and Nyvall, {Hunter G.} and Sushant Suresh and Davies, {Katherine A.} and {Gonzalez Castro}, Abner and Vineet Vaibhav and Mather, {Lucy J.} and Dagley, {Laura F.} and Belousoff, {Matthew J.} and Gerard Manning and Means, {Anthony R.} and Burke, {John E.} and Janni Petersen and Scott, {John W.} and Murphy, {James M.}",

year = "2025",

month = dec,

doi = "10.1042/BCJ20253431",

language = "English",

volume = "482",

pages = "1759–1777",

journal = "The Biochemical Journal",

issn = "0264-6021",

publisher = "Portland Press Ltd",

number = "23",

}

Horne, CR, Wang, T, Young, SN, Dite, TA, Nyvall, HG, Suresh, S, Davies, KA, Gonzalez Castro, A, Vaibhav, V, Mather, LJ, Dagley, LF, Belousoff, MJ, Manning, G, Means, AR, Burke, JE, Petersen, J, Scott, JW & Murphy, JM 2025, 'Unconventional binding of calmodulin to CHK2 kinase inhibits catalytic activity', The Biochemical Journal, vol. 482, no. 23, pp. 1759–1777. https://doi.org/10.1042/BCJ20253431

TY - JOUR

T1 - Unconventional binding of calmodulin to CHK2 kinase inhibits catalytic activity

AU - Horne, Christopher R.

AU - Wang, Tingting

AU - Young, Samuel N.

AU - Dite, Toby A.

AU - Nyvall, Hunter G.

AU - Suresh, Sushant

AU - Davies, Katherine A.

AU - Gonzalez Castro, Abner

AU - Vaibhav, Vineet

AU - Mather, Lucy J.

AU - Dagley, Laura F.

AU - Belousoff, Matthew J.

AU - Manning, Gerard

AU - Means, Anthony R.

AU - Burke, John E.

AU - Petersen, Janni

AU - Scott, John W.

AU - Murphy, James M.

PY - 2025/12

Y1 - 2025/12

N2 - Calmodulin (CaM) serves an essential role in eukaryotic cells as a Ca2+ sensor. Ca2+ binding leads to conformation changes in CaM that enable engagement of a repertoire of enzymes and the regulation of their catalytic activities. Classically, Ca2+-CaM binds to an inhibitory pseudosubstrate sequence C-terminal to the kinase domain in members of the Ca2+-CaM-dependent protein kinase (CAMK) family and relieves inhibition to promote catalytic activity. Here, we report an unexpected mechanism by which CaM can bind CHK2 kinase to inhibit its kinase activity. Using biochemical, biophysical and structural mass spectrometry, we identify a direct interaction of Ca2+-CaM with the CHK2 kinase domain that suppresses CHK2 catalytic activity in vitro and identify K373 in CHK2 as crucial for cell proliferation in human cells following DNA damage. Our findings add direct suppression of kinase activity to the repertoire of CaM's functions, complementing the paradigmatic mechanism of promoting kinase activity through autoinhibitory domain sequestration.

AB - Calmodulin (CaM) serves an essential role in eukaryotic cells as a Ca2+ sensor. Ca2+ binding leads to conformation changes in CaM that enable engagement of a repertoire of enzymes and the regulation of their catalytic activities. Classically, Ca2+-CaM binds to an inhibitory pseudosubstrate sequence C-terminal to the kinase domain in members of the Ca2+-CaM-dependent protein kinase (CAMK) family and relieves inhibition to promote catalytic activity. Here, we report an unexpected mechanism by which CaM can bind CHK2 kinase to inhibit its kinase activity. Using biochemical, biophysical and structural mass spectrometry, we identify a direct interaction of Ca2+-CaM with the CHK2 kinase domain that suppresses CHK2 catalytic activity in vitro and identify K373 in CHK2 as crucial for cell proliferation in human cells following DNA damage. Our findings add direct suppression of kinase activity to the repertoire of CaM's functions, complementing the paradigmatic mechanism of promoting kinase activity through autoinhibitory domain sequestration.

KW - allosteric regulation

KW - calcium signalling

KW - calmodulin

KW - cell cycle

KW - kinases

UR - http://www.scopus.com/inward/record.url?scp=105023862365&partnerID=8YFLogxK

U2 - 10.1042/BCJ20253431

DO - 10.1042/BCJ20253431

M3 - Article

C2 - 41003242

AN - SCOPUS:105023862365

SN - 0264-6021

VL - 482

SP - 1759

EP - 1777

JO - The Biochemical Journal

JF - The Biochemical Journal

IS - 23

ER -

Unconventional binding of calmodulin to CHK2 kinase inhibits catalytic activity

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this