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14-3-3 promotes sarcolemmal expression of cardiac CaV1.2 and nucleates isoproterenol-triggered channel superclustering.

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Title: 14-3-3 promotes sarcolemmal expression of cardiac CaV1.2 and nucleates isoproterenol-triggered channel superclustering.
Authors: Spooner, Heather C.1, Costa, Alexandre D.1, Westhoff, Maartje1, Hernández-González, Adriana1, Ibrahimkhail, Husna1, Yarov-Yarovoy, Vladimir1,2, Horne, Mary C.3, Dickson, Eamonn J.1, Dixon, Rose E.1 redickson@ucdavis.edu
Source: Proceedings of the National Academy of Sciences of the United States of America. 2/4/2025, Vol. 122 Issue 5, p1-24. 36p.
Subjects: Ion channels, Potassium channels, Calcium channels, High resolution imaging, Isoproterenol
Abstract: The L-type Ca2+ channel (CaV1.2) is essential for cardiac excitation-contraction coupling. To contribute to the inward Ca2+ flux that drives Ca2+-induced- Ca2+- release, CaV1.2 channels must be expressed on the sarcolemma; thus the regulatory mechanisms that tune CaV1.2 expression to meet contractile demand are an emerging area of research. A ubiquitously expressed protein called 14-3- 3 has been proposed to affect Ca2+ channel trafficking in nonmyocytes; however, whether 14-3- 3 has similar effects on CaV1.2 in cardiomyocytes is unknown. 14-3- 3 preferentially binds phospho-serine/threonine residues to affect many cellular processes and is known to regulate cardiac ion channels including NaV1.5 and the human ether-à- go- go- related gene (hERG) potassium channel. Altered 14-3- 3 expression and function have been implicated in cardiac pathologies including hypertrophy. Accordingly, we tested the hypothesis that 14-3- 3 interacts with CaV1.2 in a phosphorylation-dependent manner and regulates cardiac CaV1.2 trafficking and recycling. Confocal imaging, proximity ligation assays, superresolution imaging, and coimmunoprecipitation revealed a population of 14-3- 3 colocalized and closely associated with CaV1.2. The degree of 14-3- 3/CaV1.2 colocalization increased upon stimulation of β-adrenergic receptors with isoproterenol. Notably, only the 14-3- 3- associated CaV1.2 population displayed increased cluster size with isoproterenol, revealing a role for 14-3- 3 as a nucleation factor that directs CaV1.2 superclustering. Isoproterenol-stimulated augmentation of sarcolemmal CaV1.2 expression, Ca2+ currents, and Ca2+ transients in ventricular myocytes were strengthened by 14-3- 3 overexpression and attenuated by 14-3- 3 inhibition. These data support a model where 14-3- 3 interacts with CaV1.2 in a phosphorylation-dependent manner to promote enhanced trafficking/recycling, clustering, and activity during β-adrenergic stimulation. [ABSTRACT FROM AUTHOR]
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Abstract:The L-type Ca2+ channel (CaV1.2) is essential for cardiac excitation-contraction coupling. To contribute to the inward Ca2+ flux that drives Ca2+-induced- Ca2+- release, CaV1.2 channels must be expressed on the sarcolemma; thus the regulatory mechanisms that tune CaV1.2 expression to meet contractile demand are an emerging area of research. A ubiquitously expressed protein called 14-3- 3 has been proposed to affect Ca2+ channel trafficking in nonmyocytes; however, whether 14-3- 3 has similar effects on CaV1.2 in cardiomyocytes is unknown. 14-3- 3 preferentially binds phospho-serine/threonine residues to affect many cellular processes and is known to regulate cardiac ion channels including NaV1.5 and the human ether-à- go- go- related gene (hERG) potassium channel. Altered 14-3- 3 expression and function have been implicated in cardiac pathologies including hypertrophy. Accordingly, we tested the hypothesis that 14-3- 3 interacts with CaV1.2 in a phosphorylation-dependent manner and regulates cardiac CaV1.2 trafficking and recycling. Confocal imaging, proximity ligation assays, superresolution imaging, and coimmunoprecipitation revealed a population of 14-3- 3 colocalized and closely associated with CaV1.2. The degree of 14-3- 3/CaV1.2 colocalization increased upon stimulation of β-adrenergic receptors with isoproterenol. Notably, only the 14-3- 3- associated CaV1.2 population displayed increased cluster size with isoproterenol, revealing a role for 14-3- 3 as a nucleation factor that directs CaV1.2 superclustering. Isoproterenol-stimulated augmentation of sarcolemmal CaV1.2 expression, Ca2+ currents, and Ca2+ transients in ventricular myocytes were strengthened by 14-3- 3 overexpression and attenuated by 14-3- 3 inhibition. These data support a model where 14-3- 3 interacts with CaV1.2 in a phosphorylation-dependent manner to promote enhanced trafficking/recycling, clustering, and activity during β-adrenergic stimulation. [ABSTRACT FROM AUTHOR]
ISSN:00278424
DOI:10.1073/pnas.2413308122