Differential Modulation of SK Channel Subtypes by Phosphorylation

Authors

Young-Woo Nam, Chapman University
Dezhi Kong, Hebei Medical University
Dong Wang, Chapman University
Razan Orfali, Chapman UniversityFollow
Rinzhin T. Sherpa, Chapman UniversityFollow
Jennifer Totonchy, Chapman UniversityFollow
Surya M. Nauli, Chapman UniversityFollow
Miao Zhang, Chapman UniversityFollow

Document Type

Article

Publication Date

1-6-2021

Abstract

Small-conductance Ca²⁺-activated K⁺ (SK) channels are voltage-independent and are activated by Ca²⁺ binding to the calmodulin constitutively associated with the channels. Both the pore-forming subunits and the associated calmodulin are subject to phosphorylation. Here, we investigated the modulation of different SK channel subtypes by phosphorylation, using the cultured endothelial cells as a tool. We report that casein kinase 2 (CK2) negatively modulates the apparent Ca²⁺ sensitivity of SK1 and IK channel subtypes by more than 5-fold, whereas the apparent Ca²⁺ sensitivity of the SK3 and SK2 subtypes is only reduced by ∼2-fold, when heterologously expressed on the plasma membrane of cultured endothelial cells. The SK2 channel subtype exhibits limited cell surface expression in these cells, partly as a result of the phosphorylation of its C-terminus by cyclic AMP-dependent protein kinase (PKA). SK2 channels expressed on the ER and mitochondria membranes may protect against cell death. This work reveals the subtype-specific modulation of the apparent Ca²⁺ sensitivity and subcellular localization of SK channels by phosphorylation in cultured endothelial cells.

Comments

NOTICE: this is the author’s version of a work that was accepted for publication in Cell Calcium. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Cell Calcium, volume 94, in 2021. https://doi.org/10.1016/j.ceca.2020.102346

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Recommended Citation

Nam Y-W, Kong D, Wang D, et al. Differential modulation of SK channel subtypes by phosphorylation. Cell Calcium. 2021;94:102346. https://doi.org/10.1016/j.ceca.2020.102346

Copyright

Elsevier

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.