| Autor: |
Zou X; Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, United States., Shanmugam SK; Department of Physiology and Cellular Biophysics, Columbia University, New York, United States., Kanner SA; Doctoral Program in Neurobiology and Behavior, Columbia University, New York, United States., Sampson KJ; Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, United States., Kass RS; Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, United States., Colecraft HM; Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, United States.; Doctoral Program in Neurobiology and Behavior, Columbia University, New York, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
ELife [Elife] 2023 Aug 31; Vol. 12. Date of Electronic Publication: 2023 Aug 31. |
| DOI: |
10.7554/eLife.83466 |
| Abstrakt: |
The slow delayed rectifier potassium current, I Ks , conducted through pore-forming Q1 and auxiliary E1 ion channel complexes is important for human cardiac action potential repolarization. During exercise or fright, I Ks is up-regulated by protein kinase A (PKA)-mediated Q1 phosphorylation to maintain heart rhythm and optimum cardiac performance. Sympathetic up-regulation of I Ks requires recruitment of PKA holoenzyme (two regulatory - RI or RII - and two catalytic Cα subunits) to Q1 C-terminus by an A kinase anchoring protein (AKAP9). Mutations in Q1 or AKAP9 that abolish their functional interaction result in long QT syndrome type 1 and 11, respectively, which increases the risk of sudden cardiac death during exercise. Here, we investigated the utility of a targeted protein phosphorylation (TPP) approach to reconstitute PKA regulation of I Ks in the absence of AKAP9. Targeted recruitment of endogenous Cα to E1-YFP using a GFP/YFP nanobody (nano) fused to RIIα enabled acute cAMP-mediated enhancement of I Ks , reconstituting physiological regulation of the channel complex. By contrast, nano-mediated tethering of RIIα or Cα to Q1-YFP constitutively inhibited I Ks by retaining the channel intracellularly in the endoplasmic reticulum and Golgi. Proteomic analysis revealed that distinct phosphorylation sites are modified by Cα targeted to Q1-YFP compared to free Cα. Thus, functional outcomes of synthetically recruited PKA on I Ks regulation is critically dependent on the site of recruitment within the channel complex. The results reveal insights into divergent regulation of I Ks by phosphorylation across different spatial and time scales, and suggest a TPP approach to develop new drugs to prevent exercise-induced sudden cardiac death.
Competing Interests: XZ, SS, SK, KS, RK No competing interests declared, HC Reviewing editor, eLife
(© 2023, Zou, Shanmugam, Kanner et al.) |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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