| Title: |
LITAF regulates action potential duration by modulating NEDD4‐1‐mediated degradation of L‐type calcium channels |
| Authors: |
Moshal, Karni S; Roder, Karim; Kabakov, Anatoli; Turan, Nilüfer N; Xie, An; Werdich, Andreas A; Kim, Tae Yun; Cooper, Leroy L; Lu, Yichun; Terentyev, Dmitry; Choi, Bum‐Rak; MacRae, Calum A; Koren, Gideon |
| Contributors: |
National Heart, Lung, and Blood Institute |
| Source: |
The FASEB Journal ; volume 33, issue S1 ; ISSN 0892-6638 1530-6860 |
| Publisher Information: |
Wiley |
| Publication Year: |
2019 |
| Collection: |
Wiley Online Library (Open Access Articles via Crossref) |
| Description: |
Rationale The QT interval is a predictor of arrhythmias and sudden cardiac death. A genetic variant upstream of the gene encoding LITAF (lipopolysaccharide‐induced tumor necrosis factor) is associated with a prolonged QT interval. Objective We sought to determine the role of LITAF in modulating cardiac excitation at the cellular and organ levels. Methods and Results Morpholino knockdown of LITAF in zebrafish embryos resulted in a robust increase in calcium transients in optically mapped hearts, which primarily depends on calcium influx. Adenovirally expressed LITAF shortened action potential duration and lowered Cava1c expression in neonatal rabbit cardiomyocytes, whereas a shRNA‐mediated LITAF knockdown had the opposite effect. Using whole‐cell patch clamping and western blotting of 3‐week old rabbit cardiomyocytes, overexpressed LITAF resulted in a decrease in I Ca,L and Cava1c expression, whereas a LITAF knockdown increased I Ca,L and Cava1c protein levels. Live‐cell confocal calcium imaging detected a decrease in calcium transients in LITAF‐overexpressing adult rabbit cardiomyocytes, which was accompanied by lower Cava1c expression. In tsA201 cells, overexpressed LITAF downregulated the total and surface pools of Cava1c via increased Cava1c ubiquitination and subsequent lysosomal degradation. Co‐immunoprecipitation and immunofluorescence experiments showed complex formation and co‐localization of LITAF and L‐type calcium channels (LTCC) in tsA201 cells and adult rabbit cardiomyocytes, respectively. In tsA201 cells, NEDD4‐1, but not its catalytically inactive form NEDD4‐1‐C867A, increased Cava1c ubiquitination compared to control. Cava1c ubiquitination was further increased by co‐expressed LITAF and NEDD4‐1 but not NEDD4‐1‐C867A. Finally, adenovirally co‐expressed NEDD4‐1 shRNA abolished the negative effect of LITAF on I Ca,L and Cava1c expression in 3‐week old rabbit cardiomyocytes. Conclusions The data suggest that LITAF promotes NEDD4‐1‐mediated ubiquitination and subsequent degradation of cardiac LTCC, ... |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1096/fasebj.2019.33.1_supplement.824.19 |
| Availability: |
http://dx.doi.org/10.1096/fasebj.2019.33.1_supplement.824.19 |
| Rights: |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
| Accession Number: |
edsbas.C3607F6D |
| Database: |
BASE |