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Jansen LAR, Welch MA, Plant LD, Baro DJ. Crosstalk between PKA and PIAS3 regulates cardiac Kv4 channel SUMOylation. Cell Commun Signal 2024; 22:422. [PMID: 39223673 PMCID: PMC11367828 DOI: 10.1186/s12964-024-01795-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 08/16/2024] [Indexed: 09/04/2024] Open
Abstract
Post-translational SUMOylation of nuclear and cytosolic proteins maintains homeostasis in eukaryotic cells and orchestrates programmed responses to changes in metabolic demand or extracellular stimuli. In excitable cells, SUMOylation tunes the biophysical properties and trafficking of ion channels. Ion channel SUMOylation status is determined by the opposing enzyme activities of SUMO ligases and deconjugases. Phosphorylation also plays a permissive role in SUMOylation. SUMO deconjugases have been identified for several ion channels, but their corresponding E3 ligases remain unknown. This study shows PIAS3, a.k.a. KChAP, is a bona fide SUMO E3 ligase for Kv4.2 and HCN2 channels in HEK cells, and endogenous Kv4.2 and Kv4.3 channels in cardiomyocytes. PIAS3-mediated SUMOylation at Kv4.2-K579 increases channel surface expression through a rab11a-dependent recycling mechanism. PKA phosphorylation at Kv4.2-S552 reduces the current mediated by Kv4 channels in HEK293 cells, cardiomyocytes, and neurons. This study shows PKA mediated phosphorylation blocks Kv4.2-K579 SUMOylation in HEK cells and cardiomyocytes. Together, these data identify PIAS3 as a key downstream mediator in signaling cascades that control ion channel surface expression.
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Affiliation(s)
| | - Meghyn A Welch
- Department of Biology, Georgia State University, Atlanta, GA, USA
- Present Address: Section on Molecular Neurophysiology and Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Leigh D Plant
- Department of Pharmaceutical Sciences, Center for Drug Discovery, Northeastern University, Boston, MA, USA
| | - Deborah J Baro
- Department of Biology, Georgia State University, Atlanta, GA, USA.
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Rahm AK, Hackbarth J, Müller ME, Pfeiffer J, Gampp H, Petersenn F, Rivinius R, Frey N, Lugenbiel P, Thomas D. Differential Effects of the Betablockers Carvedilol, Metoprolol and Bisoprolol on Cardiac K v4.3 (I to) Channel Isoforms. Int J Mol Sci 2023; 24:13842. [PMID: 37762145 PMCID: PMC10530285 DOI: 10.3390/ijms241813842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/03/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Cardiac Kv4.3 channels contribute to the transient outward K+ current, Ito, during early repolarization of the cardiac action potential. Two different isoforms of Kv4.3 are present in the human ventricle and exhibit differential remodeling in heart failure (HF). Cardioselective betablockers are a cornerstone of HF with reduced ejection fraction therapy as well as ventricular arrhythmia treatment. In this study we examined pharmacological effects of betablockers on both Kv4.3 isoforms to explore their potential for isoform-specific therapy. Kv4.3 isoforms were expressed in Xenopus laevis oocytes and incubated with the respective betablockers. Dose-dependency and biophysical characteristics were examined. HEK 293T-cells were transfected with the two Kv4.3 isoforms and analyzed with Western blots. Carvedilol (100 µM) blocked Kv4.3 L by 77 ± 2% and Kv4.3 S by 67 ± 6%, respectively. Metoprolol (100 µM) was less effective with inhibition of 37 ± 3% (Kv4.3 L) and 35 ± 4% (Kv4.3 S). Bisoprolol showed no inhibitory effect. Current reduction was not caused by changes in Kv4.3 protein expression. Carvedilol inhibited Kv4.3 channels at physiologically relevant concentrations, affecting both isoforms. Metoprolol showed a weaker blocking effect and bisoprolol did not exert an effect on Kv4.3. Blockade of repolarizing Kv4.3 channels by carvedilol and metoprolol extend their pharmacological mechanism of action, potentially contributing beneficial antiarrhythmic effects in normal and failing hearts.
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Affiliation(s)
- Ann-Kathrin Rahm
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Juline Hackbarth
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Mara E. Müller
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Julia Pfeiffer
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Heike Gampp
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Finn Petersenn
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Rasmus Rivinius
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Norbert Frey
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Patrick Lugenbiel
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Dierk Thomas
- Heidelberg Center for Heart Rhythm Disorders, Heidelberg University Hospital, 69120 Heidelberg, Germany (M.E.M.); (R.R.); (P.L.)
- Department of Cardiology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
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Wu LY, Song YJ, Zhang CL, Liu J. K V Channel-Interacting Proteins in the Neurological and Cardiovascular Systems: An Updated Review. Cells 2023; 12:1894. [PMID: 37508558 PMCID: PMC10377897 DOI: 10.3390/cells12141894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
KV channel-interacting proteins (KChIP1-4) belong to a family of Ca2+-binding EF-hand proteins that are able to bind to the N-terminus of the KV4 channel α-subunits. KChIPs are predominantly expressed in the brain and heart, where they contribute to the maintenance of the excitability of neurons and cardiomyocytes by modulating the fast inactivating-KV4 currents. As the auxiliary subunit, KChIPs are critically involved in regulating the surface protein expression and gating properties of KV4 channels. Mechanistically, KChIP1, KChIP2, and KChIP3 promote the translocation of KV4 channels to the cell membrane, accelerate voltage-dependent activation, and slow the recovery rate of inactivation, which increases KV4 currents. By contrast, KChIP4 suppresses KV4 trafficking and eliminates the fast inactivation of KV4 currents. In the heart, IKs, ICa,L, and INa can also be regulated by KChIPs. ICa,L and INa are positively regulated by KChIP2, whereas IKs is negatively regulated by KChIP2. Interestingly, KChIP3 is also known as downstream regulatory element antagonist modulator (DREAM) because it can bind directly to the downstream regulatory element (DRE) on the promoters of target genes that are implicated in the regulation of pain, memory, endocrine, immune, and inflammatory reactions. In addition, all the KChIPs can act as transcription factors to repress the expression of genes involved in circadian regulation. Altered expression of KChIPs has been implicated in the pathogenesis of several neurological and cardiovascular diseases. For example, KChIP2 is decreased in failing hearts, while loss of KChIP2 leads to increased susceptibility to arrhythmias. KChIP3 is increased in Alzheimer's disease and amyotrophic lateral sclerosis, but decreased in epilepsy and Huntington's disease. In the present review, we summarize the progress of recent studies regarding the structural properties, physiological functions, and pathological roles of KChIPs in both health and disease. We also summarize the small-molecule compounds that regulate the function of KChIPs. This review will provide an overview and update of the regulatory mechanism of the KChIP family and the progress of targeted drug research as a reference for researchers in related fields.
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Affiliation(s)
- Le-Yi Wu
- Department of Pathophysiology, Shenzhen University Medical School, Shenzhen 518060, China
| | - Yu-Juan Song
- Department of Pathophysiology, Shenzhen University Medical School, Shenzhen 518060, China
| | - Cheng-Lin Zhang
- Department of Pathophysiology, Shenzhen University Medical School, Shenzhen 518060, China
| | - Jie Liu
- Department of Pathophysiology, Shenzhen University Medical School, Shenzhen 518060, China
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Bellotti AA, Murphy JG, O’Leary TS, Hoffman DA. Transport between im/mobile fractions shapes the speed and profile of cargo distribution in neurons. BIOPHYSICAL REPORTS 2022; 2:100082. [PMID: 36425667 PMCID: PMC9680811 DOI: 10.1016/j.bpr.2022.100082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/13/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Neuronal function requires continuous distribution of ion channels and other proteins throughout large cell morphologies. Protein distribution is complicated by immobilization of freely diffusing subunits such as on lipid rafts or in postsynaptic densities. Here, we infer rates of immobilization for the voltage-gated potassium channel Kv4.2. Fluorescence recovery after photobleaching quantifies protein diffusion kinetics, typically reported as a recovery rate and mobile fraction. We show that, implicit in the fluorescence recovery, are rates of particle transfer between mobile and immobile fractions (im/mobilization). We performed photobleaching of fluorescein-tagged ion channel Kv4.2-sGFP2 in over 450 dendrites of rat hippocampal cells. Using mass-action models, we infer rates of Kv4.2-sGFP2 im/mobilization. Using a realistic neuron morphology, we show how these rates shape the speed and profile of subunit distribution. The experimental protocol and model inference introduced here is widely applicable to other cargo and experimental systems.
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Affiliation(s)
- Adriano A. Bellotti
- Department of Engineering, University of Cambridge, Cambridge, UK
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Jonathan G. Murphy
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | | | - Dax A. Hoffman
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
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