GO:0098915 membrane repolarization during ventricular cardiac muscle cell action potential: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0098915 describes the biological process by which ventricular cardiomyocytes return from the positive peak of the action potential to the negative resting membrane potential through ion transport across the sarcolemma.
• Repolarization is driven by the coordinated decline of inward depolarizing currents and activation of outward potassium currents, including transient outward (Ito), rapid (IKr) and slow (IKs) delayed rectifier currents.
• The process is not uniform across the sarcolemma; cell-to-cell electrical interactions and regional differences influence early and late repolarization.
• Abnormal ventricular repolarization is a central mechanism in cardiac arrhythmia and long QT syndrome, making it a key research target.
• The electrocardiogram T wave is a clinical synonym for ventricular repolarization, linking cellular electrophysiology to non-invasive diagnostics.
• CRISPR-based knockout, point-mutation, knock-in and overexpression models enable causal testing of repolarization genes in ventricular cardiomyocytes.
Description
GO:0098915, membrane repolarization during ventricular cardiac muscle cell action potential, is the biological process in which ions are transported across the cardiomyocyte membrane so that the membrane potential moves from the positive peak of the action potential back toward the negative resting potential. This process is essential for every heartbeat because it resets the ventricular cell for the next excitation and determines the duration of the action potential and the QT interval on the electrocardiogram. Ventricular repolarization is not a single event but a tightly orchestrated balance of inward and outward currents, including the transient outward potassium current, the rapid and slow delayed rectifier potassium currents, and the decay of calcium and sodium currents. Because repolarization is spatially and temporally heterogeneous across the ventricular wall and sarcolemma, cell-to-cell electrical interactions further shape its time course. For researchers, GO:0098915 provides a precise ontology anchor for studying arrhythmia mechanisms, drug effects, and genetic variants that alter cardiac electrical stability. Understanding this term is therefore fundamental to cardiac electrophysiology, translational cardiology, and the development of gene-edited cell models.
membrane repolarization during ventricular cardiac muscle cell action potential At A Glance
| GO ID | GO:0098915 |
|---|---|
| GO term | membrane repolarization during ventricular cardiac muscle cell action potential |
| Ontology | biological_process |
| Synonym | electrocardiogram T wave; regulation of ventricular cardiac muscle repolarization; ventricular repolarization |
| Major function | Returns the ventricular cardiomyocyte membrane potential from the action potential peak toward the negative resting potential via ion transport |
| Primary ions/currents | Potassium efflux via Ito, IKr and IKs; decline of inward calcium and sodium currents |
| Cellular location | Ventricular cardiomyocyte sarcolemma |
| Clinical readout | Electrocardiogram T wave and QT interval |
| Disease relevance | Long QT syndrome, cardiac arrhythmia and abnormal repolarization syndromes |
What Is GO:0098915?
In simple terms, GO:0098915 is the process that switches a ventricular heart muscle cell off after it has fired. More formally, it is the ion-transport process that changes the ventricular cardiomyocyte membrane potential from the positive value reached at the peak of the action potential toward the negative resting potential. This repolarization phase depends on the balance between depolarizing inward currents and repolarizing outward potassium currents, and it is reflected clinically as the T wave of the electrocardiogram.
Why Is membrane repolarization during ventricular cardiac muscle cell action potential Important in Cell Biology?
GO:0098915 is important because ventricular repolarization determines the electrical silence that follows each heartbeat and directly controls action potential duration, the QT interval, and susceptibility to arrhythmia. When repolarization is delayed or heterogeneous, the heart becomes vulnerable to early afterdepolarizations and reentrant excitation, which are mechanisms of life-threatening ventricular arrhythmias. Because repolarization reserve is a measurable property of ventricular myocytes, it is a key concept for drug safety and for interpreting genetic variants in ion channel and trafficking genes.
• Defines the return of ventricular cardiomyocytes to resting membrane potential after excitation.
• Controls action potential duration and the QT interval on the electrocardiogram.
• Depends on a balance of outward potassium currents and declining inward currents.
• Shows regional and cell-to-cell heterogeneity that affects arrhythmia substrate.
• Is impaired in long QT syndrome and other inherited arrhythmia disorders.
• Is a central mechanism in acquired cardiac arrhythmia and drug-induced QT prolongation.
• Provides a target for testing gene variants in ion channels and trafficking proteins.
• Can be modeled in human induced pluripotent stem cell-derived cardiomyocytes using CRISPR editing.
• Links cellular electrophysiology to clinical T wave morphology.
• Supports safety pharmacology and repolarization reserve assessment.
What Happens During membrane repolarization during ventricular cardiac muscle cell action potential?
Phase 1: Early repolarization and transient outward current
In simple terms: The first quick drop in voltage happens when potassium leaves the cell through transient outward channels.
After the rapid upstroke of the ventricular action potential, the transient outward potassium current Ito contributes to early phase 1 repolarization. This current helps set the initial notch of the action potential and influences the subsequent plateau and repolarization time course. In heart failure, changes in transient outward potassium channel expression can alter repolarization and contribute to arrhythmia.
Phase 2: Plateau and balance of inward and outward currents
In simple terms: During the plateau, calcium coming in and potassium going out are nearly balanced, so the voltage stays high for a while.
The plateau phase is maintained by a fine balance between inward calcium current and outward potassium currents. Single-cell voltage clamp studies have been essential for dissecting these individual current components in ventricular myocytes. In silico action potential models show that the plateau and repolarization phases are governed by current-voltage-time relationships and repolarization reserve.
Phase 3: Rapid repolarization by delayed rectifier potassium currents
In simple terms: The cell rapidly returns to its negative resting voltage as potassium flows out through delayed rectifier channels.
Phase 3 repolarization is driven primarily by activation of the rapid delayed rectifier current IKr and the slow delayed rectifier current IKs, together with inactivation of calcium channels. These currents are major determinants of action potential duration and repolarization reserve. Abnormalities in these currents are directly linked to long QT syndrome and arrhythmia risk.
Spatial heterogeneity and cell-to-cell interactions
In simple terms: Different parts of the heart muscle cell, and neighboring cells, do not repolarize at exactly the same time.
Repolarization is not uniform within the sarcolemma of in situ ventricular cardiomyocytes, and regional differences contribute to the dispersion of repolarization. Cell-to-cell electrical interactions during early and late repolarization further modulate the time course and can influence arrhythmogenesis. This heterogeneity is important because increased dispersion of repolarization is a substrate for reentrant arrhythmia.
Clinical correlation: the T wave
In simple terms: The T wave on an ECG is the body-surface signature of ventricular repolarization.
The electrocardiogram T wave is a clinical synonym for ventricular repolarization and reflects the summed repolarization of ventricular myocytes. Abnormal T wave morphology and QT prolongation are markers of abnormal repolarization and are used in diagnosis and drug safety assessment. Long QT syndrome genetics has clarified how ion channel variants alter repolarization and increase arrhythmia susceptibility.
Key Genes Involved in GO:0098915 membrane repolarization during ventricular cardiac muscle cell action potential
The genes most relevant to GO:0098915 encode ion channel subunits, accessory proteins and trafficking factors that shape ventricular repolarization.
| Gene | Major Role | Research Relevance |
|---|---|---|
| KCNH2 | Alpha subunit of the rapid delayed rectifier potassium channel IKr | Major long QT syndrome gene; central to phase 3 repolarization |
| KCNQ1 | Alpha subunit of the slow delayed rectifier potassium channel IKs | Long QT syndrome gene; contributes to repolarization reserve |
| KCNE1 | Beta subunit modulating IKs | Modifies IKs kinetics and repolarization |
| KCNE2 | Beta subunit modulating IKr | Modifies IKr and drug sensitivity |
| SCN5A | Alpha subunit of the cardiac sodium channel | Inward sodium current influences plateau and repolarization |
| CACNA1C | Alpha subunit of the L-type calcium channel | Inward calcium current maintains plateau; inactivation permits repolarization |
| KCND3 | Alpha subunit of the transient outward potassium channel Ito | Contributes to early repolarization and action potential notch |
| KCNIP2 | Accessory subunit of Ito | Modulates Ito expression and kinetics |
| KCNJ2 | Inward rectifier potassium channel IK1 | Sets resting potential and final repolarization |
| FGF13 | Fibroblast growth factor homologous factor regulating sodium channel and connexin trafficking | Regulates impulse propagation and repolarization-related electrical coupling |
| GJA1 | Connexin 43 gap junction protein | Mediates cell-to-cell electrical interactions during repolarization |
| ANK2 | Ankyrin-B cytoskeletal adaptor | Organizes ion channels and transporters in cardiomyocytes |
| AKAP9 | A-kinase anchoring protein 9 | Scaffolds signaling complexes that regulate ion channels |
| CALM1 | Calmodulin 1 | Regulates calcium-dependent inactivation of channels |
| CALM2 | Calmodulin 2 | Regulates calcium-dependent inactivation of channels |
| CALM3 | Calmodulin 3 | Regulates calcium-dependent inactivation of channels |
| SNTA1 | Syntrophin alpha 1 | Part of the sodium channel macromolecular complex |
How Is membrane repolarization during ventricular cardiac muscle cell action potential Regulated?
Ventricular repolarization is regulated by the expression, trafficking and phosphorylation of ion channel subunits, and by the balance between depolarizing and repolarizing currents. Repolarization reserve describes the capacity of the cell to maintain repolarization when one current is reduced, and it is influenced by the interplay of IKr, IKs and Ito. Cell-to-cell electrical interactions and gap junction trafficking further modulate the repolarization time course. Genetic variants in channel and accessory genes can alter these regulatory processes and predispose to arrhythmia.
membrane repolarization during ventricular cardiac muscle cell action potential and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| KCNH2 | Long QT syndrome type 2; reduced IKr delays repolarization | Knockout or point-mutation hiPSC-derived cardiomyocytes |
| KCNQ1 | Long QT syndrome type 1; reduced IKs impairs repolarization reserve | Knock-in of patient variant in hiPSC-derived cardiomyocytes |
| SCN5A | Long QT syndrome type 3 and Brugada syndrome; altered sodium current | Point-mutation knock-in cardiomyocyte model |
| KCND3 | Altered Ito and early repolarization; heart failure remodeling | Overexpression or knockout in ventricular cardiomyocytes |
| FGF13 | Impaired sodium channel and connexin trafficking; electrical propagation defects | Knockout and tagged knock-in cardiomyocyte models |
Long QT syndrome and inherited arrhythmia
Long QT syndrome is caused by variants that delay ventricular repolarization, often through loss-of-function of potassium currents or gain-of-function of inward currents. These changes prolong the action potential and QT interval and increase the risk of torsades de pointes and sudden cardiac death. GO:0098915 provides the ontology framework for interpreting these variants in cellular models.
Abnormal repolarization and cardiac arrhythmia
Abnormal repolarization is a central mechanism of cardiac arrhythmia, including early afterdepolarizations and reentrant excitation. Increased dispersion of repolarization across the ventricular wall contributes to arrhythmia substrate. Experimental models that manipulate repolarization currents are therefore important for mechanistic studies.
Heart failure and electrical remodeling
Heart failure is associated with changes in transient outward potassium channel expression and other repolarization currents, which can alter action potential duration and arrhythmia susceptibility. These electrical remodeling changes are relevant to GO:0098915 because they directly affect the repolarization process.
From membrane repolarization during ventricular cardiac muscle cell action potential-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a potassium channel gene delay repolarization? | Knockout hiPSC-derived ventricular cardiomyocytes |
| Does a patient variant alter IKr or IKs kinetics? | Point-mutation knock-in hiPSC-derived cardiomyocytes |
| Can a fluorescent tag report channel trafficking? | Tagged knock-in of the channel gene |
| Does overexpression of an accessory subunit change action potential duration? | Overexpression in ventricular cardiomyocytes |
| Does a gap junction gene affect cell-to-cell repolarization? | Knockout or knockdown of GJA1 in cardiomyocyte cultures |
| Can repolarization reserve be quantified in vitro? | Voltage clamp and action potential recording in edited cardiomyocytes |
How to Study the membrane repolarization during ventricular cardiac muscle cell action potential Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Patch-clamp voltage clamp | Individual ionic currents such as Ito, IKr and IKs | Quantify repolarization currents in edited cardiomyocytes |
| Current-clamp action potential recording | Action potential duration and repolarization time | Assess repolarization phenotype after gene editing |
| Optical mapping | Spatial and temporal repolarization patterns | Measure dispersion of repolarization in monolayers |
| Multi-electrode array | Field potential duration and arrhythmia-like events | High-throughput screening of edited cardiomyocytes |
| In silico action potential modeling | Predicted current-voltage-time relationships | Estimate repolarization reserve and drug effects |
| Immunofluorescence imaging | Channel and connexin localization | Assess trafficking defects in edited cells |
| Western blot | Protein expression of channel subunits | Confirm knockout or overexpression efficiency |
| RNA sequencing | Transcript levels of repolarization genes | Detect electrical remodeling in disease models |
Patch-clamp electrophysiology
Single-cell voltage clamp is the classic method for measuring the individual ionic currents that underlie ventricular repolarization. It allows researchers to quantify Ito, IKr, IKs and other currents and to test how genetic edits alter them. Action potential recordings in current clamp provide a direct readout of repolarization time.
Action potential and repolarization mapping
Optical mapping and multi-electrode arrays can measure repolarization time and dispersion across cardiomyocyte monolayers or tissue preparations. These approaches reveal spatial heterogeneity and cell-to-cell interactions that are not captured in single-cell recordings.
In silico action potential modeling
Computational models of the ventricular action potential integrate current-voltage-time relationships to predict repolarization behavior and repolarization reserve. Such models are useful for hypothesis generation before experimental validation.
CRISPR-edited cardiomyocyte models
Human induced pluripotent stem cell-derived cardiomyocytes carrying CRISPR knockout, point mutations or knock-ins allow causal testing of repolarization genes. These models can be combined with electrophysiology and imaging to link genotype to repolarization phenotype.
How CRISPR Can Be Used to Study GO:0098915 membrane repolarization during ventricular cardiac muscle cell action potential
Knockout
CRISPR knockout of repolarization genes such as KCNH2 or KCNQ1 in cardiomyocytes can reveal their contribution to action potential duration and repolarization reserve. Knockout models are useful for loss-of-function studies and for validating gene essentiality in electrical function.
Point Mutation
Point-mutation knock-in of patient variants in genes such as SCN5A or KCNH2 allows precise modeling of long QT syndrome and other repolarization disorders. These models preserve endogenous regulatory context and are ideal for testing variant-specific electrophysiological effects.
Knock-in
Tagged knock-in of channel or trafficking genes, such as FGF13 or GJA1, enables visualization of protein localization and trafficking in cardiomyocytes. Knock-in reporters can also be used to monitor gene expression during repolarization studies.
Overexpression
Overexpression of accessory subunits or ion channels can test gain-of-function effects on repolarization and action potential duration. This approach is useful for studying electrical remodeling and for validating therapeutic targets.
How EDITGENE Supports membrane repolarization during ventricular cardiac muscle cell action potential Research
Researchers studying membrane repolarization during ventricular cardiac muscle cell action potential-related genes often need to determine whether a candidate gene is causally involved in setting action potential duration, repolarization reserve or arrhythmia susceptibility. EDITGENE provides CRISPR-based cell model services that allow precise manipulation of these genes in relevant cardiomyocyte backgrounds.
Contact EDITGENE today to design your custom CRISPR model for membrane repolarization during ventricular cardiac muscle cell action potential research.
Frequently Asked Questions About membrane repolarization during ventricular cardiac muscle cell action potential
What is GO:0098915?
GO:0098915 is the biological process of membrane repolarization during ventricular cardiac muscle cell action potential, in which ion transport returns the ventricular cardiomyocyte membrane potential from the action potential peak toward the negative resting potential.
What is ventricular repolarization?
Ventricular repolarization is the phase of the cardiac action potential in which ventricular myocytes return to their negative resting potential, and it is reflected clinically as the T wave on the electrocardiogram.
What genes are involved in ventricular repolarization?
Key genes include KCNH2, KCNQ1, KCNE1, KCNE2, SCN5A, CACNA1C, KCND3, KCNIP2, KCNJ2, FGF13 and GJA1, which encode ion channel subunits and regulatory proteins.
Which ion currents drive repolarization?
Repolarization is driven by outward potassium currents including Ito, IKr and IKs, together with inactivation of inward calcium and sodium currents.
How is ventricular repolarization measured?
It can be measured by patch-clamp electrophysiology, action potential recording, optical mapping, multi-electrode arrays and in silico modeling.
What is repolarization reserve?
Repolarization reserve is the capacity of the cardiomyocyte to maintain repolarization when one current is reduced, and it depends on the balance of IKr, IKs and Ito.
How does abnormal repolarization cause arrhythmia?
Abnormal repolarization can cause early afterdepolarizations and increased dispersion of repolarization, which are substrates for reentrant arrhythmia.
What diseases are linked to GO:0098915?
Long QT syndrome, cardiac arrhythmia and heart failure-related electrical remodeling are linked to abnormal ventricular repolarization.
Can CRISPR be used to study ventricular repolarization?
Yes, CRISPR knockout, point-mutation knock-in and overexpression in cardiomyocytes allow causal testing of repolarization genes and patient variants.
Why is the T wave important?
The T wave is the electrocardiographic manifestation of ventricular repolarization, and its morphology and timing are used to assess repolarization abnormalities and drug effects.
Conclusion
GO:0098915 provides a precise ontology definition for ventricular repolarization, a process that is central to cardiac electrical stability and clinically reflected in the T wave and QT interval. Its mechanism depends on the coordinated activity of multiple ion currents and is modulated by spatial heterogeneity and cell-to-cell interactions. CRISPR-based cell models are powerful tools for dissecting the genetic basis of repolarization and for translating findings into arrhythmia research.
References
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