GO:1905001 negative regulation of membrane repolarization during atrial cardiac muscle cell action potential: Atrial Repolarization Control, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1905001 describes any process that stops, prevents, or reduces the frequency, rate, or extent of membrane repolarization during an atrial cardiac muscle cell action potential.
• It is a biological_process term whose synonyms include negative regulation of atrial repolarization and negative regulation of electrocardiogram QRS complex.
• Repolarization in atrial myocytes depends on the coordinated activity of potassium channels such as Kv1.5, Kv4.3, and SK2, whose surface delivery and localization are tightly controlled.
• Ion transport proteins, including Na+/Ca2+ exchangers, shape the cytosolic calcium and membrane potential changes that underlie repolarization timing.
• Dysregulation of atrial repolarization is mechanistically linked to atrial arrhythmias, making this term relevant to atrial fibrillation research.
• CRISPR knockout, point-mutation, knock-in, and overexpression models enable causal testing of genes proposed to regulate atrial repolarization.
Description
GO:1905001, negative regulation of membrane repolarization during atrial cardiac muscle cell action potential, is a Gene Ontology biological_process term that captures any process which stops, prevents, or reduces the frequency, rate, or extent of membrane repolarization specifically in atrial cardiac muscle cells. Repolarization is the phase of the cardiac action potential during which the cell returns to its resting membrane potential, and its precise timing is essential for normal atrial electrical function. The term therefore sits at the intersection of ion channel biology, membrane trafficking, and cardiac electrophysiology.
negative regulation of membrane repolarization during atrial cardiac muscle cell action potential At A Glance
| GO ID | GO:1905001 |
|---|---|
| GO term | negative regulation of membrane repolarization during atrial cardiac muscle cell action potential |
| Ontology | biological_process |
| Synonym | negative regulation of atrial repolarization; inhibition of atrial repolarization; downregulation of electrocardiogram QRS complex |
| Major function | Suppression or delay of membrane repolarization in atrial cardiac muscle cells |
| Related cellular context | Atrial cardiac muscle cell sarcolemma and ion channel complexes |
| Related molecular players | Potassium channels (e.g., Kv1.5, Kv4.3, SK2), Na+/Ca2+ exchanger, cytoskeletal adaptor proteins |
| Disease relevance | Atrial arrhythmias including atrial fibrillation |
| Research methods | CRISPR KO, point mutation, knock-in, overexpression, electrophysiology, imaging |
What Is GO:1905001?
In plain terms, GO:1905001 describes the biological brakes on atrial repolarization. The QuickGO definition states: Any process that stops, prevents or reduces the frequency, rate or extent of membrane repolarization during atrial cardiac muscle cell action potential. This means the term covers molecular events that delay or suppress the return of the atrial myocyte membrane potential to its resting state after depolarization, including modulation of potassium currents, calcium handling, and ion channel surface expression.
Why Is negative regulation of membrane repolarization during atrial cardiac muscle cell action potential Important in Cell Biology?
Understanding GO:1905001 is important because the duration and amplitude of atrial repolarization determine the atrial refractory period, which in turn influences susceptibility to re-entrant arrhythmias such as atrial fibrillation. Proteins that control the surface expression and localization of repolarizing potassium channels, including SK2 and Kv channel isoforms, directly modulate this process. In addition, calcium handling proteins such as the Na+/Ca2+ exchanger influence the cytosolic calcium and membrane potential changes that shape repolarization timing. Consequently, genes annotated to this term are candidate modulators of atrial electrical stability and potential targets for antiarrhythmic research.
• Defines the regulatory brake on atrial repolarization, a key determinant of atrial refractory period.
• Provides an ontology framework for annotating genes that delay or suppress atrial myocyte repolarization.
• Links ion channel trafficking and cytoskeletal adaptor proteins to atrial electrical function.
• Connects calcium handling and Na+/Ca2+ exchange to repolarization timing in cardiac myocytes.
• Supports mechanistic research into atrial fibrillation and other atrial arrhythmias.
• Enables systematic comparison of atrial versus ventricular repolarization regulation.
• Guides CRISPR-based causal testing of candidate repolarization-modifying genes.
• Helps interpret electrocardiogram QRS complex-related phenotypes in model systems.
• Facilitates drug discovery efforts targeting atrial-selective ion channels.
• Provides a searchable entity for AI-driven literature and database retrieval.
What Happens During negative regulation of membrane repolarization during atrial cardiac muscle cell action potential?
Initiation of the atrial action potential and the repolarization phase
In simple terms: The atrial cell first fires an electrical signal, and then needs to reset itself; this term is about slowing that reset.
During an atrial cardiac muscle cell action potential, depolarization is followed by repolarization, the phase in which the membrane potential returns toward resting values. Negative regulation of this repolarization phase means that molecular processes reduce the rate or extent of this return. The timing of repolarization depends on the balance of inward and outward currents, including potassium currents carried by channels such as Kv1.5 and Kv4.3, whose delivery to the membrane surface is regulated in cardiac myocytes.
Potassium channel surface expression and trafficking
In simple terms: The channels that let potassium out to reset the cell must be delivered to the right place on the cell surface.
The number of functional potassium channels at the sarcolemma is a major determinant of repolarization capacity. Myosin-V motor proteins participate in the selective delivery of Kv channel isoforms to the membrane surface of cardiac myocytes, thereby influencing the available repolarizing current. In addition, the small-conductance calcium-activated potassium channel SK2 has its surface membrane expression enhanced by interacting proteins such as alpha-actinin2 and filamin A, which act through distinct subcellular mechanisms. These trafficking and anchoring events can modulate how quickly atrial cells repolarize.
Calcium handling and Na+/Ca2+ exchange
In simple terms: Calcium levels inside the cell affect the electrical reset, and the exchanger that moves calcium helps set that timing.
Cytosolic calcium and the Na+/Ca2+ exchanger are important for cardiac myocyte electrical activity. Characterization of the relationship between Na+/Ca2+ exchange rate and cytosolic calcium in cardiac myocytes has shown how tightly these two are coupled. Because calcium-sensitive currents and exchangers can influence membrane potential, changes in calcium handling may contribute to negative regulation of atrial repolarization.
Integration into the atrial action potential waveform
In simple terms: All these effects combine to change the shape and duration of the atrial electrical signal.
The net effect of reduced or delayed repolarizing current is prolongation of the atrial action potential and alteration of the electrocardiogram QRS complex, which is reflected in the synonyms of GO:1905001. Proteins that enhance SK2 surface expression, such as alpha-actinin2 and filamin A, can increase repolarizing capacity and thus oppose negative regulation, whereas conditions that reduce potassium channel delivery can promote it. The integration of these molecular events determines atrial refractory properties.
Key Genes Involved in GO:1905001 negative regulation of membrane repolarization during atrial cardiac muscle cell action potential
The following genes and proteins have been experimentally linked to processes that influence atrial repolarization, ion channel trafficking, or cardiac calcium handling, and are therefore relevant to GO:1905001.
| Gene | Major Role | Research Relevance |
|---|---|---|
| KCNC2 (SK2) | Calcium-activated potassium channel; surface expression enhanced by alpha-actinin2 and filamin A | Modulates repolarizing current in cardiac myocytes |
| ACTN2 (alpha-actinin2) | Cytoskeletal adaptor that enhances SK2 surface membrane expression | Regulates ion channel localization |
| FLNA (filamin A) | Actin-binding protein that enhances SK2 surface expression via a distinct mechanism | Cytoskeletal control of channel trafficking |
| KCNA5 (Kv1.5) | Voltage-gated potassium channel isoform delivered to cardiac myocyte membrane | Contributes to repolarizing current |
| KCND3 (Kv4.3) | Voltage-gated potassium channel isoform delivered to cardiac myocyte membrane | Contributes to repolarizing current |
| MYO5A (Myosin-Va) | Motor protein involved in selective delivery of Kv channel isoforms | Regulates channel surface targeting |
| MYO5B (Myosin-Vb) | Motor protein implicated in Kv channel delivery | Regulates channel surface targeting |
| SLC8A1 (NCX1) | Na+/Ca2+ exchanger influencing cytosolic calcium and membrane potential | Links calcium handling to repolarization |
| CALM1 (Calmodulin) | Calcium sensor that can modulate ion channel activity | Potential regulator of calcium-dependent currents |
| KCNJ2 (Kir2.1) | Inward rectifier potassium channel contributing to resting potential | Sets background for repolarization |
| KCNH2 (hERG) | Potassium channel contributing to repolarization in cardiac cells | Comparator for atrial versus ventricular repolarization |
| SCN5A (Nav1.5) | Sodium channel responsible for depolarization upstroke | Defines the start of the action potential |
| CACNA1C (Cav1.2) | L-type calcium channel contributing to plateau phase | Influences repolarization timing |
| ATP2A2 (SERCA2) | Sarcoplasmic reticulum calcium ATPase | Modulates cytosolic calcium and electrical activity |
| RYR2 | Ryanodine receptor mediating calcium release | Affects calcium-dependent currents |
| GJA1 (Connexin 43) | Gap junction protein for electrical coupling | Influences tissue-level repolarization |
| GJA5 (Connexin 40) | Atrial gap junction protein | Atrial-specific electrical coupling |
How Is negative regulation of membrane repolarization during atrial cardiac muscle cell action potential Regulated?
Regulation of atrial repolarization involves multiple layers. At the channel level, surface expression of SK2 is enhanced by interacting proteins alpha-actinin2 and filamin A through distinct subcellular mechanisms, providing a means to tune repolarizing current. At the trafficking level, myosin-V motor proteins selectively deliver Kv channel isoforms to the cardiac myocyte membrane surface, thereby controlling the available potassium current. At the calcium handling level, the Na+/Ca2+ exchange rate is tightly related to cytosolic calcium, which can influence membrane potential and thus repolarization. These mechanisms together determine whether repolarization is accelerated or suppressed.
negative regulation of membrane repolarization during atrial cardiac muscle cell action potential and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| KCNC2 (SK2) | Atrial arrhythmia susceptibility via repolarization modulation | Knockout and overexpression in atrial myocyte-like cells |
| ACTN2 | Cytoskeletal regulation of ion channel surface expression | Point mutation and knock-in models |
| FLNA | Channel trafficking and electrical stability | Knockout and tagged knock-in |
| KCNA5 | Atrial repolarization current and arrhythmia risk | Knockout and overexpression |
| SLC8A1 | Calcium handling and electrical instability | Point mutation and knockout |
Atrial fibrillation and atrial arrhythmias
Atrial repolarization abnormalities are mechanistically linked to atrial fibrillation, the most common sustained cardiac arrhythmia. Because GO:1905001 describes suppression of atrial repolarization, genes that reduce repolarizing potassium currents or alter channel trafficking could promote arrhythmogenesis. The dependence of repolarization on Kv channel delivery and SK2 surface expression highlights candidate pathways for atrial-selective antiarrhythmic strategies.
Calcium handling disorders and electrical instability
Disturbances in cytosolic calcium and Na+/Ca2+ exchange can alter cardiac myocyte electrical behavior. Such disturbances may contribute to delayed afterdepolarizations and triggered activity, which are relevant to atrial arrhythmia mechanisms. Understanding how calcium handling intersects with negative regulation of atrial repolarization may reveal new therapeutic targets.
Electrocardiogram QRS complex phenotypes
The synonyms of GO:1905001 include negative regulation of electrocardiogram QRS complex, indicating a conceptual link between molecular repolarization control and surface electrocardiogram readouts. Research on ion channel trafficking and calcium handling can help explain how molecular changes translate into clinically observable electrical phenotypes.
From negative regulation of membrane repolarization during atrial cardiac muscle cell action potential-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a candidate gene delay atrial repolarization? | CRISPR knockout in atrial myocyte-like cells |
| Does a specific channel residue control repolarization timing? | CRISPR point mutation knock-in |
| Does tagging a channel protein alter its trafficking? | Tagged knock-in |
| Does increased expression of a regulator suppress repolarization? | CRISPR overexpression |
| Which genes modify atrial repolarization in a screen? | CRISPR library screening |
| How does a variant affect channel surface expression? | Knock-in plus imaging and electrophysiology |
How to Study the negative regulation of membrane repolarization during atrial cardiac muscle cell action potential Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Patch-clamp electrophysiology | Action potential duration and repolarization kinetics | Functional testing of CRISPR perturbations |
| Multielectrode array | Extracellular field potentials and conduction | Atrial arrhythmia models |
| Surface biotinylation | Membrane protein surface expression | Channel trafficking studies |
| Fluorescence imaging | Subcellular localization of tagged proteins | Knock-in and overexpression validation |
| Calcium imaging | Cytosolic calcium transients | Calcium handling studies |
| Na+/Ca2+ exchange assay | Exchange rate and calcium coupling | Ion transport characterization |
| RNA sequencing | Transcriptional changes | Candidate gene discovery |
| Proteomics | Protein abundance and interactions | Pathway analysis |
Electrophysiology and action potential recording
Patch-clamp and multielectrode array recordings measure action potential duration and repolarization kinetics in atrial myocyte models. These methods directly assess the functional output of genes annotated to GO:1905001 and can be combined with CRISPR perturbations to test causality.
Imaging of ion channel surface expression
Fluorescence imaging and surface biotinylation can quantify the membrane localization of channels such as SK2 and Kv isoforms. Such approaches have been used to show that alpha-actinin2 and filamin A enhance SK2 surface expression through distinct mechanisms and that myosin-V motors deliver Kv channels to the surface.
Calcium imaging and exchanger assays
Calcium imaging and Na+/Ca2+ exchange measurements reveal how cytosolic calcium dynamics relate to membrane potential changes. Characterization of the Na+/Ca2+ exchange rate and cytosolic calcium in cardiac myocytes provides a framework for linking calcium handling to repolarization.
Transcriptomic and proteomic profiling
RNA sequencing and proteomics can identify genes and proteins whose expression changes under conditions of altered atrial repolarization. These datasets help prioritize candidates for CRISPR validation and can reveal pathways that converge on GO:1905001.
How CRISPR Can Be Used to Study GO:1905001 negative regulation of membrane repolarization during atrial cardiac muscle cell action potential
Knockout
CRISPR knockout of candidate genes such as KCNC2, ACTN2, or FLNA can test whether their loss alters atrial repolarization. Because these proteins influence SK2 surface expression and channel trafficking, knockout models can reveal their contribution to negative regulation of atrial repolarization.
Point Mutation
Point mutations can be introduced into genes encoding ion channels or adaptor proteins to model specific residues implicated in trafficking or gating. Such models help determine whether a single amino acid change is sufficient to alter repolarization timing, building on evidence that distinct protein domains control SK2 surface expression.
Knock-in
Knock-in of tagged or variant alleles allows tracking of channel localization and function in atrial myocyte models. Tagged knock-in of Kv channel isoforms can be used to study the selective delivery mechanisms mediated by myosin-V motors.
Overexpression
CRISPR-mediated overexpression of regulators such as alpha-actinin2 or filamin A can enhance SK2 surface expression and potentially accelerate repolarization. Conversely, overexpression of dominant-negative trafficking factors can suppress repolarization, providing a gain-of-function approach to study GO:1905001.
How EDITGENE Supports negative regulation of membrane repolarization during atrial cardiac muscle cell action potential Research
Researchers studying negative regulation of membrane repolarization during atrial cardiac muscle cell action potential-related genes often need to determine whether a candidate gene is causally involved in controlling repolarization timing or whether it is merely correlated with electrical phenotypes. EDITGENE provides CRISPR-based cell model services that enable such causal testing in relevant cardiac cell backgrounds.
Contact EDITGENE today to design your custom CRISPR model for negative regulation of membrane repolarization during atrial cardiac muscle cell action potential research.
Frequently Asked Questions About negative regulation of membrane repolarization during atrial cardiac muscle cell action potential
What is GO:1905001?
GO:1905001 is a Gene Ontology biological_process term defined as any process that stops, prevents or reduces the frequency, rate or extent of membrane repolarization during atrial cardiac muscle cell action potential.
What does negative regulation of atrial repolarization mean?
It means molecular events that delay or suppress the return of the atrial cardiac muscle cell membrane potential to its resting state after an action potential.
What genes are involved in negative regulation of membrane repolarization during atrial cardiac muscle cell action potential?
Genes encoding potassium channels such as KCNC2 (SK2), KCNA5 (Kv1.5), and KCND3 (Kv4.3), cytoskeletal adaptors ACTN2 and FLNA, motor proteins MYO5A and MYO5B, and the Na+/Ca2+ exchanger SLC8A1 have been linked to processes influencing atrial repolarization.
How is SK2 channel surface expression regulated in cardiac cells?
SK2 surface membrane expression is enhanced by its interacting proteins alpha-actinin2 and filamin A through distinct subcellular mechanisms.
What role do myosin-V motor proteins play in cardiac repolarization?
Myosin-V motor proteins are involved in the selective delivery of Kv channel isoforms to the membrane surface of cardiac myocytes, thereby influencing repolarizing current.
How does Na+/Ca2+ exchange relate to cardiac repolarization?
The Na+/Ca2+ exchange rate is tightly related to cytosolic calcium in cardiac myocytes, and both can influence membrane potential changes that shape repolarization.
Why is atrial repolarization important for heart rhythm?
Atrial repolarization determines the atrial refractory period, which affects susceptibility to re-entrant arrhythmias such as atrial fibrillation.
What research methods are used to study GO:1905001?
Patch-clamp electrophysiology, multielectrode array, surface biotinylation, fluorescence imaging, calcium imaging, Na+/Ca2+ exchange assays, RNA sequencing, and proteomics are commonly used.
Can CRISPR be used to study atrial repolarization genes?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models allow causal testing of candidate genes in cardiac cell backgrounds.
What diseases are associated with abnormal atrial repolarization?
Atrial fibrillation and other atrial arrhythmias are associated with abnormal atrial repolarization, and calcium handling disorders can contribute to electrical instability.
Conclusion
GO:1905001 provides a precise ontology framework for the molecular processes that suppress or delay membrane repolarization in atrial cardiac muscle cells. Its relevance spans ion channel trafficking, cytoskeletal adaptor function, and calcium handling, with direct implications for atrial arrhythmia research. By combining CRISPR-based causal models with electrophysiology and imaging, researchers can dissect how specific genes contribute to this regulatory process and identify new targets for atrial-selective therapies.
References
- 1. Zhang Z et al.. 2017. Distinct subcellular mechanisms for the enhancement of the surface membrane expression of SK2 channel by its interacting proteins, α-actinin2 and filamin A.. J Physiol 595(7):2271-2284 PMID: 27779751
- 3. Schumacher-Bass SM et al.. 2014. Role for myosin-V motor proteins in the selective delivery of Kv channel isoforms to the membrane surface of cardiac myocytes.. Circ Res 114(6):982-92 PMID: 24508725
- 4. Hove-Madsen L et al.. 2001. Characterization of the relationship between Na+ -Ca2+ exchange rate and cytosolic calcium in trout cardiac myocytes.. Pflugers Arch 441(5):701-8 PMID: 11294253
