GO:1990573 potassium ion import across plasma membrane: Transport Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1990573 describes the directed movement of potassium ions from outside a cell, across the plasma membrane, and into the cytosol.
• Potassium import is essential for maintaining membrane potential, cell volume, and intracellular pH in virtually all cell types.
• Key molecular players include the KdpFABC complex in bacteria and P-type ATPases such as the Na+/K+-ATPase in eukaryotes.
• Structural studies have revealed the architecture and ion-release mechanisms of potassium-importing complexes, including KdpFABC and PIB-4-type ATPases.
• Dysregulation of potassium import is linked to human diseases such as hypertension, cardiac arrhythmias, and neurological disorders.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable precise interrogation of genes mediating potassium import.
Description
Potassium ion import across plasma membrane (GO:1990573) is a fundamental biological process that ensures the directed movement of potassium ions from the extracellular space into the cytosol. This process is critical for establishing and maintaining the resting membrane potential, regulating cell volume, and supporting secondary active transport of other solutes. In bacteria, potassium import is mediated by dedicated systems such as the KdpFABC complex, which has been structurally characterized to reveal its ion-transport mechanism. In eukaryotic cells, the Na+/K+-ATPase (a P-type ATPase) couples ATP hydrolysis to the exchange of sodium and potassium ions, effectively importing potassium while exporting sodium. The physiological importance of potassium import is underscored by the severe consequences of its dysfunction, including cardiac arrhythmias and neurological disorders. Understanding the molecular details of this process is therefore essential for both basic cell biology and therapeutic development.
potassium ion import across plasma membrane At A Glance
| GO ID | GO:1990573 |
|---|---|
| GO term | potassium ion import across plasma membrane |
| Ontology | biological_process |
| Synonym | potassium import, potassium ion import, potassium ion uptake |
| Major function | Directed movement of potassium ions from the extracellular space into the cytosol across the plasma membrane |
| Cellular context | Plasma membrane of prokaryotic and eukaryotic cells |
| Representative proteins | KdpFABC complex, Na+/K+-ATPase (ATP1A1), PIB-4-type ATPases |
| Energy coupling | Primary active transport (ATP hydrolysis) or secondary active transport |
| Physiological roles | Membrane potential maintenance, cell volume regulation, pH homeostasis, secondary transport |
What Is GO:1990573?
GO:1990573, potassium ion import across plasma membrane, is defined as the directed movement of potassium ions from outside of a cell, across the plasma membrane, and into the cytosol. This process is a type of potassium ion transport that specifically results in the net accumulation of potassium within the cell, often against its concentration gradient, and is distinct from potassium export or intracellular potassium trafficking.
Why Is potassium ion import across plasma membrane Important in Cell Biology?
Potassium ion import across the plasma membrane is indispensable for life. It sets the resting membrane potential that underlies nerve impulse conduction, muscle contraction, and hormone secretion. In bacteria, potassium import systems such as KdpFABC allow survival under potassium-limiting conditions and contribute to osmotic stress responses. In humans, the Na+/K+-ATPase, which imports two potassium ions while exporting three sodium ions per ATP hydrolyzed, is a major consumer of cellular energy and a target for drugs like digitalis. Mutations in the ATP1A1 gene, encoding the Na+/K+-ATPase α1 subunit, cause diseases including hypertension and cardiac arrhythmias. Moreover, potassium import is intertwined with proton transport, as the Na+/K+-ATPase can also mediate proton import, affecting intracellular pH. Thus, understanding this process has broad implications for physiology, pharmacology, and disease mechanisms.
• Maintains resting membrane potential essential for nerve and muscle function.
• Regulates cell volume and prevents osmotic stress.
• Supports secondary active transport of nutrients and ions.
• Dysfunction linked to cardiac arrhythmias and hypertension.
• Mutations in ATP1A1 cause neurological and endocrine disorders.
• Bacterial potassium import is a target for novel antibiotics.
• Proton import via Na+/K+-ATPase affects intracellular pH.
• Potassium import is critical for plant salt tolerance and growth.
• Structural insights enable rational drug design.
• CRISPR screens can identify novel regulators of potassium import.
What Happens During potassium ion import across plasma membrane?
Recognition and binding of potassium ions at the extracellular side
In simple terms: The transporter first grabs potassium ions from outside the cell.
Potassium import begins when the transport protein, such as the KdpFABC complex or the Na+/K+-ATPase, binds potassium ions from the extracellular environment with high affinity. In the KdpFABC system, the KdpA subunit is responsible for potassium binding and selectivity. In the Na+/K+-ATPase, potassium ions bind to the E2 state of the pump after sodium ions are released to the outside. This binding step is highly specific and ensures that only potassium ions are imported.
Conformational change and ion occlusion
In simple terms: The transporter changes shape to trap the potassium ions inside.
Upon potassium binding, the transporter undergoes a conformational change that occludes the ions from the extracellular space. For the Na+/K+-ATPase, this involves the transition from the E2-P state to the E2 state, which has a high affinity for potassium. Structural studies of PIB-4-type ATPases have revealed how ion release and occlusion are coupled to phosphorylation and dephosphorylation events. In KdpFABC, the binding of potassium to KdpA triggers a series of conformational changes that are transmitted to the KdpB subunit, which hydrolyzes ATP.
Translocation across the membrane
In simple terms: The ions are moved through the protein channel across the membrane.
The occluded potassium ions are translocated across the plasma membrane through a pathway formed by the transmembrane domains of the transporter. In the Na+/K+-ATPase, this movement is coupled to the counter-transport of sodium ions and is driven by ATP hydrolysis. The KdpFABC complex uses a similar mechanism, with the KdpA subunit forming the ion pathway and the KdpB subunit providing the energy through ATP hydrolysis. The rate of translocation can be modulated by factors such as membrane potential and ion concentrations.
Release of potassium ions into the cytosol
In simple terms: The ions are released inside the cell.
Once the transporter reaches the inward-facing conformation, potassium ions are released into the cytosol. For the Na+/K+-ATPase, this occurs upon dephosphorylation of the pump, which returns it to the E1 state with low affinity for potassium. In PIB-4-type ATPases, ion release is triggered by dephosphorylation and is accompanied by proton import in some cases. The released potassium ions then contribute to the cytosolic potassium pool, influencing membrane potential and cell volume.
Proton import as a coupled process
In simple terms: Sometimes protons are brought in along with potassium.
In some transporters, potassium import is coupled to proton import. For example, the Na+/K+-ATPase can mediate proton import during Na+/K+ exchange, which affects intracellular pH. This proton import pathway is distinct from the classical Na+/K+ exchange and may have implications for cellular pH regulation under physiological and pathological conditions. Understanding these coupled processes is important for fully appreciating the role of potassium import in cellular homeostasis.
Key Genes Involved in GO:1990573 potassium ion import across plasma membrane
The following genes and proteins are central to potassium ion import across the plasma membrane, as evidenced by structural, biochemical, and genetic studies.
| Gene | Major Role | Research Relevance |
|---|---|---|
| KdpA | Potassium-binding subunit of the KdpFABC complex | Structural studies reveal ion selectivity and binding |
| KdpB | ATP-hydrolyzing subunit of the KdpFABC complex | Provides energy for potassium import |
| KdpC | Accessory subunit of the KdpFABC complex | Stabilizes the complex and aids assembly |
| KdpF | Small subunit of the KdpFABC complex | May regulate complex activity |
| ATP1A1 | α1 subunit of Na+/K+-ATPase | Mutations cause hypertension and cardiac arrhythmias |
| ATP1A2 | α2 subunit of Na+/K+-ATPase | Expressed in muscle and neurons; involved in calcium signaling |
| ATP1A3 | α3 subunit of Na+/K+-ATPase | Mutations linked to neurological disorders |
| ATP1B1 | β1 subunit of Na+/K+-ATPase | Chaperone and regulatory functions |
| ATP1B2 | β2 subunit of Na+/K+-ATPase | Expressed in glia; involved in cell adhesion |
| FXYD1 | Regulatory subunit of Na+/K+-ATPase | Modulates pump activity in heart and muscle |
| FXYD2 | Regulatory subunit of Na+/K+-ATPase | Mutations cause hypomagnesemia |
| FXYD3 | Regulatory subunit of Na+/K+-ATPase | Overexpressed in some cancers |
| FXYD4 | Regulatory subunit of Na+/K+-ATPase | Regulates sodium transport in kidney |
| FXYD5 | Regulatory subunit of Na+/K+-ATPase | Involved in cell adhesion and cancer |
| FXYD6 | Regulatory subunit of Na+/K+-ATPase | Modulates pump kinetics |
| FXYD7 | Regulatory subunit of Na+/K+-ATPase | Expressed in brain; regulates neuronal excitability |
| PIB-4-type ATPases | Family of potassium-importing ATPases | Structural and mechanistic studies |
How Is potassium ion import across plasma membrane Regulated?
Potassium ion import across the plasma membrane is tightly regulated at multiple levels. The activity of the Na+/K+-ATPase is modulated by its regulatory subunits, the FXYD proteins, which can alter ion affinity and transport rate in a tissue-specific manner. Hormones such as insulin and aldosterone regulate pump abundance and activity. In bacteria, the expression of the KdpFABC operon is induced under potassium limitation and osmotic stress, controlled by the KdpD/KdpE two-component system. Additionally, intracellular pH and proton import can influence potassium import, as the Na+/K+-ATPase can mediate proton transport. Post-translational modifications, including phosphorylation, also regulate pump trafficking and function.
potassium ion import across plasma membrane and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ATP1A1 | Hypertension, cardiac arrhythmias | Knock-in mouse models with patient mutations |
| ATP1A2 | Familial hemiplegic migraine | Point-mutation knock-in in neurons |
| ATP1A3 | Rapid-onset dystonia-parkinsonism | CRISPR knockout in dopaminergic neurons |
| KdpA | Bacterial potassium uptake | Knockout in E. coli for growth assays |
| FXYD2 | Hypomagnesemia | Overexpression in kidney cell lines |
Cardiac arrhythmias and hypertension
Mutations in ATP1A1, encoding the α1 subunit of the Na+/K+-ATPase, are associated with hypertension and cardiac arrhythmias. The pump's role in maintaining the resting membrane potential of cardiomyocytes means that even subtle changes in its activity can predispose to arrhythmias. Additionally, autoantibodies against the Na+/K+-ATPase have been implicated in preeclampsia and hypertension. Understanding these mutations through CRISPR models can reveal genotype-phenotype relationships.
Neurological disorders
Mutations in ATP1A2 and ATP1A3 cause familial hemiplegic migraine and rapid-onset dystonia-parkinsonism, respectively. These disorders highlight the critical role of potassium import in neuronal excitability and neurotransmitter release. The Na+/K+-ATPase maintains the ionic gradients necessary for action potentials, and its dysfunction leads to aberrant neuronal signaling. Proton import via the pump may also contribute to pH dysregulation in neurons.
Bacterial infections and antibiotic resistance
The KdpFABC complex is essential for bacterial survival under potassium-limiting conditions, such as those encountered in the host. Targeting this system could lead to novel antibiotics. Structural insights into KdpFABC provide a basis for rational drug design. Additionally, PIB-4-type ATPases in bacteria are potential drug targets.
From potassium ion import across plasma membrane-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ATP1A1 affect membrane potential? | CRISPR knockout in cardiomyocytes |
| How do point mutations in ATP1A2 alter pump kinetics? | Knock-in of patient mutations in HEK293 cells |
| Can KdpFABC be targeted by antibiotics? | Bacterial knockout and susceptibility testing |
| What is the role of FXYD proteins in pump regulation? | Overexpression of FXYD subunits in Xenopus oocytes |
| Does proton import via Na+/K+-ATPase affect pH? | Point mutation of proton-binding residues |
| Can CRISPR screen identify novel potassium import regulators? | Genome-wide knockout library in mammalian cells |
How to Study the potassium ion import across plasma membrane Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Patch-clamp | Ion currents | Kinetics of Na+/K+-ATPase |
| Cryo-EM | Protein structure | KdpFABC architecture |
| X-ray crystallography | Atomic structure | PIB-4-type ATPase mechanism |
| Fluorescent potassium indicators | Intracellular K+ concentration | Live-cell imaging of import |
| pH-sensitive dyes | Intracellular pH | Proton import via Na+/K+-ATPase |
| CRISPR screen | Gene function | Identify regulators of potassium import |
| RNA-seq | Gene expression | Transcriptional response to potassium stress |
| Proteomics | Protein abundance | Quantify pump subunits |
Electrophysiology
Patch-clamp and two-electrode voltage-clamp techniques measure the electrical currents generated by potassium import, such as the transient currents mediated by the Na+/K+-ATPase. These methods provide real-time kinetic data on ion transport and can be used to study mutant pumps.
Structural biology
X-ray crystallography and cryo-electron microscopy have elucidated the structures of the KdpFABC complex and PIB-4-type ATPases, revealing the molecular basis of ion binding, occlusion, and release. These techniques are essential for understanding conformational changes during transport.
Fluorescence-based ion imaging
Genetically encoded potassium indicators and pH-sensitive dyes allow real-time monitoring of intracellular potassium and proton concentrations in live cells. These methods can assess the impact of mutations on potassium import and proton import.
CRISPR screening
Genome-wide CRISPR knockout or activation screens can identify genes that regulate potassium import, as demonstrated by single-nuclear transcriptome analysis of vascular smooth muscle cells. Such screens can uncover novel transporters or regulatory pathways.
How CRISPR Can Be Used to Study GO:1990573 potassium ion import across plasma membrane
Knockout
CRISPR knockout of genes such as ATP1A1 or KdpA can abolish potassium import, leading to loss of membrane potential and cell death. These models are useful for studying the essentiality of specific transporters and for identifying compensatory mechanisms. For example, knockout of ATP1A1 in cardiomyocytes would reveal its role in cardiac excitability.
Point Mutation
Introducing disease-associated point mutations (e.g., in ATP1A1 or ATP1A2) via CRISPR base editing or homology-directed repair allows precise modeling of altered pump function. Such models can be used to test the effects of mutations on ion affinity, transport rate, and drug sensitivity.
Knock-in
Knock-in of tagged versions of potassium transporters (e.g., GFP-tagged ATP1A1) enables live-cell imaging and proteomic analysis. Knock-in of reporter genes under the control of the KdpFABC promoter can monitor expression in bacteria. These models facilitate studies of protein localization and dynamics.
Overexpression
Overexpression of potassium import genes, such as FXYD subunits or ATP1A1, can be achieved by CRISPR activation or lentiviral delivery. Overexpression models are useful for studying gain-of-function effects, drug screening, and the consequences of pump hyperactivity.
How EDITGENE Supports potassium ion import across plasma membrane Research
Researchers studying potassium ion import across plasma membrane-related genes often need to determine whether a candidate gene is causally involved in ion transport, membrane potential regulation, or disease. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell models, enabling rigorous functional studies.
Contact EDITGENE today to design your custom CRISPR model for potassium ion import across plasma membrane research.
Frequently Asked Questions About potassium ion import across plasma membrane
What is GO:1990573?
GO:1990573 is the Gene Ontology term for potassium ion import across plasma membrane, defined as the directed movement of potassium ions from outside a cell, across the plasma membrane, and into the cytosol.
What genes are involved in potassium ion import across plasma membrane?
Key genes include KdpA, KdpB, KdpC, KdpF in bacteria, and ATP1A1, ATP1A2, ATP1A3, ATP1B1, and FXYD family members in humans.
How does the Na+/K+-ATPase import potassium?
The Na+/K+-ATPase couples ATP hydrolysis to the exchange of three sodium ions out and two potassium ions in, via a series of conformational changes (E1/E2).
What is the role of KdpFABC in potassium import?
KdpFABC is a high-affinity potassium import complex in bacteria, with KdpA binding potassium and KdpB hydrolyzing ATP to drive transport.
What diseases are associated with defective potassium import?
Mutations in ATP1A1 cause hypertension and cardiac arrhythmias; ATP1A2 and ATP1A3 mutations cause neurological disorders.
Can CRISPR be used to study potassium import?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models allow precise interrogation of genes involved in potassium import.
What methods measure potassium import?
Patch-clamp, fluorescent potassium indicators, pH-sensitive dyes, and structural biology techniques such as cryo-EM and X-ray crystallography.
Is proton import related to potassium import?
Yes, the Na+/K+-ATPase can mediate proton import during Na+/K+ exchange, affecting intracellular pH.
What are PIB-4-type ATPases?
PIB-4-type ATPases are a family of potassium-importing ATPases found in bacteria and archaea, structurally characterized to reveal ion-release mechanisms.
How can I create a knockout of ATP1A1?
EDITGENE provides custom CRISPR knockout services for ATP1A1 and other potassium import genes, with validated cell lines.
Conclusion
Potassium ion import across plasma membrane (GO:1990573) is a vital biological process that maintains ionic gradients, membrane potential, and cellular homeostasis. Structural and functional studies of the KdpFABC complex and Na+/K+-ATPase have illuminated the molecular mechanisms of ion binding, translocation, and release. Dysregulation of this process is linked to cardiovascular and neurological diseases, making it a compelling target for therapeutic intervention. CRISPR-based models offer powerful tools to dissect the genetic basis of potassium import and to identify novel regulatory pathways. EDITGENE's comprehensive services support researchers in generating precise cell models to advance this field.
References
- 1. Huang CS et al.. 2017. Crystal structure of the potassium-importing KdpFABC membrane complex.. Nature 546(7660):681-685 PMID: 28636601
- 2. Grønberg C et al.. 2021. Structure and ion-release mechanism of P(IB-4)-type ATPases.. Elife 10 PMID: 34951590
- 3. Biondo ED et al.. 2021. Diseases caused by mutations in the Na(+)/K(+) pump α1 gene ATP1A1.. Am J Physiol Cell Physiol 321(2):C394-C408 PMID: 34232746
- 4. Moreno C et al.. 2020. Transient Electrical Currents Mediated by the Na(+)/K(+)-ATPase: A Tour from Basic Biophysics to Human Diseases.. Biophys J 119(2):236-242 PMID: 32579966
- 6. Shen Y et al.. 2023. Identification of Novel Gene Regulatory Networks for Dystrophin Protein in Vascular Smooth Muscle Cells by Single-Nuclear Transcriptome Analysis.. Cells 12(6) PMID: 36980233
- 8. Vedovato N et al.. 2014. Route, mechanism, and implications of proton import during Na+/K+ exchange by native Na+/K+-ATPase pumps.. J Gen Physiol 143(4):449-64 PMID: 24688018
