Related Experiment Video
Updated: Jul 30, 2025
07:14
Subcellular Imaging of Neuronal Calcium Handling In Vivo
Published on: March 17, 2023
1.3K
Differential Control of Small-conductance Calcium-activated Potassium Channel Diffusion by Actin in Different
Shiju Gu1, Anastasios V Tzingounis1,2, George Lykotrafitis1,3
1Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA.
Function (Oxford, England)
|May 11, 2023
Summary
Actin filaments and membrane crowding restrict the diffusion of small-conductance calcium-activated potassium (SK) channels in neurons. This impacts SK channel localization and function, particularly at the axon initial segment during maturation.
Area of Science:
- Neuroscience
- Cell Biology
- Ion Channel Physiology
Background:
- Small-conductance calcium-activated potassium (SK) channels are crucial for regulating neuronal excitability and synaptic plasticity.
- While SK channel physiology and expression are studied, their membrane diffusion dynamics remain largely unknown.
- SK channel diffusion influences their proximity to calcium channels, affecting activation and neuronal function.
Purpose of the Study:
- To investigate the diffusion dynamics of SK channels in the neuronal plasma membrane.
- To identify factors controlling SK channel mobility, including actin cytoskeleton and membrane crowding.
- To understand how SK channel diffusion changes during neuronal maturation and in specific compartments like the axon initial segment (AIS).
Main Methods:
- Single-particle tracking (SPT) combined with total internal reflection fluorescence microscopy (TIRFm).
- Labeling of SK channels with quantum dots (QDs) for visualization.
- Experiments conducted on human embryonic kidney (HEK) cells and dissociated hippocampal neurons.
Main Results:
- Actin filaments significantly impede SK channel diffusion, reducing their diffusion coefficient.
- SK channel diffusion is progressively inhibited in somatodendritic compartments during neuronal maturation.
- Axon barriers restrict SK channel diffusion at the AIS around 6 days *in vitro*; strong immobilization occurs post-maturation, independent of actin.
Conclusions:
- Actin cytoskeleton and membrane crowding are key regulators of SK channel diffusion in neurons.
- Dynamic changes in SK channel mobility occur during neuronal development and are compartment-specific.
- Understanding SK channel diffusion provides insights into their functional localization and regulation within neuronal networks.
Related Concept Videos
01:19The Role of Ion Channels in Neuronal Computation
3.3K
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
3.3K
01:27Feedback Regulation of Calcium Concentration
3.4K
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
3.4K
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
2.3K
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
2.3K
01:21Electrochemical Gradient and Channel Proteins: An Overview
2.4K
An electrochemical gradient is a fundamental concept in biology and chemistry. It regulates the movement of ions across cell membranes. This movement is influenced by two factors:
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to...
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to...
2.4K
01:12Mechanically-gated Ion Channels
6.5K
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...
6.5K
01:41Action Potentials
131.8K
Overview
131.8K