Related Experiment Video

Updated: Jun 10, 2026

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes
10:19

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes

Published on: January 10, 2011

Current inhibition of human EAG1 potassium channels by the Ca2+ binding protein S100B

Nirakar Sahoo1, Jessica Tröger, Stefan H Heinemann

  • 1Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University of Jena, Jena, Germany. nirakarbiot@gmail.com

FEBS Letters
|August 17, 2010
PubMed

Insights

The acidic calcium-binding protein S100B inhibits human ether à go-go (hEAG1) potassium channels in a calcium-dependent manner. S100B shares binding sites with calmodulin, suggesting it acts as an alternative calcium sensor for hEAG1 channels.

Area of Science:

  • Molecular biology
  • Neuroscience
  • Biochemistry

Background:

  • Voltage-dependent human ether à go-go (hEAG1) potassium channels play roles in neuronal signaling and cancer cell proliferation.
  • Intracellular calcium (Ca2+) regulates hEAG1 channel activity through calmodulin (CaM) binding to its N- and C-termini.

Purpose of the Study:

  • To investigate the effect of the acidic calcium-binding protein S100B on hEAG1 channel activity.
  • To determine if S100B interacts with hEAG1 channels and shares binding sites with CaM.

Main Methods:

  • Inside-out patch-clamp electrophysiology in Xenopus oocytes to measure hEAG1 channel activity.
  • Protein pull-down assays to assess S100B-hEAG1 interaction.
  • Fluorescence correlation spectroscopy (FCS) to analyze binding site competition between S100B and CaM.

Main Results:

  • S100B application inhibited hEAG1 channels in a Ca2+-dependent manner.
  • Protein pull-down assays confirmed that S100B binds to hEAG1.
  • FCS data indicated that S100B and CaM bind to the same sites on hEAG1.

Conclusions:

  • S100B acts as a Ca2+-dependent inhibitor of hEAG1 potassium channels.
  • S100B represents a potential alternative calcium-sensing mechanism for hEAG1 channels, distinct from CaM.

More Related Videos

High-Throughput Optical Controlling and Recording Calcium Signal in iPSC-Derived Cardiomyocytes for Toxicity Testing and Phenotypic Drug Screening10:01

High-Throughput Optical Controlling and Recording Calcium Signal in iPSC-Derived Cardiomyocytes for Toxicity Testing and Phenotypic Drug Screening

Published on: March 31, 2022

Monitoring ER/SR Calcium Release with the Targeted Ca2+ Sensor CatchER+12:30

Monitoring ER/SR Calcium Release with the Targeted Ca2+ Sensor CatchER+

Published on: May 19, 2017

Related Concept Videos

Calmodulin-dependent Signaling01:16

Calmodulin-dependent Signaling

Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Ligand-Gated Ion Channel Receptor: Gating Mechanism01:30

Ligand-Gated Ion Channel Receptor: Gating Mechanism

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...
Feedback Regulation of Calcium Concentration01:27

Feedback Regulation of Calcium Concentration

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...
G-Protein Gated Ion Channels01:21

G-Protein Gated Ion Channels

GPCRs are primarily responsible for our sense of smell, taste, and vision.  The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Voltage-gated Ion Channels01:26

Voltage-gated Ion Channels

Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Ligand-gated Ion Channels01:19

Ligand-gated Ion Channels

Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...