What does hERG channel do?

hERG mediates cardiac repolarization In the central nervous system of mammals, two other ERG channel genes are expressed (ERG2 and ERG3)11, and here heteromultimeric channel complexes of all three subunits can be formed12.

Do potassium channels have activation and inactivation gates?

Potassium channels are presumed to have two allosterically coupled gates, the activation gate and the selectivity filter gate, that control channel opening, closing, and inactivation. An activation process, occurring at the selectivity filter, has been recently proposed for several potassium channels.

What is N type inactivation?

Inactivation of Kv1. 4 channels is complex, involving at least two distinct mechanisms: N- and C-type. N-type inactivation is the result of rapid block of the conducting pore by the lipophilic N-terminal region of the channel, after channel opening (11–13).

Where are hERG channels?

Abstract. The human ether-a-go-go related gene (hERG) encodes the pore-forming subunit of the rapid component of the delayed rectifier K(+) channel, Kv11. 1, which are expressed in the heart, various brain regions, smooth muscle cells, endocrine cells, and a wide range of tumor cell lines.

What are hERG channel blockers?

Introduction: The HERG channel is widely used for the assessment of proarrhythmic risk for new drugs. HERG channel blockers obstruct channel functions through various mechanisms, which usually show time dependence, voltage dependence, and state dependence.

What is hERG activity?

HERG channels are involved in cardiac action potential repolarization, and reduced function of hERG lengthens ventricular action potentials, prolongs the QT interval in an electrocardiogram, and increases the risk for potentially fatal ventricular arrhythmias.

Do voltage-gated potassium channels have an inactivation gate?

After activation, most voltage-gated K+ channels can pass into a stable nonconducting, or inactivated, state through a process termed inactivation. The process of inactivation, however, is extremely variable in many of its properties and, presumably, mechanisms.

What is sodium channel inactivation?

Voltage-gated sodium channels open (activate) when the membrane is depolarized and close on repolarization (deactivate) but also on continuing depolarization by a process termed inactivation, which leaves the channel refractory, i.e., unable to open again for a period of time.

Do potassium channels inactivate?

In almost all potassium channels and many other ion channels, inactivation starts spontaneously as a consequence of activation, manifested as a decrease in current until it reaches a plateau with minimal conductance (Hoshi et al., 1991) (Fig. 3a,b).

What is hERG liability?

Introduction. The inhibition of the human ether-a-go-go (hERG) ion channel may cause QT interval prolongation, which eventually can result in torsades de pointes (TdP) [1] and even death. Hence cardiotoxicity caused by the inhibition of hERG is a major liability within the drug development process.

What is hERG assay?

A hERG (human Ether-a-go-go Related Gene) assay is a laboratory technique that gauges the activity of the hERG channel protein. How does the hERG assay support cardiac studies? hERG activity manifests as the movement of potassium ions through a pore present in the hERG channel protein.

Does fast inactivation gating cause hERG rectification?

Fast inactivation gating relative to slow activation gating has been implicated as the cause of hERG rectification (Schönherr and Heinemann, 1996; Smith et al., 1996; Spector et al., 1996; Herzberg et al., 1998).

Does the EAG domain bind to the pore for hERG inactivation?

Like C-type inactivation in Shaker (Hoshi et al., 1991; López-Barneo et al., 1993), hERG inactivation is dependent on pore residues (Schönherr and Heinemann, 1996; Smith et al., 1996; Herzberg et al., 1998) and the S6 domain (Herzberg et al., 1998). But the short cap region of the eag domain does not appear to bind the pore (Wang et al., 2000).

What does hERG stand for?

Human ether-á-go-go (eag)-related gene (hERG) potassium channel kinetics are characterized by rapid inactivation upon depolarization, along with rapid recovery from inactivation and very slow closing (deactivation) upon repolarization.

What is the function of the hERG potassium channel?

the hERG potassium channel. HERG channels are involved in cardiac action potential repolarization, and reduced function of hERG lengthens ventricular action potentials, prolongs the QT interval in an electrocardiogram, and increases the risk for poten‑ tially fatal ventricular arrhythmias.