Overview
- Ramu, Y. et al. (2018) J. Gen. Physiol., 150, 969.
Alomone Labs SpTx-1 inhibits Kir6.2/SUR1 channels stably expressed in HEK-293 cells.A. The percent inhibition of KATP channels (comprising Kir6.2 + SUR1 subunits) stably expressed in HEK-293 cells, in the presence of different concentrations of SpTx-1 (#STS-670). The KATP channels were recorded using the whole cell patch clamp technique. An IC50 value of 23.6 nM was found for SpTx-1 in this experiment.
B. A representative cell recording showing the KATP (Kir6.2 + SUR1) currents (I in nA) under control conditions (without toxin) compared to conditions with different concentrations of SpTx-1.
SpTx-1 is a 54 amino acid peptidyl toxin originally isolated from the venom of the centipede, Scolopendra polymorpha. This toxin blocks the adenosine triphosphate (ATP)-sensitive K+ (KATP) channel with a Kd value of 15 nM, primarily by targeting of the pore-forming inwardly rectifying K+ channel (Kir) 6.2 subunit that is coexpressed with the regulatory sulfonylurea receptor 1 (SUR1)1.
The KATP channel is a hetero-octameric protein complex, consisting of four Kir6.x pore subunits and four regulatory ATP-binding cassette SURx subunits. The KATP channels are present in many different tissues such as skeletal muscle, smooth muscle, pancreatic β-cells, cardiomyocytes, and brain. Since these channels are responsible for linking cell metabolism and membrane potential, they are crucial for the regulation of different cellular pathways2. Kir6.x or SUR mutations result in KATP channelopathies, which reflect the physiological roles of these channels, including but not limited to insulin secretion, cardiac protection, neuroprotection, and blood flow regulation3,4.
SpTx-1 (#STS-800) is a highly pure, synthetic, and biologically active toxin.
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