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Hydrocinnamic Acid Inhibits the Currents of WT and SQT3 Syndrome-Related Mutants of Kir2.1 Channel

Shuxi Ren, Chunli Pang, Yayue Huang, Chengfen Xing, Yong Zhan, Hailong An

J Membr Biol. 2017 Oct;250(5):425-432.

PMID: 28660286

Abstract:

Gain of function in mutations, D172N and E299V, of Kir2.1 will induce type III short QT syndrome. In our previous work, we had identified that a mixture of traditional Chinese medicine, styrax, is a blocker of Kir2.1. Here, we determined a monomer, hydrocinnamic acid (HA), as the effective component from 18 compounds of styrax. Our data show that HA can inhibit the currents of Kir2.1 channel in both excised inside-out and whole-cell patch with the IC50 of 5.21 ± 1.02 and 10.08 ± 0.46 mM, respectively. The time course of HA blockage and washout are 2.3 ± 0.6 and 10.5 ± 2.6 s in the excised inside-out patch. Moreover, HA can also abolish the currents of D172N and E299V with the IC50 of 6.66 ± 0.57 and 5.81 ± 1.10 mM for D172N and E299V, respectively. Molecular docking results determine that HA binds with Kir2.1 at K182, K185, and K188, which are phosphatidylinositol 4,5-bisphosphate (PIP2) binding residues. Our results indicate that HA competes with PIP2 to bind with Kir2.1 and inhibits the currents.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP501520 Hydrocinnamic acid Hydrocinnamic acid 501-52-0 Price
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