Title

2-Aminoethyl Diphenyl Borinate (2-APB) Inhibits TRPM7 Channels Through an Intracellular Acidification Mechanism

Document Type

Article

Publication Date

8-24-2012

Abstract

2-APB is a widely used compound in ion channel research. It affects numerous channels including inositol 1,4,5-trisphosphate receptors, store-operated calcium channels and TRP channels, TRPV3 and TRPM7 among them. A characteristic property of TRPM7 channels is their sensitivity to intracellular Mg2+ and pH. Using patch clamp electrophysiology we find that in Jurkat T lymphocytes, 100–300 µM extracellular 2-APB reversibly inhibits TRPM7 channels when internal HEPES concentration is low (1 mM). Increasing the concentration to 140 mM abolishes the 2-APB effect. Using single-cell fluorescence pH video imaging, we show that at concentrations of 100 µM and higher, 2-APB potently acidifies the cytoplasm. We conclude that TRPM7 sensitivity to 2-APB is not direct but rather, can be explained by cytoplasmic acidification and a resulting channel inhibition.

DOI

10.4161/chan.21628

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