Abstract
Mechanical stress activates TRPM7 channels expressed in HEK293T cells Numata, Tomohiro; Shimizu, Takahiro; Okada, Yasunobu (Dept. Cell Physiol., Natl. Inst. Physiol. Sci., Okazaki, Japan)Stretch-activated cation channels play an essential role in sensing and transducing external mechanical stresses in living cells. In the previous meeting we reported that TRPM7 channels endogenously expressed in human epithelial HeLa cells are activated by membrane stretch or osmotic cell swelling. However, it has not been known whether TRPM7 shows mechanosensitivity when heterologously expressed. HEK293T cells overexpressed with TRPM7 exhibited whole-cell currents typical of TRPM7, such as outward rectification, conductivity to Ca2+, and sensitivity to Mg2+ and ruthenium red. In addition, TRPM7 currents were augmented by following three kinds of mechanical stimuli: shear stress imposed by perfusion of extracellular solution, membrane stretch produced by patch membrane suction, cell swelling due to hypotonic stimulation. We thus conclude that the TRPM7 channel can be activated by mechanical stress in the heterologous expression system. [J Physiol Sci. 2006;56 Suppl:S153]
