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Opening of ligand‐gated cation channel families by calpain inhibitors 1
Author(s) -
Suzuki Makoto,
Ohki Gaku,
Mochizuki Toshio,
Somlo Stefan,
Ishibashi Kenichi,
Imai Masashi
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)02627-3
Subject(s) - chinese hamster ovary cell , transient receptor potential channel , calpain , trpc1 , chemistry , ion channel , receptor , transmembrane protein , biophysics , microbiology and biotechnology , channel blocker , western blot , trpv , patch clamp , biology , biochemistry , calcium , trpv1 , organic chemistry , gene , enzyme
The class of Ca 2+ ‐permeable cation channels is composed of large families with six transmembrane segments including transient receptor potential, vanilloid receptor (VR), polycystin, epithelial calcium channels and melastatin (MLS). However, most of them are functionally silent and unexpressed in mammalian cells. An investigation of associated proteins made us believe that the blockade of calpain opens the silent channels. Using 1 μM of blockers in whole cellular patch pipette fill we measured currents of Chinese hamster ovary cells transfected by VR‐like 1 and 2, polycystin‐2, or a MLS‐like new member (MLS3S). Significant conductance of every clone with a characteristic rectification by blockers was demonstrated. The permeability of Ca 2+ to them is similar to that reported. Western blot suggested that blockers did not affect the assembly of the protein but enabled its cleavage. Therefore, investigation of these families with the blockers may boost our knowledge of electrophysiologic function.