Cloning of a stretch-inhibitable nonselective cation channel.
A homologue of the capsaicin receptor-nonselective cation channel was cloned from the rat kidney to investigate a mechanosensitive channel. We found this channel to be inactivated by membrane stretch and have designated it stretch-inactivated channel (SIC). SIC encodes a 563-amino acid protein with putative six transmembrane segments. The cDNA was expressed in mammalian cells, and electophysiological studies were performed. SIC-induced large cation currents were found to be regulated by cell volume, with currents being stimulated by cell shrinkage and inhibited by cell swelling. Single channel analysis showed a conductance of 250 pS with cation permeability (PCl/PNa < 0.1), and the channel possessed some of the characteristics of a stretch-inactivated channel in that it was permeable to calcium, sensitive to membrane stretch, and blocked by Gd3+. Therefore, we cloned one of the mechanosensitive cation channels of mammals, which is considered to regulate Ca2+ influx in response to mechanical stress on the cell membrane.
Department of Pharmacology, Jichi Medical School, Minamikawachi, Tochigi 329-04, Japan. macsuz@jichi.ac.jp
M
M
Suzuki
J
J
Sato
K
K
Kutsuwada
G
G
Ooki
M
M
Imai
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D015640:Ion Channel Gating; D007473:Ion Channels / Q000235:genetics*; D007668:Kidney / Q000378:metabolism*; D008969:Molecular Sequence Data; D009928:Organ Specificity; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011955:Receptors, Drug / Q000235:genetics*; D013314:Stress, Mechanical
D018076:DNA, Complementary; D007473:Ion Channels; D012333:RNA, Messenger; D011955:Receptors, Drug