OTRPC4, a nonselective cation channel that confers sensitivity to extracellular osmolarity.
Ca2+-permeable channels that are involved in the responses of mammalian cells to changes in extracellular osmolarity have not been characterized at the molecular level. Here we identify a new TRP (transient receptor potential)-like channel protein, OTRPC4, that is expressed at high levels in the kidney, liver and heart. OTRPC4 forms Ca2+-permeable, nonselective cation channels that exhibit spontaneous activity in isotonic media and are rapidly activated by decreases in, and are inhibited by increases in, extracellular osmolarity. Changes in osmolarity of as little as 10% result in significant changes in intracellular Ca2+ concentration. We propose that OTRPC4 is a candidate for a molecular sensor that confers osmosensitivity on mammalian cells.
Strotmann
R
R
Institut für Pharmakologie, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Thielallee 67-73, 14195 Berlin, Germany.
Harteneck
C
C
Nunnenmacher
K
K
Schultz
G
G
Plant
T D
TD
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D027682:Cation Transport Proteins; D002412:Cations / Q000378:metabolism*; D004553:Electric Conductivity; D004594:Electrophysiology; D007473:Ion Channels / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007668:Kidney / Q000737:chemistry; D008099:Liver / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D009206:Myocardium / Q000737:chemistry; D009997:Osmotic Pressure; D018408:Patch-Clamp Techniques; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D050916:TRPV Cation Channels; D014018:Tissue Distribution
D027682:Cation Transport Proteins; D002412:Cations; D007473:Ion Channels; D050916:TRPV Cation Channels; C486576:Trpv4 protein, mouse; D002118:Calcium