Cloning and functional expression of a human Ca2+-permeable cation channel activated by calcium store depletion.
Depletion of intracellular calcium stores generates a signal that activates Ca2+-permeable channels in the plasma membrane. We have identified a human cDNA, TRPC1A, from a human fetal brain cDNA library. TRPC1A is homologous to the cation channels trp and trpl in Drosophila and is a splice variant of the recently identified cDNA Htrp-1. Expression of TRPC1A in CHO cells induced nonselective cation currents with similar permeabilities for Na+, Ca2+, and Cs+. The currents were activated by intracellular infusion of myo inositol 1,4,5-trisphosphate or thapsigargin. Expression of TRPC1A significantly enhanced increases in the intracellular free calcium concentration induced by Ca2+ restitution after prolonged depletion. Similar results were obtained in Sf9 cells. We conclude that TRPC1A encodes a Ca2+-permeable cation channel activated by depletion of intracellular calcium stores.
Zitt
C
C
Institut für Pharmakologie, Freie Universität Berlin, Federal Republic of Germany.
Zobel
A
A
Obukhov
A G
AG
Harteneck
C
C
Kalkbrenner
F
F
Lückhoff
A
A
Schultz
G
G
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D015220:Calcium Channels / Q000235:genetics / Q000502:physiology*; D002412:Cations; D003001:Cloning, Molecular; D006224:Cricetinae; D006801:Humans; D007473:Ion Channels / Q000235:genetics / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D008969:Molecular Sequence Data; D018408:Patch-Clamp Techniques
D015220:Calcium Channels; D002412:Cations; D007473:Ion Channels