Low-conductance high selective inositol (1,4,5)-trisphosphate activated Ca2+ channels in plasma membrane of A431 carcinoma cells.
In many cells, activation of receptors coupled to PIP2 turnover results in Ca2+ release from the intracellular stores accompanied by Ca2+ influx across the PM. It is not well established yet whether Ca2+ influx is activated by IP3 or by an unknown signal generated upon Ca2+ store depletion. We report here a single-channel study of low-conductance IP3-activated channels of very high selectivity for Ca2+ in the PM of A431 carcinoma cells. The channels are strongly potential dependent and sensitive to [Ca2+]i within the physiological range. The data obtained argues for IP3 acting directly on plasma membrane Ca2+ channels.
Kiselyov
K I
KI
Institute of Cytology, Russian Academy of Sciences, St. Petersburg.
Mamin
A G
AG
Semyonova
S B
SB
Mozhayeva
G N
GN
D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004553:Electric Conductivity; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; D015544:Inositol 1,4,5-Trisphosphate