[Effects of actin cytoskeleton rearrangements on channel activation by calcium entry into A431 cells].
Using patch clamp and ion-selective fluorescence dye techniques, we investigated the influence of actin cytoskeleton rearrangements on the activity of calcium entry channels in plasma membrane of human carcinoma A431 cells. It is shown that disruption of actin microfilaments by cytohalasin D has no significant effect on calcium release from the stores and its entry from the extracellular space. It also does not interfere with the activation of inositol 1,4,5-trisphosphate (IP3)-dependent high-selective low-conductance calcium channels Imin. The treatment of cells with calyculin A induces the formation of actin filament layer beneath plasma membrane and also inhibits Imin activation and calcium entry through the plasma membrane, though calcium efflux from the stores was nearly unchanged. Thus, it is concluded that calcium signalling in A431 cells can be modulated by actin cytoskeleton rearrangements, and may be well described in terms of "conformational coupling" model.
Institute of Cytology RAS, St. Petersburg.
V A
VA
Alekseenko
K O
KO
Gusev
E V
EV
Kaznacheeva
D000199:Actins / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002120:Calcium Channel Agonists / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D020013:Calcium Signaling; D002294:Carcinoma, Squamous Cell / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology*; D004553:Electric Conductivity; D005110:Extracellular Space / Q000378:metabolism; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D015640:Ion Channel Gating; D008387:Marine Toxins; D010080:Oxazoles / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D019284:Thapsigargin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000199:Actins; D002120:Calcium Channel Agonists; D015220:Calcium Channels; D008387:Marine Toxins; D010080:Oxazoles; D015638:Cytochalasin D; D019284:Thapsigargin; C059041:calyculin A; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium