Voltage-gated mobility of the Ca2+ channel cytoplasmic tails and its regulatory role.

Transient increase in intracellular free Ca(2+) concentration generated by the voltage-gated Ca(v)1.2 channels acts as an important intracellular signal. By using fluorescence resonance energy transfer combined with patch clamp in living cells, we present evidence for voltage-gated mobility of the cytoplasmic tails of the Ca(v)1.2 channel and for its regulatory role in intracellular signaling. Anchoring of the C-terminal tail to the plasma membrane caused an inhibition of its state-dependent mobility, channel inactivation, and CREB-dependent transcription. Release of the tail restored these functions suggesting a direct role for voltage-gated mobility of the C-terminal tail in Ca(2+) signaling.