Figure 1.

CaT-L. shows Ca²⁺-dependent inactivation and binds calmodulin. (A) Representative current recorded during a voltage step to −100 mV. At least two inactivation time constants can be distinguished in 30 mM [Ca²⁺]_o. (B) Current recorded in 30 mM [Ba²⁺]_o. Note that activation is delayed, the initial fast inactivation component is missing, and currents only show a very slow second component of inactivation. (C) ³⁵S-labeled CaT-L binds to CaM-agarose in the presence, but not absence of Ca²⁺ (Left). GST-fusion proteins of CaT-L were constructed according to the schematic drawing (Right). aa, amino acid residues. (D) Binding of [³⁵S]CaM to different CaT-L GST-fusion proteins in the presence (+) or absence of calcium.