Figure 3.

CREB signal strength is steeply dependent on channel P_o but not Ca²⁺ flux per se. (A) Log–log plot of signal strength versus Ca²⁺ flux for the [K⁺]_o indicated. Solid line shows the linear fit of the data. (B) Whole-cell Ca²⁺ flux (as in Fig. 2 D), in the presence of 0, 20, or 200 μM Cd²⁺. (C) CREB signal strength for 40 K⁺ with 0, 20, or 200 μM Cd²⁺ measured as described in Fig. 1 and Materials and methods; n = 3–6 experiments. The solid line is a linear fit of the Cd²⁺ data. For comparison, the dashed line and gray data points are reproduced from A. Error bars represent SEM.