![Figure 5. Slope conductance of an InsP3R-3 channel at Vrev in symmetric 140-mM KCl solutions with various divalent cation concentrations. SEM for all data points are shown as error bars, some of which are smaller than the size of the symbols. The number of measurements performed for each ionic condition is tabulated next to the corresponding data point in the same color. The same symbols in the same color are used for the same set of data points plotted in the different graphs. (A) gch versus [Ca2+]ER in the presence of various symmetric [Mg2+]f as tabulated. Curves are fits to gch data by the empirical inhibition equation (Eq. 2), with different KCaER for various [Mg2+]f. The red curve is for gch in 0 [Mg2+]f. (B) gch versus concentrations of divalent cations in the cytoplasmic or luminal side of the channel as tabulated. The purple curve is described by Eq. 3, and the red one is described by Eq. 2. (C) gch versus equivalent divalent cation concentrations [X2+]eq = [Ca2+]ER + 0.5 × ([Mg2+]i + [Mg2+]ER) for various combinations of [Ca2+]ER, [Mg2+]ER, and [Mg2+]i as tabulated. The red curve is described by Eq. 5.](https://cdn.rupress.org/rup/content_public/journal/jgp/136/6/10.1085_jgp.201010513/5/jgp_201010513_rgb_fig5.jpeg?Expires=1773496781&Signature=GIB0YvelvN37cxwiQssO2IuvbtZEKtS1Rxb~BRGIWT4uQ4RsfzJRwQjrdqFFlfppFqYwrv3gJRuyEVS2mv4u64mt22OTKaQWsihmFw1wK0ReKVBkBabbxuUMFs9Jb01rCaD1SCE3tz4ZqEYGgHHVw14dbGjq7yE6~uAQhT0KLorXjNK2AsMFg4WH7AYt7vkCqamYPpCvC~OL~k79xA-ji2ZXiq2Jnw2wLBeu1npM3~snb-cC~BKoyqBSSZS5SZaxZmIKjgEERxi3alJuAeF2uXmx3Ue6wQlXnzA-JY25iHuskXeAHdF7U485Zt0q00Esp-wbposfRaO9Ylseq6M49g__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Slope conductance of an InsP3R-3 channel at Vrev in symmetric 140-mM KCl solutions with various divalent cation concentrations. SEM for all data points are shown as error bars, some of which are smaller than the size of the symbols. The number of measurements performed for each ionic condition is tabulated next to the corresponding data point in the same color. The same symbols in the same color are used for the same set of data points plotted in the different graphs. (A) gch versus [Ca2+]ER in the presence of various symmetric [Mg2+]f as tabulated. Curves are fits to gch data by the empirical inhibition equation (Eq. 2), with different KCaER for various [Mg2+]f. The red curve is for gch in 0 [Mg2+]f. (B) gch versus concentrations of divalent cations in the cytoplasmic or luminal side of the channel as tabulated. The purple curve is described by Eq. 3, and the red one is described by Eq. 2. (C) gch versus equivalent divalent cation concentrations [X2+]eq = [Ca2+]ER + 0.5 × ([Mg2+]i + [Mg2+]ER) for various combinations of [Ca2+]ER, [Mg2+]ER, and [Mg2+]i as tabulated. The red curve is described by Eq. 5.
