Fig. 2.

Ca²⁺ dependence of Ca²⁺ transport activity. Calcium uptake activity was assessed in cardiac lysates. (A) Results obtained from WT, PLN KO, NF-SLN transgenic, and NF-SLN transgenic on a PLN KO background. (B) Calcium uptake data in PLN2x overexpressing transgenic lines, NF-SLN transgenics on the PLN2x background, I40A superinhibitory PLN transgenics, and NF-SLN transgenic mice crossed to the I40A PLN transgenics. (C) K_Ca (pCa) is the negative logarithm of the Ca²⁺ concentration required to attain the half-maximal Ca²⁺ uptake rate. Data are mean ± SEM. Symbols: ∗, P < 0.05 versus WT (+/+); ϕ, P < 0.05 versus PLN KO.