Fig. 2

Schematic diagram of the structure of sarcoendoplasmic reticulum calcium ATPase (SERCA). The 3-dimensional crystal structure shows a SERCA pump in the ADP- and Ca²⁺-bound state. D351 (in red) is the residue phosphorylated during the movement of Ca²⁺ ions into the ER or SR. The three cytoplasmic domains, phosphorylation (P), nucleotide binding (N), and actuator (A) are labeled. ADP is shown in yellow and Ca²⁺ ions in green. Figure adapted from [69]