[1] It is a Ca2+ ATPase that transfers Ca2+ from the cytosol of the cell to the lumen of the SR.[1] This uses energy from ATP hydrolysis during muscle relaxation.
In addition to its calcium-transporting functions, SERCA1 generates heat in brown adipose tissue and in skeletal muscles.
[4][5] The rate at which SERCA moves Ca2+ across the SR membrane can be controlled by the regulatory protein phospholamban (PLB/PLN).
SERCA function is upregulated in the skeletal muscle of rabbits[8] and in rodent myocardium[9][10] by thyroid hormones.
There are additional post-translational isoforms of both SERCA2 and SERCA3, which serve to introduce the possibility of cell-type-specific Ca2+-reuptake responses as well as increasing the overall complexity of the Ca2+ signaling mechanism.