SERCA

SERCA (abbr. for Sarcoplasmic / endoplasmic reticulum calcium ATPase pump of sarcoplasmic calcium German and endoplasmic reticulum ) are called proteins in the membrane of certain cell components, pump the calcium ions from the outside to the inside. They belong to the calcium channels and occur in all chordates. Three genes encode for ten SERCA isoforms in humans, where isoforms 1A and 2A only occur in the muscles, where it can represent up to 90 percent of the protein. Mutations in the genes can lead to diseases such as Brody 's disease, Acrokeratosis veruciformis (Crohn Hopf ) and Darier's disease. Incorrect reading of ATP2A1 due to mutations in the gene DMPK kinase results in a defective isoform SERCA1, which in turn is the cause of myotonic dystrophy type 1.

Function

To coordinate the trillions myosin motors in muscle movement of calcium ions are distributed. The contraction ceases only when the calcium is pumped back into the sarcoplasmic back / ER. For this purpose, SERCA transporters are installed in the membrane of these compartments. But also in other tissues, calcium is used as a messenger, just not as concentrated as in muscles.

The transport equation is:

ATP H2O H ( sr / s) Ca2 ( cyt ) ⇒ ADP phosphate Ca2 ( sr / s) H ( cyt )

It is a Ca2 : H antiport.

Outside the calcium transport seems SERCA1 in particular adipocytes to generate heat. The amount of heat generated in the muscle can be measured.

Regulation

Expression of SERCA1 in certain muscle cells in rabbits is dependent on thyroid hormones.