PROSITE documentation PDOC00675

Calsequestrin signatures

Calsequestrin is a moderate-affinity, high-capacity calcium-binding protein of cardiac and skeletal muscle [1], where it is located in the lumenal space of the sarcoplasmic reticulum terminal cisternae. Calsequestrin acts as a calcium buffer and plays an important role in the muscle excitation-contraction coupling. It is a highly acidic protein of about 400 amino acid residues that binds more than 40 moles of calcium per mole of protein. There are at least two different forms of calsequestrin: one which is expressed in cardiac muscles and another in skeletal muscles. Both forms have highly similar sequences.

We have developed two signature sequences, the first one corresponds to the N-terminus of the mature protein; the second is located just in front of the C-terminus of the protein which is composed of a highly acidic tail of variable length.