| Type: | Conserved_site | Name: | Calsequestrin, conserved site |
| Description: | Calsequestrin is the principal calcium-binding protein present in the sarcoplasmic reticulum of cardiac and skeletal muscle []. It is a highly acidic protein that is able to bind over 40 calcium ions and acts as an internal calcium store in muscle. Sequence analysis has suggested that calcium isnot bound in distinct pockets via EF-hand motifs, but rather via presentation of a charged protein surface. Two forms of calsequestrin have been identified. The cardiac form is present in cardiac and slowskeletal muscle and the fast skeletal form is found in fast skeletal muscle. The release of calsequestrin-bound calcium (through a a calciumrelease channel) triggers muscle contraction. The active protein is not highly structured, more than 50% ofit adopting a random coil conformation []. When calcium binds there is a structural change wherebythe alpha-helical content of the protein increases from 3 to 11% [].Both forms of calsequestrin are phosphorylated by casein kinase II, but the cardiac form is phosphorylated more rapidly and to a higher degree []. | Short Name: | Calsequestrin_CS |
