Calsequestrin-1 (CASQ1)

Calsequestrin is a high-capacity, moderate affinity, calcium-binding protein and so acts as an internal calcium store in muscle (PubMed:28895244). Calcium ions are bound by clusters of acidic residues in the protein surface, often at the interface between subunits.

Can bind around 80 Ca(2+) ions (PubMed:28895244). Regulates the discharge of lumenal Ca(2+) through the calcium release channel RYR1; this plays an significant role in triggering muscle contraction.