8.A.88 The Calciquestrin (CAQS) Family
Calsequestrin is a high-capacity, moderate affinity, calcium-binding protein that acts as an internal calcium store in muscle. Calcium ions are bound by clusters of acidic residues at the protein surface, often at the interface between subunits. The protein can bind around 80 Ca2+ ions. It regulates the release of lumenal Ca2+ via the calcium release channel RYR1 which plays an important role in triggering muscle contraction (Sanchez et al. 2012).