Junctophilin-2 (JPH2) is a cardiac specific member of the junctophilins, a newly characterized family of junctional membrane complex proteins important in physically approximating the plasmalemmal L-type calcium channel and the sarcoplasmic reticulum ryanodine receptor for calcium-induced calcium release. It acts probably by anchoring the plasma membrane and endoplasmic reticulum. JPH2 contributes to the construction of skeletal muscle triad junctions, and plays an essential role in heart development.