We have developed a protocol for expressing ryanodine receptors (RyR), specifically the rabbit skeletal RyR isoform (rbRyR1) and human cardiac RyR isoform (hRyR2), that respond to known RyR modulators, with the goal of developing molecular tools for FRET-based structural readouts of RyRs. Both RyR1 and RyR2 are composed of four 565 kDa subunits and are the primary Ca2+ channels in the sarcoplasmic reticulum (SR) of skeletal and cardiac muscle, respectively. Triggered SR Ca2+ release is required for muscle contraction, but RyR dysregulation can result in SR Ca leak during rest, which is linked to several myopathies, diabetes, and neurological disorders.