Ankyrin-G and ankyrin-B ion channel/transporter complexes in the heart. (A) Ankyrin-G is required for the targeting of Na_v1.5 to the cardiomyocyte intercalated disc. Although other Na_v1.5-interacting proteins have been identified, it is not yet clear whether these are present in the ankyrin-G–dependent protein complex. (B) Ankyrin-B is required for the targeting of Na/Ca exchanger and Na/K ATPase to transverse tubule membranes in the heart. InsP₃ receptor targeting to the sarcoplasmic reticulum membrane requires direct interaction with ankyrin-B. Cardiac ankyrin-B protein partners also include PP2A and β2-spectrin.