Yes, there are two main isoforms of calsequestrin: calsequestrin-1 and calsequestrin-2. Calsequestrin-1 is primarily found in skeletal muscle, while calsequestrin-2 is found in cardiac muscle. Both isoforms share similar functions but are adapted to the specific physiological needs of their respective muscle types. For example, the rapid and sustained contractions of cardiac muscle require a different calcium handling mechanism compared to skeletal muscle.
