Catrin-2 weakly blocks contraction of smooth muscle elicited by high potassium-induced depolarization, but does not block caffeine-stimulated contraction. Catrin-1 has no significant effect. May target voltage-gated calcium channels on smooth muscle. Expressed by the venom gland. Catrin-1. Catrin-2. Belongs to the CRISP family. Some authors describe two catrins (catrin-1 and -2), with different activities and masses, but no difference in sequence is described.