FKBP1A and catecholaminergic polymorphic ventricular tachycardia: In recent studies, S107, the RyR-specific derivative of JTV519, enhanced binding of FKBP12.6 to catecholaminergic polymorphic ventricular tachycardia (CPVT)-linked RyR2-R2474S mutant [26], and FKBP12 to the oxidized and hypernitrosylated RyR1 [20], [27], [28].