IC50: 2.8?μM (mPTP)

ER-000444793 is a small molecule, non-toxic mPTP inhibitor with a mechanism of action independent of CypD inhibition. ER-000444793 potently and dose-dependently inhibits Ca ²⁺ -induced mPT. ER-000444793 binds CypD, a CsA/CypD homogenous time-resolved fluorescence (HTRF) assay is used to study compound binding. Both CsA and SfA dose-dependently decrease HTRF signal, suggesting displacement of labelled CsA from rhCypD protein (CsA IC ₅₀ =23?nM and SfA IC ₅₀ =?5?nM). In contrast, ER-000444793 has no effect up to a concentration of 50?μM, indicating lack of displacement of labelled-CsA from rhCypD protein. Together, these data suggest the mechanism of ER-000444793 in delaying mPT is independent of CypD functional inhibition.