Opa1 is a dynamin-like guanosine triphosphatase required for mitochondrial fusion and regulation of apoptosis. Its activity is controlled by proteolytic cleavage. Stress conditions that cause loss of mitochondrial membrane potential can induce the cleavage of Opa1 at S1 position by OMA1 (an ATP-independent peptidase), and this triggers mitochondrial fragmentation []. It is also involved in mitochondrial cristae remodeling during apoptosis [].
This entry represents the C-terminal domain of Dynamin-like GTPase OPA1. This protein is involved in mitochondrial fusion and inner membrane remodelling, essential for normal mitochondrial morphology by regulating the equilibrium between mitochondrial fusion and mitochondrial fission [, , ]. Mutations in human OPA1 cause optic atrophy []. This domain includes the helix bundle (HB) domains HB1 (at the extreme C-terminal) and HB2 (equivalent to bundle signaling element (BSE) and to the stalk domain of dynamin-1, respectively) that associate with the N-terminal G domain and the lipid-interacting stalk (LIS, equivalent to the PH domain of dynamin-1) [].
