What is the process of mitochondrial fusion?

The steps of mitochondrial fusion are described below.

1. Initiation: Fusion begins with the recognition and docking of two adjacent mitochondria in close proximity to each other. The outer membranes of the two mitochondria fuse together, facilitated by proteins called mitofusins (MFN1 and MFN2).
2. Membrane Approach and Deformation: Once the mitochondria are aligned, the outer membranes begin to approach each other and undergo deformation.
3. Membrane Destabilization and Merging: As the outer membranes continue to approach each other, they become destabilized, leading to the merging of their lipid bilayers. This merging process involves the fusion of the outer leaflets of the lipid bilayers, resulting in the formation of a hemifused structure.
4. Formation and Growth of Fusion Pore: The final stage of mitochondrial fusion involves the formation and growth of a fusion pore between the two mitochondria; this pore allows for the mixing of the contents of the two aqueous compartments. 
5. Complete Fusion: The two individual mitochondria merge to form a single, elongated organelle with a shared internal matrix and interconnected inner and outer membranes.