Plays a role in promoting mitochondrial enlargement in cone photoreceptor cells in a fusion-independent and ATP-dependent manner. Colocalized with tom20 in cone mitochondria. Uniformly distributed throughout all mitochondria in cone ellipsoids including mega-mitochondria. Expressed specifically in the inner segments of cone photoreceptor cells of the retina (at protein level). Morpholino knockdown of the protein display decreased eye size and formation of smaller mitochondria in cone ellipsoid photoreceptor cells.