How do cells establish a functional nuclear-mitochondrial communication?

How do cells establish a functional nuclear-mitochondrial communication? What is the significance of the communication in physiological and pathological processes?

Although mitochondria have their own DNA, more than 98% of the total protein complement of the organelle is encoded by the nuclear genome. Mitochondrial biogenesis requires a coordination of expression of two genomes and therefore cross talk between the nucleus and mitochondria.