Shaping mitochondrial dynamics: The role of cAMP signalling

In recent years, our idea of mitochondria evolved from "mere" energy and metabolite producers to key regulators of many cellular functions. In order to preserve and protect their functional status, these organelles engage a number of dynamic processes that allow them to decrease accumulated burden and maintain their homeostasis. Indeed, mitochondria can unite (fusion), divide (fission), position themselves strategically in the cell (motility/trafficking) and if irreversibly damaged or dysfunctional eliminated (mitophagy). These dynamic processes can be controlled both by mitochondrial and cellular signalling pathways, hence allowing mitochondria to tune their function to the cellular needs. Among the regulatory mechanisms, reversible phosphorylation downstream the cyclic AMP (cAMP) signalling cascade was shown to deeply influence mitochondrial dynamics. This review explores the emerging evidence suggesting that cAMP is a key player in the orchestration of mitochondrial fusion/fission, motility and mitophagy, extending the repertoire of this second messenger, which is now recognised as a major regulator of mitochondrial homeostasis.