Connexins are transmembrane proteins.The best-known function of connexins is to form gap junction channels.Cardiomyocytes predominantly express connexin 43(Cx43).Recent studies show that Cx43 is not only present at the sarcolemma but is also detected in mitochondria of cardiomyocytes,at least in part in the inner mitochondrial membrane.Mitochondrial Cx43 plays a central role for triggering/mediating the cardioprotection by ischemic preconditioning(IPC),however the molecular mechanisms have not been elucidated in detail.The present article reviews the available evidence on the localization,the mechanism of transport,the phosphorylation status,the affecting factors and the physiological role of mitochondrial Cx43.These findings open a new field for investigating the previously unsuspected roles of Cx43 in mitochondria about their functions,regulation and molecular mechanisms involved in pathophysiology not only in myocardial ischaemia-reperfusion injury but also in other conditions in the cardiovascular system and beyond.
