Lack of functional assembly in mitochondrial supercomplexes: a new insight into impaired mitochondrial function?

A new mitochondrial disorder in heart failure that fits in the category of mitochondrial cytopathies is the exciting finding in the paper by Rosca et al. 1 presented in this issue of Cardiovascular Research , which also explores a new insight into the functionality of mitochondria in the heart. The function of heart muscle is highly dependent on the energy generated by mitochondria by oxidation of fatty acids and carbohydrates through the tricarboxylic acid cycle, which is the direct source of electrons for the respiratory electron chain where oxidative phosphorylation and associated ATP synthesis takes place. Defects in mitochondrial structure and function have been found in association with cardiovascular diseases such as dilated and hypertrophic cardiomyopathy, cardiac conduction defects and sudden death, ischaemic and alcoholic cardiomyopathy, as well as myocarditis. While a subset of these mitochondrial abnormalities has a defined genetic basis, other abnormalities appear to be due to a more sporadic or environmental cardiotoxic insult or have not yet been characterized.2,3 A major function of mitochondria is the conversion of energy released by metabolic processes in the mitochondrial matrix into the energy currency of the cell—ATP—a process mediated by the oxidative phosphorylation system (OXPHOS), a group of transmembrane protein complexes which constitute the … *Corresponding author. Tel: + 34 971 173 187; fax: + 34 971 173 184. E-mail address : paco.garcia-palmer{at}uib.es