Cardiac mitochondria: a surprise about size

Abstract

Mitochondria dynamics are regulated by cycles of fusion and fission. Increasingly, evidence suggests that alterations in mitochondrial size and appearance may be linked to cardiac dysfunction and disease. Now, a new report suggests that those proteins involved in regulating the fusion of cardiac mitochondria may have functions that extend beyond mitochondrial dynamics and that the size of cardiac mitochondria may not be as informative as previously believed.

Figure 1

The relationship between mitochondrial size and function is less clear than once believed. Manipulation of the genes involved in fission (Drp1) or fusion (MARF and Opa1) can produce similar alterations in mitochondrial size but very different effects on the function of Drosophila hearts. Similarly, knockdown of MARF and Opa1 produce a similar inhibition of mitochondrial fusion and result in a cardiomyopathy, however these functional defects are rescued by non-overlapping genetic strategies.