Mitochondria breathe for autophagy

Proper mitochondrial structure and function are established by continuous cycles of fusion and fission, and a unidirectional pathway of autophagy-mediated degradation. In this issue of The EMBO Journal, Graef and Nunnari (2011) demonstrate that autophagy requires healthy mitochondria in cells under amino-acid starvation. Defects in mitochondrial respiration cause activation of cAMP-dependent protein kinase A (PKA), an evolutionarily conserved regulator that inhibits autophagic flux. This study reveals a crucial interplay between mitochondrial function and autophagy, and raises the possibility that deregulation in one of these processes simultaneously compromises the other to potentiate risks for various human disorders.