Mitochondria: Getting together

摘要

Mitochondria are enjoying something of a renaissance in terms of their importance in regulating tumour cell function. Mitochondria are dynamic structures that undergo both fusion and fission under a variety of conditions, which according to a paper published in Genes and Development now includes activation of the Hippo pathway in Drosophila melanogaster and mammalian cells.Deregulation of the Hippo pathway has been implicated in tumour development, and given its importance in regulating cell size and tissue growth, Raghavendra Nagaraj, Shubha Gururaja-Rao and colleagues investigated whether this pathway also impinges on mitochondrial regulation. They looked at cells in D. melanogaster that overexpressed Yorkie (YKI), a transcriptional co-activator downstream of the kinase Hippo, and found the number and size of the mitochondria significantly increased. Mutations in components of the Hippo pathway that result in the activation of this pathway had a similar effect, but overexpression of the microRNA bantam, a transcriptional target of YKI that is known to result in tissue overgrowth, had no effect on mitochondria. Indeed, overexpression of YKI in post-mitotic cells indicated that the effect of YKI on mitochondria was not linked to cell proliferation.