Survivin can alter mitochondrial architecture by regulating phosphatidylethanolamine synthesis.

Survivin (encoded by BIRC5) is an essential protein with established roles in mitosis and the inhibition of apoptosis. It is overexpressed in cancers, its abundance correlating with resistance to radiotherapies and chemotherapies. Survivin expression is normally limited to G2 and M phases; however, in cancer cells, it is also present during interphase and gains access to the mitochondria. Phosphatidylethanolamine (PE) is a phospholipid that facilitates negative curvature of membranes. It is enriched in the cytokinetic furrow and mitochondria, where it enables tight packing of the cristae and the increased accommodation of proteins. Here, we report the remarkable discovery that mitochondrial survivin regulates phosphatidylserine decarboxylase activity, thereby affecting PE availability. This novel molecular insight suggests that some apparently disparate roles of this 'multitasking' protein might be fundamentally linked to membrane architecture, and offers a new perspective on its contribution to cancer and potentially other metabolic disorders.