Association of annexin V with mitochondria.

Annexin V is an intracellular protein recently shown to be localized to nucleoli and cytosol. In this study we show that cytosolic annexin V is associated with mitochondria. To assess the nature of the annexin V-mitochondrial interaction, an annexin V binding activity was partially purified from placental cytosol by annexin V-affinity chromatography. Five polypeptides in the eluate appeared to be associated with annexin V, with a predominant species of 27 kDa. Antibodies to the 27 kDa polypeptide recognised mitochondria but not nucleoli. We conclude that annexin V interacts with a 27 kDa mitochondrial polypeptide that is possibly part of a larger complex.