The Apicoplast: An Ancient Algal Endosymbiont of Apicomplexa

Abstract

The discovery of a chloroplast in the Apicomplexa came as a surprise as these are nonphotosynthetic parasites that historically had been the domain of zoologists. This organelle, the apicoplast is essential for parasite survival and its metabolism is intensively pursued as the source of new targets for antiparasitic drugs, in particular new antimalarials. The apicoplast has a remarkable evolutionary history, and this history is reflected in its complex structure and cell biology. A cyanobacterium and two eukaryotes have contributed to the genesis of this organelle and their contributions can still be traced today. This chapter sets out by briefly summarizing the studies that led to the discovery of the apicoplast fol- lowed by an overview of our most current knowledge of the molecular mech- anisms of apicoplast protein import, apicoplast division and replication and apicoplast metabolism.