Apicoplast

Apicoplast is a unique organelle found in Apicomplexa, a group of parasitic protozoa. The apicoplast is a non-photosynthetic plastid that is vital for the survival of the parasite. It is involved in the synthesis of lipids, heme, and isoprenoids, which are essential components of the parasite's metabolism.

Origin

The apicoplast is believed to have originated from a secondary endosymbiosis event, where an ancestral apicomplexan engulfed a red algal cell. This is supported by the presence of four membranes surrounding the apicoplast, which is characteristic of secondary endosymbiosis.

Structure

The apicoplast is surrounded by four membranes, reflecting its complex evolutionary history. The two innermost membranes are thought to be remnants of the original algal plastid, while the two outer membranes are derived from the endomembrane system of the host cell.

Function

The apicoplast is involved in several essential metabolic pathways, including the synthesis of fatty acids, isoprenoids, and heme. These compounds are vital for the survival and virulence of the parasite. The apicoplast also contains its own genome, which encodes for proteins involved in these metabolic pathways.

Role in disease

Apicomplexan parasites, including those that cause malaria and toxoplasmosis, rely on the apicoplast for survival. Therefore, the apicoplast is a promising target for the development of new antiparasitic drugs. Several drugs that target the apicoplast, such as doxycycline and clindamycin, are currently in use or under investigation.

See also

• Plastid
• Endosymbiosis
• Apicomplexa