Mitosome

A mitosome (also called a crypton in early literature) is a mitochondrion-related organelle (MRO) found in a variety of parasitic unicellular eukaryotes, such as members of the supergroup Excavata. The mitosome was first discovered in 1999 in Entamoeba histolytica, an intestinal parasite of humans, and mitosomes have also been identified in several species of Microsporidia and in Giardia intestinalis.

The mitosome has been detected only in anaerobic or microaerophilic eukaryotes which do not have fully developed mitochondria, and hence do not have the capability of gaining energy from mitochondrial oxidative phosphorylation. The functions of mitosomes, while varied, have not yet been well characterized, but they may be associated with sulfate metabolism and biosynthesis of phospholipids and Fe–S clusters. Mitosomes, like other MROs, likely evolved from mitochondria, based on similarities in structure, function, and biochemical signaling pathways, and may have convergently evolved across eukaryote lineages.