Mitosome 5308173 203545569 2008-04-05T16:35:57Z 86.26.85.179 A '''mitosome''' is an [[organelle]] found in some unicellular [[eukaryote|eukaryotic]] organisms. The mitosome has only recently been found and named,<ref name="Tovar99">Tovar, J. et al (1999). The mitosome, a novel organelle related to mitochondria in the amitochondrial parasite ''Entamoeba histolytica''. ''Molecular Microbiology'' '''32''', 1013–1021.</ref> and its function has not yet been well characterized. It was termed a crypton by another group but that name is not being used any more. The mitosome has been detected only in [[Anaerobic organism|anaerobic]] or [[microaerophilic]] organisms that do not have [[mitochondrion|mitochondria]]. These organisms do not have the capability of gaining energy from oxidative phosphorylation, which is normally performed by mitochondria. The mitosome was first described in ''[[Entamoeba histolytica]],'' an intestinal parasite of humans.<ref name="Tovar99" /><ref name="Bakatselou03">Bakatselou, C. et al. (2003). Analysis of genes of mitochondrial origin in the genus Entamoeba. ''J. Eukaryotic Microbiology'' '''50''', 210–214.</ref> Mitosomes have also been identified in several species of [[Microsporidia]]<ref name="Williams02">Williams, B.A. et al (2002). A mitochondrial remnant in the microsporidian ''Trachipleistophora hominis''. ''Nature'' '''418''':865-869.</ref><ref name="Goldberg04">Goldberg, A.V. et al (2008). Localization and functionality of microsporidian iron-sulphur cluster assembly proteins. ''NAture'' '''452''':624-628.</ref> and in ''[[Giardia lamblia|Giardia intestinalis]]''<ref name="Tovar05">Tovar, J. et al. (2003). Mitochondrial remnant organelles of ''Giardia'' function in iron-sulphur protein maturation. ''Nature'' 2003 '''426''':172-176.</ref>. Mitosomes are almost certainly derived from mitochondria. Like mitochondria, they have a double membrane and most proteins are delivered to them by a [[signal peptide|targeting sequence]] of amino acids.<ref name="Tovar99" /><ref name="Williams02" /><ref name="Goldberg04" /> The targeting sequence is similar to that used for mitochondria and true mitochondrial presequences will deliver proteins to mitosomes.<ref name="Tovar99" /> A number of proteins associated with mitosomes have been shown to be closely related to those of mitochondria<ref name="Bakatselou03" /> or [[hydrogenosome]]s (which are also degenerate mitochondria).<ref name="Dolezal06">Dolezal, P. et al (2005). ''Giardia'' mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting. ''PNAS'' '''102''':10924-10929.</ref> Unlike mitochondria, mitosomes do not have [[gene]]s within them. The genes for mitosomal components are contained in the nuclear genome.<ref name="Tovar99" /> An early report suggested the presence of DNA in this organelle,<ref name="Ghosh00">Ghosh, S. et al. (2000). The Entamoeba histolytica mitochondrion-derived organelle (crypton) contains double-stranded DNA and appears to be bound by a double membrane. ''Infectious Immunology'' '''68''', 4319–4322.</ref> but more recent research has shown this not to be the case.<ref name="Leon04">Leon-Avila, G. & Tovar, J. (2004). Mitosomes of Entamoeba histolytica are abundant mitochondrion-related remnant organelles that lack a detectable organellar genome. ''Microbiology'' '''150''', 1245–1250.</ref> ==References== <references/> [[Category:Organelles]] [[ca:Mitosoma]] [[es:Mitosoma]] [[fr:Mitosome]]