TY - JOUR
T1 - Protein import, replication, and inheritance of a vestigial mitochondrion
AU - Regoes, Attila
AU - Zourmpanou, Danai
AU - León-Avila, Gloria
AU - Van Der Giezen, Mark
AU - Tovar, Jorge
AU - Hehl, Adrian B.
PY - 2005/8/26
Y1 - 2005/8/26
N2 - Mitochondrial remnant organelles (mitosomes) that exist in a range of "amitochondrial" eukaryotic organisms represent ideal models for the study of mitochondrial evolution and for the establishment of the minimal set of proteins required for the biogenesis of an endosymbiosis-derived organelle. Giardia intestinalis, often described as the earliest branching eukaryote, contains double membrane-bounded structures involved in iron-sulfur cluster biosynthesis, an essential function of mitochondria. Here we present evidence that Giardia mitosomes also harbor Cpn60, mtHsp70, and ferredoxin and that despite their advanced state of reductive evolution they have retained vestiges of presequence-dependent and -independent protein import pathways akin to those that operate in mammalian mitochondria. Although import of IscU and ferredoxin is still reliant on their amino-terminal presequences, targeting of Giardia Cpn60, IscS, or mtHsp70 into mitosomes no longer requires cleavable presequences, a derived feature from their mitochondrial homologues. In addition, we found that division and segregation of a single centrally positioned mitosome tightly associated with the microtubular cytoskeleton is coordinated with the cell cycle, whereas peripherally located mitosomes are inherited into daughter cells stochastically.
AB - Mitochondrial remnant organelles (mitosomes) that exist in a range of "amitochondrial" eukaryotic organisms represent ideal models for the study of mitochondrial evolution and for the establishment of the minimal set of proteins required for the biogenesis of an endosymbiosis-derived organelle. Giardia intestinalis, often described as the earliest branching eukaryote, contains double membrane-bounded structures involved in iron-sulfur cluster biosynthesis, an essential function of mitochondria. Here we present evidence that Giardia mitosomes also harbor Cpn60, mtHsp70, and ferredoxin and that despite their advanced state of reductive evolution they have retained vestiges of presequence-dependent and -independent protein import pathways akin to those that operate in mammalian mitochondria. Although import of IscU and ferredoxin is still reliant on their amino-terminal presequences, targeting of Giardia Cpn60, IscS, or mtHsp70 into mitosomes no longer requires cleavable presequences, a derived feature from their mitochondrial homologues. In addition, we found that division and segregation of a single centrally positioned mitosome tightly associated with the microtubular cytoskeleton is coordinated with the cell cycle, whereas peripherally located mitosomes are inherited into daughter cells stochastically.
UR - http://www.scopus.com/inward/record.url?scp=24044432249&partnerID=8YFLogxK
U2 - 10.1074/jbc.M500787200
DO - 10.1074/jbc.M500787200
M3 - Artículo
C2 - 15985435
AN - SCOPUS:24044432249
SN - 0021-9258
VL - 280
SP - 30557
EP - 30563
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 34
ER -