The Evolution and Function of Co-Chaperones in Mitochondria - The Networking of Chaperones by Co-chaperones - page 199

Chapter 10
The Evolution and Function of Co-Chaperones
in Mitochondria

Neta Regev-Rudzki, Kip Gabriel and Dejan Bursać

Abstract Mitochondrial chaperones mediate and affect critical organellar pro-
cesses, essential for cellular function. These chaperone systems have both pro-
karyotic and eukaryotic features. While some of the mitochondrial co-chaperones
have clear homologues in prokaryotes, some are unique to eukaryotes and have
no homologues in the chaperone machinery of other cellular compartments. The
mitochondrial co-chaperones are required for protein import into the organelle and
in enforcing the structure of the main chaperones. In addition to novel types of
interaction with their senior partners, unexpected and essential interactions between
the co-chaperones themselves have recently been described.

Keywords Co-chaperones ﾷ Mitochondria ﾷ Protein translocation ﾷ Evolution

Introduction

The mitochondrion is an endosymbiotically derived double membrane organelle
of prokaryotic origin, characteristic of eukaryotic organisms. The organelle still
retains many prokaryotic features, such as 70S ribosomes, the machinery to syn-
thesize FeS clusters and its own circular chromosomal DNA. The mitochondrion is
enveloped by two membranes, the outer and the inner membrane. All mitochondrial
co-chaperones identified to date are localized in the lumen of the inner membrane,
the mitochondrial matrix. While comparative analyses of mitochondrial chaperones