1,721,222 research outputs found
Moving proteins from the cytosol into mitochondria
No full textMitochondria of the yeast Saccharomyces cerevisiae contain at least 750 different proteins, which perform diverse roles. Most of these proteins (approx. 99%) are translated on cytosolic ribosomes, and their import into mitochondria is essential for mitochondrial function. Proteinaceous machineries of great complexity, the so-called translocases, in the mitochondrial membranes mediate the import of these proteins
Moving proteins from the cytosol into mitochondria
No full textMitochondria of the yeast Saccharomyces cerevisiae contain at least 750 different proteins, which perform diverse roles. Most of these proteins (approx. 99%) are translated on cytosolic ribosomes, and their import into mitochondria is essential for mitochondrial function. Proteinaceous machineries of great complexity, the so-called translocases, in the mitochondrial membranes mediate the import of these proteins
INA complex links assembly of the nuclear- and mitochondrial-encoded modules of ATP synthase.
No full text
INA complex links assembly of the nuclear- and mitochondrial-encoded modules of ATP synthase.
No full text
Cytochrome c oxidase biogenesis – from translation to early assembly of the core subunit COX1
No full textMitochondria are the powerhouses of the cell as they produce the majority of ATP with their oxidative phosphorylation (OXPHOS) machinery. The OXPHOS system is composed of the F1Fo ATP synthase and four mitochondrial respiratory chain complexes, the terminal enzyme of which is the cytochrome c oxidase (complex IV) that transfers electrons to oxygen, generating water. Complex IV comprises of 14 structural subunits of dual genetic origin: while the three core subunits are mitochondrial encoded, the remaining constituents are encoded by the nuclear genome. Hence, the assembly of complex IV requires the coordination of two spatially separated gene expression machinery. Recent efforts elucidated an increasing number of proteins involved in mitochondrial gene expression, which are linked to complex IV assembly. Additionally, several COX1 biogenesis factors have been intensively biochemically investigated and an increasing number of structural snapshots shed light on the organization of macromolecular complexes such as the mitoribosome or the cytochrome c oxidase. Here, we focus on COX1 translation regulation and highlight the advanced understanding of early steps during COX1 assembly and its link to mitochondrial translation regulation.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Max Planck Society http://dx.doi.org/10.13039/50110000418
Mitochondrial import and the twin-pore translocase
No full textThe mitochondrial inner membrane is rich in multispanning integral membrane proteins, most of which mediate the vital transport of molecules between the matrix and the intermembrane space. The correct transport and membrane insertion of such proteins is essential for maintaining the correct exchange of molecules between mitochondria and the rest of the cell. Mitochondria contain several specific complexes-known as translocases-that translocate precursor proteins. Recent analysis of the inner-membrane, twin-pore protein translocase (TIM22 complex) allows a glimpse of the molecular mechanisms by which this machinery triggers protein insertion using the membrane potential as an external driving force
Insertion of hydrophobic membrane proteins into the inner mitochondrial membrane - A guided tour
No full textOnly a few mitochondrial proteins are encoded by the organellar genome. The majority of mitochondrial proteins are nuclear encoded and thus have to be transported into the organelle from the cytosol. Within the mitochondrion proteins have to be sorted into one of the four sub-compartments: the outer or inner membranes, the intermembrane space or the matrix. These processes are mediated by complex protein machineries within the different compartments that act alone or in concert with each other. The translocation machinery of the outer membrane is formed by a multisubunit protein complex (TOM complex), that is built up by signal receptors and the general import pore (GIP). The inner membrane houses two multi-subunit protein complexes that each handles special subsets of mitochondrial proteins on their way to their final destination. According to their primary function these two complexes have been termed the presequence translocase (or TIM23 complex) and the protein insertion complex (or TIM22 complex). The identification of components of these complexes and the analysis of the molecular mechanisms underlying their function are currently an exciting and fast developing field of molecular cell biology. (C) 2003 Elsevier Science Ltd. All rights reserved
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