Properties of the C-terminal Tail of Human Mitochondrial Inner Membrane Protein Oxa1L and Its Interactions with Mammalian Mitochondrial Ribosomes

Haque, Md. Emdadul; Elmore, Kevin B.; Tripathy, Ashutosh; Koç, Hasan; Koc, Emine C.; Spremulli, Linda L.

doi:10.1074/jbc.m110.148262

Cited by 43 publications

(43 citation statements)

References 45 publications

(62 reference statements)

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“…In contrast to its bacterial homologs, Oxa1 contains a C-terminal stretch region of ϳ100 amino acid residues that protrudes into the matrix. This region is of ␣-helical amphipathic structure and is rich in positively charged residues (11)(12)(13)(14)(15). It was speculated that the C-terminal region of Oxa1 tethers the ribosome to the insertion complex so that nascent chains are threaded efficiently across the membrane.…”

Section: Insertion Of Linkers Causes Growth Defects On Non-fermentablmentioning

confidence: 99%

“…Presumably due to its specialization in the synthesis of hydrophobic membrane proteins, the mitochondrial ribosome is tightly associated with the mitochondrial inner membrane and, at least in yeast, can only be released upon treatment with detergent or urea (9,10). Moreover, mitochondrial ribosomes are physically bound to the protein insertion machinery of the inner membrane (11)(12)(13)(14)(15). Membrane insertion of nascent chains is facilitated by Oxa1, which integrates both mitochondrial translation products and some nuclear encoded proteins into the inner membrane (16 -18).…”

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confidence: 99%

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Oxa1-Ribosome Complexes Coordinate the Assembly of Cytochrome c Oxidase in Mitochondria

Keil

Bareth

Woellhaf

et al. 2012

Journal of Biological Chemistry

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Section: Insertion Of Linkers Causes Growth Defects On Non-fermentablmentioning

confidence: 99%

mentioning

confidence: 99%

Oxa1-Ribosome Complexes Coordinate the Assembly of Cytochrome c Oxidase in Mitochondria

Keil

Bareth

Woellhaf

et al. 2012

Journal of Biological Chemistry

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“…Previous studies of the C-terminal tail of human Oxa1L (Oxa1L-CTT) 2 suggested that, in solution, the C-terminal tail exists as an equilibrium of the monomer, dimer, and tetramer forms (8). Circular dichroism studies indicated that it contains ϳ20% ␣-helical content.…”

mentioning

confidence: 99%

Identification of Protein-Protein and Protein-Ribosome Interacting Regions of the C-terminal Tail of Human Mitochondrial Inner Membrane Protein Oxa1L

Haque

Spremulli

Fecko

2010

Journal of Biological Chemistry

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The mammalian mitochondrial inner membrane protein Oxa1L is involved in the insertion of a number of mitochondrial translation products into the inner membrane. During this process, the C-terminal tail of Oxa1L (Oxa1L-CTT) binds mitochondrial ribosomes and is believed to coordinate the synthesis and membrane insertion of the nascent chains into the membrane. The C-terminal tail of Oxa1L does not contain any Cys residues. Four variants of this protein with a specifically placed Cys residue at position 4, 39, 67, or 94 of Oxa1L-CTT have been prepared. These Cys residues have been derivatized with a fluorescent probe, tetramethylrhodamine-5-maleimide, for biophysical studies. Oxa1L-CTT forms oligomers cooperatively with a binding constant in the submicromolar range. Mammalian mitochondria synthesize 13 hydrophobic proteins that are components of the respiratory chain complexes in the inner membrane. Protein synthesis in this organelle is performed by specialized ribosomes, which are quite distinct from the ribosomes of other translational systems. In particular, they are quite rich in protein and have truncated rRNAs (1). Because of the presence of regions of high hydrophobicity, mitochondrially synthesized proteins are thought to be integrated into the membrane during or immediately following their synthesis on mitochondrial ribosomes.Mitochondrial ribosomes are associated with the inner membrane (2, 3), and several proteins have been implicated in the binding of these ribosomes to the membrane. The best characterized of these are members of the Oxa1 family of proteins. Oxa1 is located in the inner membrane, where it acts as a component of the machinery that mediates the insertion of certain hydrophobic proteins into the membrane. It belongs to the YidC and Alb3 family of proteins found throughout prokaryotes and eukaryotes (4, 5). The human form is designated Oxa1L. Oxa1L consists of an N-terminal section located in the mitochondrial intermembrane space, five transmembrane helices, and a C-terminal tail of ϳ100 amino acids exposed in the mitochondrial matrix (6).The C-terminal tail of the yeast homolog of Oxa1L (Oxa1p) has been shown to bind mitochondrial ribosomes (6). Deletion of this region of Oxa1p severely diminishes the efficiency of membrane insertion of subunit II of cytochrome oxidase, indicating that the C-terminal tail of yeast Oxa1p plays an active role in the insertion of mitochondrial translation products into the lipid bilayer (6). Cryo-EM studies of yeast Oxa1p bound to bacterial ribosomes indicate that it interacts near the exit tunnel located on the back of the large ribosomal subunit (7).Previous studies of the C-terminal tail of human Oxa1L (Oxa1L-CTT) 2 suggested that, in solution, the C-terminal tail exists as an equilibrium of the monomer, dimer, and tetramer forms (8). Circular dichroism studies indicated that it contains ϳ20% ␣-helical content. Despite predictions based on yeast Oxa1p, human Oxa1L-CTT does not form a coiled-coil structure. Two copies of Oxa1L-CTT bind to ribosomes with a ...

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“…The altered translational profile may enhance the overall fitness of the cells and increase the tolerance of the cells, then and the organisms can against harmful chemicals, such as amycin. It has been reported the expression of ribosomal proteins was important for mitochondrial biogenesis (Haque et al, 2010). Since mitochondria are the organelles responsible for the oxidation reaction, their increase can accelerate the rate to detoxify amycin.…”

Section: Discussionmentioning

confidence: 99%

Drug Resistance Effects of Ribosomal Protein L24 Overexpression in Hepatocellular Carcinoma HepG2 Cells

Guo¹,

Kong²,

Liu³

et al. 2014

Asian Pacific Journal of Cancer Prevention

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Properties of the C-terminal Tail of Human Mitochondrial Inner Membrane Protein Oxa1L and Its Interactions with Mammalian Mitochondrial Ribosomes

Cited by 43 publications

References 45 publications

Oxa1-Ribosome Complexes Coordinate the Assembly of Cytochrome c Oxidase in Mitochondria

Oxa1-Ribosome Complexes Coordinate the Assembly of Cytochrome c Oxidase in Mitochondria

Identification of Protein-Protein and Protein-Ribosome Interacting Regions of the C-terminal Tail of Human Mitochondrial Inner Membrane Protein Oxa1L

Drug Resistance Effects of Ribosomal Protein L24 Overexpression in Hepatocellular Carcinoma HepG2 Cells

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