Cloning of a human gene involved in cytochrome oxidase assembly by functional complementation of an oxa1- mutation in Saccharomyces cerevisiae.

Bonnefoy, Nathalie; Kermorgant, Michèle; Groudinsky, Olga; Minét, Michèle; Słonimski, Piotr P.; Dujardin, Geneviève

doi:10.1073/pnas.91.25.11978

Cited by 97 publications

(82 citation statements)

References 29 publications

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“…The Oxa1p protein of yeast mitochondria was previously shown to be required for the correct assembly of cytochrome c oxidase complexes (42,43), and the specific export of the amino and carboxyl termini of the precursor of cytochrome c oxidase subunit II from the mitochondrial matrix to the intermembrane space (21,22,44). Therefore, a possible role of SpoIIIJ and YqjG in the biogenesis of the transmembrane lipoproteins CtaC and QoxA, which are orthologues of cytochrome c oxidase subunit II (45), was investigated.…”

Section: Specific Role Of Spoiiij and Yqjg In Membrane Protein Stabilmentioning

confidence: 99%

Complementary Impact of Paralogous Oxa1-like Proteins of Bacillus subtilis on Post-translocational Stages in Protein Secretion

Tjalsma

Bron

Dijl

2003

Journal of Biological Chemistry

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In mitochondria, chloroplasts, and Gram-negative eubacteria, Oxa1p(-like) proteins are critical for the biogenesis of membrane proteins. Here we show that the Gram-positive eubacterium Bacillus subtilis contains two functional Oxa1p orthologues, denoted SpoIIIJ and YqjG. The presence of either SpoIIIJ or YqjG is required for cell viability. Whereas SpoIIIJ is required for sporulation, YqjG is dispensable for this developmental process. The stability of two membrane proteins was found to be mildly affected upon SpoIIIJ limitation in the absence of YqjG. Surprisingly, the topology and stability of other membrane proteins remained unaffected under these conditions. In contrast, SpoIIIJ-and YqjGlimiting conditions resulted in a strong post-translocational defect in the stability of secretory proteins. Together, these data indicate that SpoIIIJ and YqjG of B. subtilis are involved in both membrane protein biogenesis and protein secretion. However, the reduced stability of secretory proteins seems to be the most prominent phenotype of SpoIIIJ/YqjG-depleted B. subtilis cells. In conclusion, our observations show that SpoIIIJ and YqjG have different, but overlapping functions in B. subtilis. Most importantly, it seems that different members of the Oxa1p protein family have acquired at least partly distinct, species-specific, functions that are essential for life.

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Section: Specific Role Of Spoiiij and Yqjg In Membrane Protein Stabilmentioning

confidence: 99%

Complementary Impact of Paralogous Oxa1-like Proteins of Bacillus subtilis on Post-translocational Stages in Protein Secretion

Tjalsma

Bron

Dijl

2003

Journal of Biological Chemistry

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“…Oxa1p is a nuclear encoded mitochondrial protein of the yeast Saccharomyces cerevisiae which is conserved from prokaryotes throughout eukaryotes (11)(12)(13). Found in both Grampositive and Gram-negative bacteria, the function of the prokaryotic homologues of Oxa1p, termed 60-kDa inner membrane protein, has not been identified.…”

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confidence: 99%

Oxa1p, an essential component of the N-tail protein export machinery in mitochondria

Hell

Herrmann

Pratje

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

211

208

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A number of nuclear encoded inner membrane proteins of mitochondria span the membrane in such a manner that their N termini are located in the intermembrane space. Many of these proteins attain this membrane orientation by undergoing an export step from the matrix across the inner membrane. This export process, which resembles bacterial N-tail export from energetic and topogenic signal requirements, is facilitated by Oxa1p, a protein that has homologues throughout prokaryotes and eukaryotes. Oxa1p, as we have previously shown, is required to export the N and C termini of the mitochondrially encoded pCoxII to the intermembrane space. We demonstrate here that imported nuclear encoded proteins physically interact with Oxa1p and depend on Oxa1p for efficient export of their N termini to the intermembrane space. Furthermore, Oxa1p interacts with nascent polypeptide chains synthesized in mitochondria, including the fully synthesized pCoxII and CoxIII species. Thus, Oxa1p represents a component of a general export machinery of the mitochondrial inner membrane.

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“…Oxa1p interacts with nascent mitochondrial polypeptides and it has been proposed that it could act as part of a general membrane insertion machinery (15). Oxa1p is functionally conserved in fission yeast, human and plant mitochondria (16)(17)(18) and in chloroplasts, its homologue Alb3 plays a role in the insertion of the light harvesting chlorophyll-binding proteins into the thylakoid (19,20).…”

mentioning

confidence: 99%

Role of positively charged transmembrane segments in the insertion and assembly of mitochondrial inner-membrane proteins

Saint-Georges¹,

Hamel²,

Lemaire³

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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The biogenesis of membrane oligomeric complexes is an intricate process that requires the insertion and assembly of transmembrane (TM) domains into the lipid bilayer. The Oxa1p family plays a key role in this process in organelles and bacteria. T he biogenesis of membrane oligomeric complexes is an intricate process that requires the membrane targeting of subunits, their insertion into the lipid bilayer, folding with cofactors, and the assembly into a functional structure. Numerous studies in bacterial or eukaryotic cells have demonstrated that most membrane proteins insert at the translocon site and that this process is driven by hydrophobic transmembrane (TM) domains (1, 2). However, very little is known about the lateral exit of TM domains from the site of insertion into the lipid bilayer and about the mechanistic details of subunit assembly into functional complexes. The mitochondrial respiratory chain enzymes are complexes composed of numerous nonidentical subunits (Fig. 1). Their biogenesis requires the participation of nucleus-encoded factors that are not intrinsic components of the complexes and are imported into mitochondria by using a sophisticated translocation machinery (3-5). Most of these proteins are conserved through evolution and it has been shown that mutations in the genes encoding subunits of the respiratory complexes or assembly assisting proteins are the direct cause of several human neurodegenerative pathologies (ref. 6, for review).Oxa1p, a membrane protein conserved from bacteria to eukaryotic organelles, is a key component of the insertion machinery of membrane proteins. The Escherichia coli homologue YidC interacts with the Sec translocase and mediates the insertion of a subset of proteins into the bacterial membrane (7,8). In yeast mitochondria, the absence of Oxa1p leads to a complete loss of respiration associated with severe defects in the insertion and assembly of subunits of the Cox and ATPase complexes and with minor defects in the assembly of the bc1 complex (9-11). The translocation and maturation of the Cox subunit, Cox2p, is almost completely blocked (12, 13) and several other membrane subunits are degraded (14). Oxa1p interacts with nascent mitochondrial polypeptides and it has been proposed that it could act as part of a general membrane insertion machinery (15). Oxa1p is functionally conserved in fission yeast, human and plant mitochondria (16-18) and in chloroplasts, its homologue Alb3 plays a role in the insertion of the light harvesting chlorophyll-binding proteins into the thylakoid (19,20).The functional conservation of Oxa1p through evolution suggests a crucial role in the mechanism of protein insertion into the membrane, but its precise function remains poorly understood. Interestingly, we found that its absence in yeast mitochondria can be partially compensated for by different mutations. First, ATP synthase assembly and activity is fully restored in a strain lacking the mitochondrial protease Yme1p (14). Second, we have isolated several suppressor mutations in th...

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Cloning of a human gene involved in cytochrome oxidase assembly by functional complementation of an oxa1- mutation in Saccharomyces cerevisiae.

Cited by 97 publications

References 29 publications

Complementary Impact of Paralogous Oxa1-like Proteins of Bacillus subtilis on Post-translocational Stages in Protein Secretion

Complementary Impact of Paralogous Oxa1-like Proteins of Bacillus subtilis on Post-translocational Stages in Protein Secretion

Oxa1p, an essential component of the N-tail protein export machinery in mitochondria

Role of positively charged transmembrane segments in the insertion and assembly of mitochondrial inner-membrane proteins

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