<i>MBA1</i> encodes a mitochondrial membrane‐associated protein required for biogenesis of the respiratory chain

Rep, Martijn; Grivell, Leslie A.

doi:10.1016/0014-5793(96)00543-1

Cited by 23 publications

(34 citation statements)

References 24 publications

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“…2C). Mba1 has been implicated in the process of insertion of newly synthesized translation products by aligning the mitochondrial ribosome with the membrane insertion machinery (22–25). To support the mass spectrometric data, Cox20 ProtA -containing complexes were purified from mitochondria, and the purified fraction was analyzed by Western blotting (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Cotranslational insertion of the Cox2 N-terminal tail together with the first transmembrane span depends on the export machinery, Oxa1 (17–19). The peripheral inner membrane protein Mba1 cooperates with Oxa1 in the insertion of mitochondrial translation products (20–25). Mba1 is thought to align the ribosomal exit tunnel with the export machinery (23).…”

Section: Introductionmentioning

confidence: 99%

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Ribosome-Associated Mba1 Escorts Cox2 from Insertion Machinery to Maturing Assembly Intermediates

Lorenzi

Oeljeklaus

Ronsör

et al. 2016

Molecular and Cellular Biology

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The three conserved core subunits of the cytochrome c oxidase are encoded by mitochondria in close to all eukaryotes. The Cox2 subunit spans the inner membrane twice, exposing the N and C termini to the intermembrane space. For this, the N terminus is exported cotranslationally by Oxa1 and subsequently undergoes proteolytic maturation in Saccharomyces cerevisiae. Little is known about the translocation of the C terminus, but Cox18 has been identified to be a critical protein in this process. Here we find that the scaffold protein Cox20, which promotes processing of Cox2, is in complex with the ribosome receptor Mba1 and translating mitochondrial ribosomes in a Cox2-dependent manner. The Mba1-Cox20 complex accumulates when export of the C terminus of Cox2 is blocked by the loss of the Cox18 protein. While Cox20 engages with Cox18, Mba1 is no longer present at this stage. Our analyses indicate that Cox20 associates with nascent Cox2 and Mba1 to promote Cox2 maturation cotranslationally. We suggest that Mba1 stabilizes the Cox20-ribosome complex and supports the handover of Cox2 to the Cox18 tail export machinery.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ribosome-Associated Mba1 Escorts Cox2 from Insertion Machinery to Maturing Assembly Intermediates

Lorenzi

Oeljeklaus

Ronsör

et al. 2016

Molecular and Cellular Biology

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“…This module was characterized by enrichment for two functional categories: "respiration" (10 genes) and "mitochondrial biogenesis" (14 genes). The category of "respiration" comprised genes encoding various subunits of the F o (ATP4, ATP14, ATP18, and ATP20) and F 1 (ATP3 and ATP15) domains of mitochondrial ATP synthase (16) but also COX23, COX14, MAM33, and MBA1, involved in the assembly of respiratory complexes in mitochondria (3,27,60,67). The relationship between Zn availability and these proteins remains unclear, although cytochrome c oxidase activity has been shown to be inhibited by Zn.…”

Section: Resultsmentioning

confidence: 99%

Physiological and Transcriptional Responses of Saccharomyces cerevisiae to Zinc Limitation in Chemostat Cultures

Nicola

Hazelwood

Hulster

et al. 2007

Appl Environ Microbiol

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Transcriptional responses of the yeast Saccharomyces cerevisiae to Zn availability were investigated at a fixed specific growth rate under limiting and abundant Zn concentrations in chemostat culture. To investigate the context dependency of this transcriptional response and eliminate growth rate-dependent variations in transcription, yeast was grown under several chemostat regimens, resulting in various carbon (glucose), nitrogen (ammonium), zinc, and oxygen supplies. A robust set of genes that responded consistently to Zn limitation was identified, and the set enabled the definition of the Zn-specific Zap1p regulon, comprised of 26 genes and characterized by a broader zinc-responsive element consensus (MHHAACCBYNMRGGT) than so far described. Most surprising was the Zn-dependent regulation of genes involved in storage carbohydrate metabolism. Their concerted down-regulation was physiologically relevant as revealed by a substantial decrease in glycogen and trehalose cellular content under Zn limitation. An unexpectedly large number of genes were synergistically or antagonistically regulated by oxygen and Zn availability. This combinatorial regulation suggested a more prominent involvement of Zn in mitochondrial biogenesis and function than hitherto identified.

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“…Export of the Cox2p N-terminal hydrophilic domain depends on Oxa1p, a translocase component embedded in the inner membrane (Bonnefoy et al, 1994a;Altamura et al, 1996;He and Fox, 1997;Hell et al, 1997;Kermorgant et al, 1997;Hell et al, 1998). Another inner membrane protein, Mba1p (Rep and Grivell, 1996), is also involved in N-tail export (Preuss et al, 2001). After export, a 15-amino acid leader peptide is removed from the N terminus by a protease comprised of Imp1p, Imp2p, and Som1p (Schneider et al, 1991;Nunnari et al, 1993;Jan et al, 2000), in a reaction facilitated by the interaction of preCox2p with the inner membrane protein Cox20p (Hell et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Cox18p Is Required for Export of the Mitochondrially EncodedSaccharomyces cerevisiaeCox2p C-Tail and Interacts with Pnt1p and Mss2p in the Inner Membrane

Saracco

Fox

2002

MBoC

114

130

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The amino- and carboxy-terminal domains of mitochondrially encoded cytochrome c oxidase subunit II (Cox2p) are translocated out of the matrix to the intermembrane space. We have carried out a genetic screen to identify components required to export the biosynthetic enzyme Arg8p, tethered to the Cox2p C terminus by a translational gene fusion inserted into mtDNA. We obtained multiple alleles of COX18, PNT1, and MSS2, as well as mutations in CBP1 and PET309. Focusing on Cox18p, we found that its activity is required to export the C-tail of Cox2p bearing a short C-terminal epitope tag. This is not a consequence of reduced membrane potential due to loss of cytochrome oxidase activity because Cox2p C-tail export was not blocked in mitochondria lacking Cox4p. Cox18p is not required to export the Cox2p N-tail, indicating that these two domains of Cox2p are translocated by genetically distinct mechanisms. Cox18p is a mitochondrial integral inner membrane protein. The inner membrane proteins Mss2p and Pnt1p both coimmunoprecipitate with Cox18p, suggesting that they work together in translocation of Cox2p domains, an inference supported by functional interactions among the three genes.

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MBA1 encodes a mitochondrial membrane‐associated protein required for biogenesis of the respiratory chain

Cited by 23 publications

References 24 publications

Ribosome-Associated Mba1 Escorts Cox2 from Insertion Machinery to Maturing Assembly Intermediates

Ribosome-Associated Mba1 Escorts Cox2 from Insertion Machinery to Maturing Assembly Intermediates

Physiological and Transcriptional Responses of Saccharomyces cerevisiae to Zinc Limitation in Chemostat Cultures

Cox18p Is Required for Export of the Mitochondrially EncodedSaccharomyces cerevisiaeCox2p C-Tail and Interacts with Pnt1p and Mss2p in the Inner Membrane

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