Protein export from the mitochondrial matrix

Poyton, Robert O.; Duhl, David M.; Clarkson, G H D

doi:10.1016/0962-8924(92)90049-s

Cited by 38 publications

(31 citation statements)

References 42 publications

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“…For example, it could organize other mitochondrial chaperones (mtHsp70) or translocation machinery components (Pnt1p, Oxa1p, and Cox18p). Implicit in this proposal is the idea that Cox2p C-tail export may be a posttranslational process (see below), in contrast to N-tail export, which is likely to occur during synthesis (21,24,42).…”

Section: Discussionmentioning

confidence: 99%

“…The crystal structures of both bovine and Paracoccus denitrificans cytochrome oxidases have been determined (37,61). Based on these structures and on other studies (42), the orientation of yeast Cox2p in the inner membrane has been firmly established. After or during synthesis, the amino-and carboxy-terminal tails of Cox2p are exported from the matrix into the intermembrane space (IMS), while its two transmembrane domains are embedded in the inner membrane.…”

mentioning

confidence: 97%

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Peripheral Mitochondrial Inner Membrane Protein, Mss2p, Required for Export of the Mitochondrially Coded Cox2p C Tail in Saccharomyces cerevisiae

Broadley

Demlow

Fox

2001

Molecular and Cellular Biology

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Cytochrome oxidase subunit 2 (Cox2p) is synthesized on the matrix side of the mitochondrial inner membrane, and its N-and C-terminal domains are exported across the inner membrane by distinct mechanisms. The Saccharomyces cerevisiae nuclear gene MSS2 was previously shown to be necessary for Cox2p accumulation. We have used pulse-labeling studies and the expression of the ARG8 m reporter at the COX2 locus in an mss2 mutant to demonstrate that Mss2p is not required for Cox2p synthesis but rather for its accumulation. Mutational inactivation of the proteolytic function of the matrix-localized Yta10p (Afg3p) AAA-protease partially stabilizes Cox2p in an mss2 mutant but does not restore assembly of cytochrome oxidase. In the absence of Mss2p, the Cox2p N terminus is exported, but Cox2p C-terminal export and assembly of Cox2p into cytochrome oxidase is blocked. Epitope-tagged Mss2p is tightly, but peripherally, associated with the inner membrane and protected by it from externally added proteases. Taken together, these data indicate that Mss2p plays a role in recognizing the Cox2p C tail in the matrix and promoting its export.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 97%

Peripheral Mitochondrial Inner Membrane Protein, Mss2p, Required for Export of the Mitochondrially Coded Cox2p C Tail in Saccharomyces cerevisiae

Broadley

Demlow

Fox

2001

Molecular and Cellular Biology

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“…Subunits I, II, and III are products of mitochondrial genes (COX1, COX2, and COX3, respectively) (1,6) and make up the catalytic core of the enzyme (7,8). All three of these polypeptides are translated on mitochondrial ribosomes and are inserted co-translationally into the mitochondrial inner membrane (9), a process termed mitochondrial export (10,11). Subunits IV, V, Va or Vb, VI, VII, and VIIa are encoded by nuclear COX genes (COX4, COX5a or 5b, COX6, COX7, COX8, and COX9, respectively).…”

mentioning

confidence: 99%

“…The two different pathways followed by compartmentally separated gene products, import of nuclear-encoded proteins (14) and export of mitochondrially encoded proteins (10,11), must converge at some point into an assembly pathway during the biogenesis of holocytochrome c oxidase. Although the mitochondrial import pathways have been elucidated (for review, see Ref.…”

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A Role for Pet100p in the Assembly of Yeast Cytochrome c Oxidase

Church¹,

Goehring

Forsha

et al. 2005

Journal of Biological Chemistry

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“…Each of the mitochondrially encoded respiratory-chain subunits of Saccharomyces cerevisiae contains at least one hydrophilic tail or loop that is exported to the outside surface of the inner membrane by translocation across the lipid bilayer (48). In addition to their important role in assembly of the respiratory complexes, mitochondrial export translocation systems might play a role in transporting mitochondrially encoded polypeptides out of the organelle in animal (9) and plant (1) cells.…”

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confidence: 99%

Mutations Affecting a Yeast Mitochondrial Inner Membrane Protein, Pnt1p, Block Export of a Mitochondrially Synthesized Fusion Protein from the Matrix

Fox

1999

Molecular and Cellular Biology

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The machinery that inserts mitochondrially encoded proteins into the inner membrane and translocates their hydrophilic domains through the membrane is poorly understood. We have developed a genetic screen for Saccharomyces cerevisiae mutants defective in this export process. Here we show that mutations in the nuclear gene PNT1 block the translocation of mitochondrially encoded fusion proteins across the inner membrane. Pnt1p is a mitochondrial integral inner membrane protein that appears to have two hydrophilic domains in the matrix, flanking a central hydrophobic hairpin-like anchor. While an S. cerevisiae pnt1 deletion mutant was more sensitive to H 2 O 2 than the wild type was, it was respiration competent and able to export wild-type Cox2p. However, deletion of the PNT1 orthologue from Kluyveromyces lactis, KlPNT1, caused a clear nonrespiratory phenotype, absence of cytochrome oxidase activity, and a defect in the assembly of KlCox2p that appears to be due to a block of C-tail export. Since PNT1 was previously described as a gene affecting resistance to the antibiotic pentamidine, our data support a mitochondrial target for this drug.

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Protein export from the mitochondrial matrix

Cited by 38 publications

References 42 publications

Peripheral Mitochondrial Inner Membrane Protein, Mss2p, Required for Export of the Mitochondrially Coded Cox2p C Tail in Saccharomyces cerevisiae

Peripheral Mitochondrial Inner Membrane Protein, Mss2p, Required for Export of the Mitochondrially Coded Cox2p C Tail in Saccharomyces cerevisiae

A Role for Pet100p in the Assembly of Yeast Cytochrome c Oxidase

Mutations Affecting a Yeast Mitochondrial Inner Membrane Protein, Pnt1p, Block Export of a Mitochondrially Synthesized Fusion Protein from the Matrix

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