Synthesis and Intracellular Transport of Mitochondrial Proteins

Harmey, Matthew A.; Neupert, Walter

doi:10.1007/978-1-4684-4604-3_13

Cited by 25 publications

(13 citation statements)

References 112 publications

(92 reference statements)

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“…A number of general features of the transport of proteins into mitochondria have been elucidated (for reviews see Hay et al, 1984;Harmey and Neupert, 1985). First, completed polypeptide chains are released as precursors, most of which carry amino-terminal peptide extensions, from cytoplasmic ribosomes into precursor pools in the cytosol (Hallermayer et al, 1977;Schatz, 1979).…”

Section: Introductionmentioning

confidence: 99%

Transport into mitochondria and intramitochondrial sorting of the Fe/S protein of ubiquinol-cytochrome c reductase

Hartl

Schmidt

Wächter

et al. 1986

Cell

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322

214

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Section: Introductionmentioning

confidence: 99%

Transport into mitochondria and intramitochondrial sorting of the Fe/S protein of ubiquinol-cytochrome c reductase

Hartl

Schmidt

Wächter

et al. 1986

Cell

Self Cite

322

214

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“…Transport of proteins into mitochondria can be subdivided into several distinct steps (for reviews see Hay et al, 1984;Harmey and Neupert, 1985;Pfanner and Neupert, 1987): Nuclear-coded mitochondrial proteins are synthesized on free polysomes as precursors, most df which have aminoterminal peptide extensions, and are released into cytosolic pools (Hallermayer et al, 1977;Schatz, 1979). Precursors are located to mitochondria via targeting signals contained either in the presequences or in some cases in the mature parts of the precursors (Hurt et al, 1984a;1984b;Horwich et al, 1985;Pfanner et al, 1987b).…”

Section: Introductionmentioning

confidence: 99%

Successive translocation into and out of the mitochondrial matrix: Targeting of proteins to the intermembrane space by a bipartite signal peptide

Hartl¹,

Ostermann²,

Guiard

et al. 1987

Cell

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270

143

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SummaryWe investigated the import and sorting pathways of cytochrome b2 and cytochrome cl, which are functionally located in the intermembrane space of mitochondria. Both proteins are synthesized on cytoplasmic ribosomes as larger precursors and are processed in mitochondria in two steps upon import. The precursors are first translocated across both mitochondrial membranes via contact sites into the matrix. Processing by the matrix peptidase leads to intermediatesized forms, which art? subsequently redirected across the inner membrane. The second proteolytic processing occurs in the intermembrane space. We conclude that the hydrophobic stretches in the presequences of the intermediate-sizedforms do not stop transfer across the inner membrane, but rather act as transport signals to direct export from the matrix into the intermembrane space.

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“…Apocytochrome c, the precursor of holocytochrome c, is synthesized on free cytoplasmic ribosomes, released into the cytosol and imported into mitochondria in a post-translational manner. Unlike many other precursor proteins, however, apocytochrome c is not synthesized with an amino-terminal prepiece and thus is not proteolytically processed upon import into mitochondria (for reviews see Harmey and Neupert, 1985;Zimmermann, 1986;. Apocytochrome c, a basic protein, can penetrate spontaneously into artificial lipid bilayers (Rietveld et al, 1985) and thus it is probably able to insert spontaneously (at least partially) into the outer mitochondrial mem- (74A, wild-type) poly(A)+ mRNA was cloned into the PstI site of pBR322 by dG/dC tailing.…”

Section: Introductionmentioning

confidence: 99%

Deficiency in mRNA splicing in a cytochrome c mutant of neurospora crassa: importance of carboxy terminus for import of apocytochrome c into mitochondria.

Stuart¹,

Neupert²,

Tropschug³

1987

The EMBO Journal

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Molecular cloning and characterization of cytochrome c cDNA clones of Neurospora crassa wild‐type (74A) and a cytochrome c‐deficient mutant (cyc1‐1) are described. Southern blot analysis of genomic DNA indicates that only one cytochrome c gene exists in the N. crassa genome. The cDNA sequence of the wild‐type cytochrome c confirmed the previously determined protein sequence. Sequence analysis of the cyc1‐1 cDNA for cytochrome c revealed the presence of a larger open reading frame, owing to the presence of an unspliced intron in the 3′ end of the coding region. Splicing of this intron is obviously prevented due to the presence of two base exchanges in the highly conserved intron consensus sequences. Consequently, cyc1‐1 synthesizes apocytochrome c with an altered carboxy terminus, 19 amino acids longer than the wild‐type cytochrome c, with the final 27 amino acids being of an unrelated sequence. This alteration in the carboxy terminus renders the apocytochrome c incompetent for binding to mitochondria and, consequently, import into mitochondria. Thus, unlike other mitochondrial precursor proteins, where it has been demonstrated that the amino terminus alone is sufficient to target the protein to the mitochondria, an intact carboxy terminus is required for efficient import of apocytochrome c into mitochondria. This is independent confirmation for the view that the import pathway of cytochrome c is unique with respect to all other mitochondrial proteins studied to date.

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Synthesis and Intracellular Transport of Mitochondrial Proteins

Cited by 25 publications

References 112 publications

Transport into mitochondria and intramitochondrial sorting of the Fe/S protein of ubiquinol-cytochrome c reductase

Transport into mitochondria and intramitochondrial sorting of the Fe/S protein of ubiquinol-cytochrome c reductase

Successive translocation into and out of the mitochondrial matrix: Targeting of proteins to the intermembrane space by a bipartite signal peptide

Deficiency in mRNA splicing in a cytochrome c mutant of neurospora crassa: importance of carboxy terminus for import of apocytochrome c into mitochondria.

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