The protein import machinery of mitochondria

Schatz, Gottfried

doi:10.1002/pro.5560020202

Cited by 85 publications

(35 citation statements)

References 25 publications

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“…This is consistent with the model that MAS17 forms a core complex of the protein translocation machinery in the outer membrane with ISP42 and MAS20 but not with MAS70. 2 In Vitro Import of Precursor Proteins into Mitochondria Containing MAS17⌬120 -152-We then asked if replacement of MAS17 by MAS17⌬120 -152 affects protein import into isolated mitochondria in vitro. We prepared wild-type mitochondria and MAS17⌬120 -152-containing mitochondria as described above and tested in vitro import of several mitochondrial precursor proteins (Fig.…”

Section: B Sectors 2 and 4) These Results Indicate That The Membramentioning

confidence: 99%

“…Nuclear-encoded mitochondrial precursor proteins are imported from the cytosol into mitochondria; they are recognized by cytosolic factors and/or mitochondrial receptor proteins and are subsequently translocated across the outer and inner mitochondrial membranes (1,2). Translocation across the mitochondrial membranes requires coordinated functions of two separate machineries in the outer and inner mitochondrial membranes; they most likely interact transiently to allow the movement of precursor proteins into the matrix (3,4).…”

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confidence: 99%

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Mitochondrial Receptor Complex Protein

Nakai

Kinoshita

Endo

1995

Journal of Biological Chemistry

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MAS17 (MAS22)is an essential component of the import receptor complex in the yeast mitochondrial outer membrane. MAS17 consists of three distinct domains: the N-terminal cytosolic domain, the internal membrane-spanning domain, and the C-terminal intermembrane space domain. In the present study, we examined the roles of the C-terminal domain of MAS17, which is rich in acidic amino acids, in protein import into mitochondria both in vivo and in vitro. Cells expressing MAS17⌬120 -152, a mutant MAS17 lacking the C-terminal acidic domain, could grow as fast as those expressing wild-type MAS17, while cells expressing MAS17⌬97-152, a mutant MAS17 lacking both the intermembrane space and the membrane-spanning domains, stopped growing as soon as wild-type MAS17 was depleted. MAS17⌬120 -152 was correctly integrated into the mitochondrial outer membrane like wild-type MAS17. Mitochondria containing MAS17⌬120 -152 instead of wildtype MAS17 could import both authentic and artificial mitochondrial precursor proteins nearly as efficiently as wild-type mitochondria in vitro. These results suggest that the C-terminal intermembrane space domain of MAS17 is not essential for targeting or functions of MAS17.

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Section: B Sectors 2 and 4) These Results Indicate That The Membramentioning

confidence: 99%

mentioning

confidence: 99%

Mitochondrial Receptor Complex Protein

Nakai

Kinoshita

Endo

1995

Journal of Biological Chemistry

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“…Most mitochondrial proteins are encoded by nuclear genes, synthesized as precursors on cytosolic ribosomes, translocated into mitochondria and sorted to the specific mitochondrial subcompartment where they fulfill their function (Hannavy et al, 1993;Kiebler et al, 1993a;Schatz, 1993;Segui-Real et al, 1993). The process of translocating precursor proteins across the membranes requires two separate machineries in the outer and inner mitochondrial membranes.…”

Section: Introductionmentioning

confidence: 99%

‘Sheltered disruption’ of Neurospora crassa MOM22, an essential component of the mitochondrial protein import complex.

et al. 1995

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MOM22 is a component of the protein import complex of the mitochondrial outer membrane of Neurospora crassa. Using the newly developed procedure of 'sheltered disruption', we created a heterokaryotic strain harboring two nuclei, one with a null allele of the mom-22 gene and the other with a wild-type allele. Homokaryons bearing the mom-22 disruption could not be isolated, suggesting that mom-22 is an essential gene. The mutant nucleus can be forced to predominate in the heterokaryon through the use of specific nutritional and inhibitor resistance markers. Cultivation of the heterokaryon under conditions favoring the mutant nucleus resulted in selective depletion of MOM22. MOM22-depleted cells did not grow and contained mitochondria with an altered morphology and protein composition. Protein import into isolated, MOM22-depleted mitochondria was abolished for most precursor proteins destined for all subcompartments. In contrast, precursors of MOM19, MOM22 and MOM72 became inserted normally into the outer membrane, defining a novel MOM22-independent import pathway which remained intact in mutant mitochondria. Furthermore, the specific binding of the ADP/ATP carrier to the outer membrane was unaffected, but subsequent transport across the outer membrane did not occur. Our data show that MOM22 is an essential component of Neurospora cells specifically required for the biogenesis of mitochondria.

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“…However, this is not necessarily the only site of cleavage in the signal sequence. An unusually long signal sequence could mean that, as for some mitochondria1 proteins, a two-step processing occurs (Schatz, 1993). In this respect it is notable that the criteria of von Heijne (1987) predict not only the cleavage site deduced in this study but also a further cleavage site between residues 25 and 26.…”

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confidence: 62%

Sequence and expression of the gene encoding the respiratory nitrous‐oxide reductase from Paracoccus denitrificans

Hoeren

Berks

Ferguson

et al. 1993

European Journal of Biochemistry

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The structural gene for the respiratory nitrous-oxide reductase from Paracoccus denitrijicans has been cloned using a probe derived from the structural gene, nosZ, for this enzyme from Pseudomonas stutzeri. The cloned gene could be expressed surprisingly well (presumably yielding an apo-protein) using an expression vector in Escherichia coli.Sequencing the nos2 gene from P. denitrificans has shown that the periplasmic nitrous-oxide reductase of this organism is highly similar in sequence to previously derived primary sequences for the enzyme from three other organisms. As with the other reductases, an unusually long signal sequence is deduced and a common motif of GXXRRXXLG near the beginning of this sequence is present. The results of N-terminal sequencing of the mature nitrous-oxide reductase from the closely related organism Thiosphaera pantotropha indicate that processing of the P. denitrifcans precursor occurs between amino acids at positions 57 and 58. The predicted signal peptide is therefore of the same length and of similar overall structure to that previously described for the P. denitrificans methylamine dehydrogenase small subunit (MauA). The P: denitrifcans sequence for the mature nitrous-oxide reductase reduces from 14 to 11 and 6 to 4, respectively, the number of conserved histidine and methionine residues compared to previous sequences. Three cysteine and four tryptophan residues, previously identified as conserved amongst nitrous-oxide reductases, are found in the Paracoccus enzyme. A comparison of the sequence of the C-terminal region of the nitrous-oxidereductase sequence with that for the Cu, region of subunit I1 of the cytochrome aa3 from P. denit@-cans reveals considerable sequence similarities.

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The protein import machinery of mitochondria

Cited by 85 publications

References 25 publications

Mitochondrial Receptor Complex Protein

Mitochondrial Receptor Complex Protein

‘Sheltered disruption’ of Neurospora crassa MOM22, an essential component of the mitochondrial protein import complex.

Sequence and expression of the gene encoding the respiratory nitrous‐oxide reductase from Paracoccus denitrificans

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