Cbp3–Cbp6 interacts with the yeast mitochondrial ribosomal tunnel exit and promotes cytochrome <i>b</i> synthesis and assembly

Gruschke, Steffi; Kehrein, Kirsten; Römpler, Katharina; Gröne, Kerstin; Israel, Lars; Imhof, Axel; Herrmann, Johannes M.; Ott, Martin

doi:10.1083/jcb.2011031321941c

Cited by 3 publications

(6 citation statements)

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“…Indeed, the binding of Cbp3 along with Cbp6 to cytochrome b is important to protect the newly synthesized polypeptide from proteolytic degradation and to promote its insertion into the inner mitochondrial membrane. This assembly step does possibly require Cbp4 factor that mediates the assembly of cytochrome b into a functional bc 1 complex [14]. The two-dimensional analysis of the ΔCOR1/ΔCOR2 deletion strain expressing Cor2-TAP showed a co-migration of the bc 1 early core and Cbp3 and Cbp4 (Fig.…”

Section: Discussionmentioning

confidence: 98%

“…4), according to their function in Cyt b maturation [12][13][14][15]. Indeed, the binding of Cbp3 along with Cbp6 to cytochrome b is important to protect the newly synthesized polypeptide from proteolytic degradation and to promote its insertion into the inner mitochondrial membrane.…”

Section: Discussionmentioning

confidence: 99%

“…Cbp6, a translational activator of Cyt b, and Cbp3, a bc 1 complex assembly factor, form a complex with the newly synthesized Cyt b at the mitochondrial ribosomal tunnel exit [12][13][14]. When the new polypeptide is released from the ribosome, the additional factor Cbp4 is also recruited to this complex that finally promotes the assembly of Cyt b in the functional bc 1 complex [13,15].…”

Section: Introductionmentioning

confidence: 99%

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The dimerization of the yeast cytochrome bc1 complex is an early event and is independent of Rip1

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Papa

Ferramosca

et al. 2015

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research

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In Saccharomyces cerevisiae the mature cytochrome bc1 complex exists as an obligate homo-dimer in which each monomer consists of ten distinct protein subunits inserted into or bound to the inner mitochondrial membrane. Among them, the Rieske iron-sulfur protein (Rip1), besides its catalytic role in electron transfer, may be implicated in the bc1 complex dimerization. Indeed, Rip1 has the globular domain containing the catalytic center in one monomer while the transmembrane helix interacts with the adjacent monomer. In addition, the lack of Rip1 leads to the accumulation of an immature bc1 intermediate, only loosely associated with cytochrome c oxidase. In this study we have investigated the biogenesis of the yeast cytochrome bc1 complex using epitope tagged proteins to purify native assembly intermediates. We showed that the dimerization process is an early event during bc1 complex biogenesis and that the presence of Rip1, differently from previous proposals, is not essential for this process. We also investigated the multi-step model of bc1 assembly thereby lending further support to the existence of bona fide subcomplexes during bc1 maturation in the inner mitochondrial membrane. Finally, a new model of cytochrome bc1 complex assembly, in which distinct intermediates sequentially interact during bc1 maturation, has been proposed.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The dimerization of the yeast cytochrome bc1 complex is an early event and is independent of Rip1

Conte

Papa

Ferramosca

et al. 2015

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research

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“…The antibody against protein A was obtained from Sigma. Isolation of mitochondria, northern blotting (Gruschke et al, 2011), step-gradient purification of isolated mitochondria (Meisinger et al, 2000), and quantitative mass spectrometry were performed as described. …”

Section: Miscellaneous Methodsmentioning

confidence: 99%

“…Recent work has demonstrated that translational activators coordinate mitochondrial and nuclear gene expression to facilitate biogenesis of the OXPHOS (Gruschke et al, 2012;Mick et al, 2011). In the case of cytochrome b biogenesis, this feedback loop involves binding of a translational activator complex to the ribosomal tunnel exit to enable efficient interaction of the newly synthesized protein with an assembly factor (Gruschke et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Organization of Mitochondrial Gene Expression in Two Distinct Ribosome-Containing Assemblies

et al. 2015

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Mitochondria contain their own genetic system that provides subunits of the complexes driving oxidative phosphorylation. A quarter of the mitochondrial proteome participates in gene expression, but how all these factors are orchestrated and spatially organized is currently unknown. Here, we established a method to purify and analyze native and intact complexes of mitochondrial ribosomes. Quantitative mass spectrometry revealed extensive interactions of ribosomes with factors involved in all the steps of posttranscriptional gene expression. These interactions result in large expressosome-like assemblies that we termed mitochondrial organization of gene expression (MIOREX) complexes. Superresolution microscopy revealed that most MIOREX complexes are evenly distributed throughout the mitochondrial network, whereas a subset is present as nucleoid-MIOREX complexes that unite the whole spectrum of organellar gene expression. Our work therefore provides a conceptual framework for the spatial organization of mitochondrial protein synthesis that likely developed to facilitate gene expression in the organelle.

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The INA complex facilitates assembly of the peripheral stalk of the mitochondrial F₁F_o‐ATP synthase

et al. 2014

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Mitochondrial F1Fo-ATP synthase generates the bulk of cellular ATP. This molecular machine assembles from nuclear- and mitochondria-encoded subunits. Whereas chaperones for formation of the matrix-exposed hexameric F1-ATPase core domain have been identified, insight into how the nuclear-encoded F1-domain assembles with the membrane-embedded Fo-region is lacking. Here we identified the INA complex (INAC) in the inner membrane of mitochondria as an assembly factor involved in this process. Ina22 and Ina17 are INAC constituents that physically associate with the F1-module and peripheral stalk, but not with the assembled F1Fo-ATP synthase. Our analyses show that loss of Ina22 and Ina17 specifically impairs formation of the peripheral stalk that connects the catalytic F1-module to the membrane embedded Fo-domain. We conclude that INAC represents a matrix-exposed inner membrane protein complex that facilitates peripheral stalk assembly and thus promotes a key step in the biogenesis of mitochondrial F1Fo-ATP synthase.

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Cbp3–Cbp6 interacts with the yeast mitochondrial ribosomal tunnel exit and promotes cytochrome b synthesis and assembly

Cited by 3 publications

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The dimerization of the yeast cytochrome bc1 complex is an early event and is independent of Rip1

The dimerization of the yeast cytochrome bc1 complex is an early event and is independent of Rip1

Organization of Mitochondrial Gene Expression in Two Distinct Ribosome-Containing Assemblies

The INA complex facilitates assembly of the peripheral stalk of the mitochondrial F₁F_o‐ATP synthase

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Cbp3–Cbp6 interacts with the yeast mitochondrial ribosomal tunnel exit and promotes cytochrome b synthesis and assembly

Cited by 3 publications

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The dimerization of the yeast cytochrome bc1 complex is an early event and is independent of Rip1

The dimerization of the yeast cytochrome bc1 complex is an early event and is independent of Rip1

Organization of Mitochondrial Gene Expression in Two Distinct Ribosome-Containing Assemblies

The INA complex facilitates assembly of the peripheral stalk of the mitochondrial F1Fo‐ATP synthase

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The INA complex facilitates assembly of the peripheral stalk of the mitochondrial F₁F_o‐ATP synthase