The Cbp3–Cbp6 complex coordinates cytochrome <i>b</i> synthesis with <i>bc1</i> complex assembly in yeast mitochondria

Gruschke, Steffi; Römpler, Katharina; Hildenbeutel, Markus; Kehrein, Kirsten; Kühl, Inge; Bonnefoy, Nathalie; Ott, Martin

doi:10.1083/jcb.201206040

Cited by 81 publications

(176 citation statements)

References 41 publications

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“…On the contrary, Cbp3 and Cbp6 form a heterodimer, which interacts with the mitochondrial ribosome exit tunnel even in the absence of COB mRNA (43). Therefore, they could act by promoting elongation of the nascent polypeptide, a possibility supported by the fact that they have been shown to interact with newly synthesized Cytb (11,43). However, translation of the ARG8 m reporter gene from the COB locus is dramatically decreased, though not abolished, in cbp3 and cbp6 null mutant strains (11,43).…”

Section: Translational Control Ofmentioning

confidence: 88%

“…Therefore, they could act by promoting elongation of the nascent polypeptide, a possibility supported by the fact that they have been shown to interact with newly synthesized Cytb (11,43). However, translation of the ARG8 m reporter gene from the COB locus is dramatically decreased, though not abolished, in cbp3 and cbp6 null mutant strains (11,43). As Cytb and Arg8 m share low-sequence similarity, it is unlikely that Cbp3 and Cbp6 function on the ARG8 m ORF.…”

Section: Translational Control Ofmentioning

confidence: 95%

“…Contrary to mutations in the four COB translational activators, the deletion of nuclear bc 1 complex structural subunits and assembly factors does not reduce the expression of the ARG8 m reporter gene from the COB locus (11). However, with the exception of mutants affecting the last step of bc 1 complex biogenesis (qrc9, qrc10, rip1, bcs1 and mzm1), Cytb synthesis is impaired to different degrees in these strains (11), suggesting that the assembly status of the enzyme could play an indirect role on COB mRNA translation.…”

Section: Translational Control Ofmentioning

confidence: 99%

“…At the beginning of the last decade, a CES mechanism was identified that translationally controls the expression of Cox1 in yeast mitochondria (8,9). More recently, translational regulation of Atp6, Atp8 and Cytb has been also reported (10,11).…”

Section: Figmentioning

confidence: 99%

“…Cytb also represents the cornerstone of bc 1 complex biogenesis, the anchor protein around which the enzyme is built by progressive sequential addition of all the other nucleus-encoded subunits. In particular, studies of the assembly intermediates that accumulate in yeast bc 1 -complex-deficient mutants (11,(47)(48)(49) have delineated a model of modular multistep assembly that starts with Cytb expression and insertion into the mitochondrial inner membrane (40). Briefly, an early assembly subcomplex is subsequently obtained by the addition of subunit Qcr7 and Qcr8, followed by incorporation of Cor1, Cor2, Qcr6 and Cyt1, to form a proteolytically protected late-assembly intermediate.…”

Section: Translational Control Ofmentioning

confidence: 99%

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Mechanisms of mitochondrial translational regulation

Fontanesi

2013

IUBMB Life

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The mitochondrial oxidative phosphorylation system is formed by multimeric enzymes. In the yeast Saccharomyces cerevisiae, the bc 1 complex, cytochrome c oxidase and the F 1 F O ATP synthase contain subunits of dual genetic origin. It has been recently established that key subunits of these enzymes, translated on mitochondrial ribosomes, are the subjects of assembly-dependent translational regulation. This type of control of gene expression plays a pivotal role in optimizing the biogenesis of mitochondrial respiratory membranes by coordinating protein synthesis and complex assembly and by limiting the accumulation of potentially harmful assembly intermediates. Here, the author will discuss the mechanisms governing translational regulation in yeast mitochondria in the light of the most recent discoveries in the field. V C 2013 IUBMB Life, 65(5): [397][398][399][400][401][402][403][404][405][406][407][408] 2013

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Section: Translational Control Ofmentioning

confidence: 88%

Section: Translational Control Ofmentioning

confidence: 95%

Section: Translational Control Ofmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Section: Translational Control Ofmentioning

confidence: 99%

See 3 more Smart Citations

Mechanisms of mitochondrial translational regulation

Fontanesi

2013

IUBMB Life

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Mitochondrial disorders of the OXPHOS system

2020

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Mitochondrial disorders are amongst the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase (also called complex V). The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by complex V to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namely the mitochondrial and nuclear DNA, to the coordinated assembly of components and cofactors building each individual complex and eventually the supercomplexes. The genetic cause underlying around half of the diagnosed mitochondrial disease cases is currently known. Many of these cases result from pathogenic variants in genes encoding structural subunits or additional factors directly involved in the assembly of the ETC complexes. Here we review the historical and most recent findings concerning the clinical phenotypes and the molecular pathological mechanisms underlying this particular group of disorders.

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Insights into conformational changes in cytochrome b during the early steps of its maturation

Carlström,

Ott

2024

FEBS Letters

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Membrane proteins carrying redox cofactors are key subunits of respiratory chain complexes, yet the exact path of their folding and maturation remains poorly understood. Here, using cryo‐EM and structure prediction via Alphafold2, we generated models of early assembly intermediates of cytochrome b (Cytb), a central subunit of complex III. The predicted structure of the first assembly intermediate suggests how the binding of Cytb to the assembly factor Cbp3‐Cbp6 imposes an open configuration to facilitate the acquisition of its heme cofactors. Moreover, structure predictions of the second intermediate indicate how hemes get stabilized by binding of the assembly factor Cbp4, with a concomitant weakening of the contact between Cbp3‐Cbp6 and Cytb, preparing for the release of the fully hemylated protein from the assembly factors.

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The Cbp3–Cbp6 complex coordinates cytochrome b synthesis with bc1 complex assembly in yeast mitochondria

Abstract: The Cbp3–Cbp6 complex, which has been shown previously to promote cytochrome b synthesis and assembly, plays a key role in adjusting cytochrome b expression to the efficiency of assembly of the respiratory chain bc1 complex.

Cited by 81 publications

References 41 publications

Mechanisms of mitochondrial translational regulation

Mechanisms of mitochondrial translational regulation

Mitochondrial disorders of the OXPHOS system

Insights into conformational changes in cytochrome b during the early steps of its maturation

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