Composition of complex I from Neurospora crassa and disruption of two “accessory” subunits

Marques, Isabel; Duarte, Margarida; Assunção, Joana; Ushakova, Alexandra V.; Videira, Arnaldo

doi:10.1016/j.bbabio.2004.12.003

Cited by 52 publications

(48 citation statements)

References 65 publications

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“…In silico analysis of the N. crassa genomic database (Neurospora Sequencing Project) led to the identification of the gene (NCU00278.5) encoding the 13.4L protein, which is a homologue of the described mammalian complex I assembly chaperone NDUFAF2 (20) and a paralog of the 13.4-kDa structural subunit of complex I (14). The single-copy gene is located on linkage group III of the fungal genome and comprises 2 exons.…”

Section: Resultsmentioning

confidence: 99%

“…Manipulation of N. crassa wild type strains 74-OR23-1A and 74-OR8-1a as well as of the complex I mutant strains nuo9.8 (24), nuo12.3 (25), nuo14 (14), nuo21 (26), nuo21.3a (27), nuo21.3c (28), nuo24 (17), nuo51 (18), and nuo78 (29) was performed according to standard procedures (30). The nuo13.4 (FGSC 13054a and FGSC 13055A), nuo18.4 (FGSC 15972a), and 13.4L (FGSC 11150a) mutant strains were obtained from the FGSC.…”

Section: Methodsmentioning

confidence: 99%

“…The Neurospora enzyme is composed of 43 different polypeptides (14), all of them displaying homologues in the mammalian complex (15). The characterization of mutant strains harboring disrupted complex I genes led to the outline of an assembly model, in which three membrane arm intermediates are assembled independently, two of them combining to originate the large membrane arm intermediate that joins with the small intermediate forming the membrane arm.…”

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confidence: 99%

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Novel Insights into the Role of Neurospora crassa NDUFAF2, an Evolutionarily Conserved Mitochondrial Complex I Assembly Factor

Pereira

Videira

Duarte

2013

Molecular and Cellular Biology

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bComplex I deficiency is commonly associated with mitochondrial oxidative phosphorylation diseases. Mutations in nuclear genes encoding structural subunits or assembly factors of complex I have been increasingly identified as the cause of the diseases. One such factor, NDUFAF2, is a paralog of the NDUFA12 structural subunit of the enzyme, but the mechanism by which it exerts its function remains unknown. Herein, we demonstrate that the Neurospora crassa NDUFAF2 homologue, the 13.4L protein, is a late assembly factor that associates with complex I assembly intermediates containing the membrane arm and the connecting part but lacking the N module of the enzyme. Furthermore, we provide evidence that dissociation of the assembly factor is dependent on the incorporation of the putative regulatory module composed of the subunits of 13.4 (NDUFA12), 18.4 (NDUFS6), and 21 (NDUFS4) kDa. Our results demonstrate that the 13.4L protein is a complex I assembly factor functionally conserved from fungi to mammals.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Novel Insights into the Role of Neurospora crassa NDUFAF2, an Evolutionarily Conserved Mitochondrial Complex I Assembly Factor

Pereira

Videira

Duarte

2013

Molecular and Cellular Biology

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“…The wild-type N. crassa sequenced strain FGSC2489 (Galagan et al, 2003) and the gene deletion strains generated by the Neurospora Genome Project (Colot et al, 2006) were obtained from the Fungal Genetics Stock Center (FGSC) (McCluskey, 2003). The complex I mutant nuo14 (Marques et al, 2005), the AMID (DNCU06061; FGSC12090) deletion strain (Castro et al, 2008) and the general handling of the fungal strains (Davis & de Serres, 1970) have been described before. For the determination of drug sensitivity in spot assays, conidia from different strains were harvested with distilled water and adjusted to a concentration of 6.56610 7 cells ml 21 .…”

Section: Methodsmentioning

confidence: 99%

Transcriptional analysis of the response of Neurospora crassa to phytosphingosine reveals links to mitochondrial function

et al. 2009

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Treatment of Neurospora crassa cells with phytosphingosine (PHS) induces programmed cell death (PCD) by an unknown mechanism. To determine the relationship between PHS treatment and PCD, we determined changes in global gene expression levels in N. crassa during a time-course of PHS treatment. Most genes having differential expression levels compared to untreated samples showed an increase in relative expression level upon PHS exposure. However, genes encoding mitochondrial proteins were highly enriched among~100 genes that showed a relative decrease in expression levels after PHS treatment, suggesting that repression of these genes might be related to the death-inducing effects of PHS. Since mutants in respiratory chain complex I are more resistant to both PHS and hydrogen peroxide (H 2 O 2 ) than the wild-type strain, possibly related to the production of reactive oxygen species, we also compared gene expression profiles of a complex I mutant (nuo14) and wild-type in response to H 2 O 2 . Genes with higher expression levels in the mutant, in the presence of H 2 O 2 , are also significantly enriched in genes encoding mitochondrial proteins. These data suggest that complex I mutants cope better with drug-induced decrease in expression of genes encoding mitochondrial proteins and may explain their increased resistance to both PHS and H 2 O 2 . As a way of identifying new components required for PHS-induced death, we analysed the PHS sensitivity of 24 strains carrying deletions in genes that showed a significant alteration in expression pattern when the wild-type was exposed to the sphingolipid. Two additional mutants showing increased resistance to PHS were identified and both encode predicted mitochondrial proteins, further supporting the role of the mitochondria in PHS-induced PCD. INTRODUCTIONIn response to endogenous or external stimuli, living cells can undergo a genetic programme eventually leading to death, commonly known as programmed cell death (PCD). This suicide process can take several forms (apoptosis, necrosis, autophagy), each of which displays typical characteristics at both the cellular and molecular level. These processes can be interchangeable and are sometimes difficult to distinguish. In metazoan organisms, the death programme is essential for development and its dysfunction may result in human disease, such as cancer. In addition to multicellular eukaryotic species, both prokaryotic and eukaryotic unicellular organisms also undergo PCD (Cheng et al., 2008;Green & Kroemer, 2004;Hamann et al., 2008;Madeo et al., 2004).Mitochondria are cellular organelles, still possessing their own genome, that are responsible for the production of most cellular energy in eukaryotes. This production occurs mainly in the mitochondrial inner membrane through the process of oxidative phosphorylation, which involves the components of the respiratory chain and ATP synthase (Hatefi, 1985). The involvement of mitochondria and specific mitochondrial proteins, particularly components of the respiratory chain, in most ca...

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“…However, it was reported that a defect in a membrane arm subunit could prevent the proper formation of the peripheral arm (60). In the dum20 mutant of C. reinhardtii, the loss of ND1 prevents the assembly of any complex (55).…”

Section: Restoration Of Nadh Oxidation By Complex I In Cmsnad7mentioning

confidence: 99%

Targeting the NAD7 Subunit to Mitochondria Restores a Functional Complex I and a Wild Type Phenotype in the Nicotiana sylvestris CMS II Mutant Lacking nad7

Pineau

Mathieu

Gérard-Hirne

et al. 2005

Journal of Biological Chemistry

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The mitochondrial DNA of the Nicotiana sylvestris CMSII mutant carries a 72-kb deletion comprising the single copy nad7 gene that encodes the NAD7 subunit of the respiratory complex I (NADH-ubiquinone oxidoreductase). CMSII plants lack rotenone-sensitive complex I activity and are impaired in physiological and phenotypical traits. To check whether these changes directly result from the deletion of nad7, we constructed CMS transgenic plants (termed as CMSnad7) carrying an edited nad7 cDNA fused to the CAMV 35 S promoter and to a mitochondrial targeting sequence. The nad7 sequence was transcribed and translated and the NAD7 protein directed to mitochondria in CMSnad7 transgenic plants, which recovered both wild type morphology and growth features. Blue-native/SDS gel electrophoresis and enzymatic assays showed that, whereas fully assembled complex I was absent from CMSII mitochondria, a functional complex was present in CMSnad7 mitochondria. Furthermore, a supercomplex involving complex I and complex III was present in CMSnad7 as in the wild type. Taken together, these data demonstrate that lack of complex I in CMSII was indeed the direct consequence of the absence of nad7. Hence, NAD7 is a key element for complex assembly in plants. These results also show that allotopic expression from the nucleus can fully complement the lack of a mitochondrialencoded complex I gene.

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Composition of complex I from Neurospora crassa and disruption of two “accessory” subunits

Cited by 52 publications

References 65 publications

Novel Insights into the Role of Neurospora crassa NDUFAF2, an Evolutionarily Conserved Mitochondrial Complex I Assembly Factor

Novel Insights into the Role of Neurospora crassa NDUFAF2, an Evolutionarily Conserved Mitochondrial Complex I Assembly Factor

Transcriptional analysis of the response of Neurospora crassa to phytosphingosine reveals links to mitochondrial function

Targeting the NAD7 Subunit to Mitochondria Restores a Functional Complex I and a Wild Type Phenotype in the Nicotiana sylvestris CMS II Mutant Lacking nad7

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