Inactivation of the gene encoding the 11‐kDa subunit VIII of the ubiquinol–cytochrome‐<i>c</i> oxidoreductase in <i>Saccharomyces cerevisiae</i>

Maarse, Ammy C.; Haan, M. de; Schoppink, Peter J.; Berden, J.A.; Grivell, Leslie A.

doi:10.1111/j.1432-1033.1988.tb13870.x

Cited by 54 publications

(37 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was also reported for the QCR7' mutant of HR2 [20] where the low amount of cytochrome aa, was thought to be due to the growth of the null-strain on maltose. The fact that such a phenotype is not found in a QCR8' mutant [21] and, more important, in the TNT2 transformant, which is otherwise indistinguishable from the QCR7' mutant, may point to a more causal relation between the N-terminal part of the 14-kDa subunit and the level of cytochrome ua3.…”

Section: Construction Of C-terminal Deletion Mutantsmentioning

confidence: 99%

“…It was shown that the mutant lacked holo-cytochrome b and had severely reduced levels of the Rieske Fe-S protein and the 11-kDa subunit. From the phenotype of this QCR7' mutant and the similar phenotypes of the QCR8" mutant [21] and mutants lacking functional cytochrome b [Sl, it was concluded that the 14-kDa subunit, together with the 11-kDa subunit and cytochrome b, forms a pre-assembly complex which is sensitive to endogenous proteases until association with the protease-resistant subcomplex formed by the two core subunits has taken place. Since this association is prevented in the QCR7', the QCR8' and the cytochrome b mutants, the remainder of the cytochrome b subcomplex is degraded when either of these subunits is missing [22, 231. The pleiotropic effects, caused by the disruption of the QCR7 gene, preclude analysis of the possible mechanistic involvement of this subunit in the activity of the enzyme.…”

mentioning

confidence: 99%

See 1 more Smart Citation

The C‐terminus of the 14‐kDa subunit of ubiquinol‐cytochrome‐c oxidoreductase of the yeast Saccharomyces cerevisiae is involved in the assembly of a functional enzyme

Hemrika

Jong

Berden

et al. 1994

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

Disruption of QCR7, the gene encoding the 14-kDa subunit of ubiquinol-cytochrome-c oxidoreductase of the yeast Saccharomyces cerevisiae, results in an inactive enzyme which lacks holocytochrome b and has severely reduced levels of apo-cytochrome b, the Rieske Fe-S protein and the 11-kDa subunit [Schoppink, P. J., Berden, J. Eul: J. Biochem. 181, An episomal system was developed to study the effect on complex I11 of transformation of in vitro mutagenised QCR7 genes to a QCR7' mutant. Transformation of a gene ( T N T l ) in which the 12 C-terminal residues are replaced by 3 amino acids encoded by an oligonucleotide containing a stop codon in all three reading frames (STOP-oligonucleotide), only leads to partial complementation of the respiratory capacity of the yeast strain. The amounts of apo-cytochrome 6 , the Rieske Fe-S protein and the 11 -kDa subunit are reduced and enzymic activity, together with the amount of holo-cytochrome b, is lowered to about 40% of that of the wild type, indicating a normal turnover number of the mutant enzyme.Transformation of the QCR7" mutant with another gene (TNT2) encoding the first 96 residues of the 14-kDa subunit fused to 9 amino acids encoded by the STOP-oligonucleotide, leads to a phenotype almost indistinguishable from that of the QCR7" mutant.The role of the charged C-terminus of the 14-kDa (and the 11-kDa) subunit in the assembly of a functional complex 111 is discussed.Ubiquinol-cytochrome-c oxidoreductase (complex I11 or the be, complex) is an oligomeric respiratory-chain enzyme, which invariably consists of at least three subunits: cytochrome b, cytochrome c, and the Rieske Fe-S subunit. These subunits, which carry the prosthetic groups, are functionally well characterised and have been shown to be essential for the activity of the enzyme. Fully active three-subunit be, complexes can be isolated from bacteria such as Paracoccus denitrficans and Rhodospirillum rubrum [1, 21. All known eukaryotic bc, complexes contain additional subunits, implying a more complicated situation in these cases, but in spite of a great deal of experimental effort the precise physiological role of these extra subunits remains enigmatic ( [ 3 , 41 and references therein). The bc, complex of the yeast Saccharomyces cerevisiae contains six or seven additional subunits which are named, in order of descending molecular mass the 44-, 40-(also called core I and core I1 subunits), 17-,

show abstract

Section: Construction Of C-terminal Deletion Mutantsmentioning

confidence: 99%

mentioning

confidence: 99%

The C‐terminus of the 14‐kDa subunit of ubiquinol‐cytochrome‐c oxidoreductase of the yeast Saccharomyces cerevisiae is involved in the assembly of a functional enzyme

Hemrika

Jong

Berden

et al. 1994

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…A 2478-bp HpaI-SmaI fragment from pUC18 : :M/M23(LEU2) was isolated to transform the mim23 mutants with the LEV2 gene flanked by 5'-noncoding sequences of MIM23. pUCl8 : :MIM23(LEU2) was constructed by cloning a 911-bp PstI fragment of YEpIacl81 ::MIM23 (containing a 1.6-kb SphI fragment harbouring the MIM23 gene [15]) into the PstI site of pUC18 and subsequent insertion of a 1974-bp HpaI-SaZI blunted LEU2 fragment from construct 6 [33] into the blunted SplI site of MIM23, 361-bp upstream of the start codon of MIM23 [15]. were isolated by lysis of the yeast cells with glass beads in breaking buffer and differential centrifugation, as described [36].…”

Section: Methodsmentioning

confidence: 99%

Functional and Physical Interactions of Components of the Yeast Mitochondrial Inner‐Membrane Import Machinery (MIM)

Blom¹,

Dekker²,

Meijer³

1995

European Journal of Biochemistry

View full text Add to dashboard Cite

The essential mitochondrial inner-membrane protein, Mim44, is involved in the translocation of preproteins across the mitochondrial inner membrane. Two other putative components of this protein-translocation system are the integral inner-membrane proteins, Mim23 and Miml7. Here, we present genetic evidence for functional co-operation of all three proteins. Furthermore, we show that Mim23 and Miml7 are associated in a protein complex that also contains two proteins of 55 kDa and 20 kDa. We speculate that this subcomplex forms the proteinaceous import channel of the inner-membrane which transiently interacts with a less abundant peripheral complex of Mim44 and mitochondrial heat-shock protein Hsp70.Keywords : mitochondrial inner membrane ; protein import.The majority of mitochondrial proteins are nuclear encoded and synthesized as preproteins on cytosolic ribosomes. The preproteins are imported into the mitochondrial matrix by independent proteinaceous translocation machineries in the mitochondrial outer and inner membranes. At least six proteins are members of the protein-translocation apparatus in the mitochondrial outer membrane in Neurosporu crussu [l-61 and Sacchuromyces cerevisiae [7 -1 I].Recent genetic and biochemical studies have identified three mitochondrial inner-membrane proteins, Mim44/Isp45 Mim23Mas6p [15, as putative components of the inner-membrane protein-import system. Their involvement in preprotein import was indicated by crosslinking to a precursor protein spanning both mitochondrial membranes 113, 18, 20, 211 and by accumulation of unprocessed precursor proteins after depletion of any of the three proteins in vivo [12,16, 191. The role of the peripheral inner-membrane protein, Mim44, in translocation of preproteins is further indicated by (a) its preferential interaction with preproteins with a complete presequence [20], (b) inhibition of protein import into mitoplasts by Mim44 antiserum [13], and (c) biochemical and genetic evidence for an interaction with mitochondrial matrix heat-shock protein Hsp70 (mt-Hsp70), which has an established function in driving protein translocation [22-261. Mim44 physically interacts with 10-20 % mt-Hsp70, and this reversible association is controlled by ATP and preproteins.Miml7 and Mim23 are both integral inner-membrane proteins and have significant sequence similarity in a region that contains putative membrane-spanning segments [ nel of the inner-membrane [27], but no physical interaction has been shown so far.Here, we present genetic evidence for a functional interaction of the preprotein-binding factor Mim44 with both Miml7 and Mim23. Furthermore, we show that Miml7 and Mim23 functionally and physically interact in a complex of proteins which also contains two proteins of 55 kDa and 20 kDa. We postulate that the mitochondrial inner-membrane import machinery may consist of two subcomplexes; a channel-forming core complex consisting of at least Miml7, Mim23, a 55-kDa protein and a 20-kDa protein, and a preprotein-binding complex formed by Mim44 and mt-...

show abstract

“…6). For example, the absence of the supernumerary subunits Qcr7p or Qcr8p (7,8) leads to a complete respiratory deficiency at any temperature, whereas Qcr6p or Qcr9p appears to be essential only at 36°C (9,10). The precise role of these supernumerary subunits and the nature of the functional interactions existing between them and the catalytic subunits still remain to be elucidated.…”

mentioning

confidence: 99%

A Pathogenic Cytochrome b Mutation Reveals New Interactions between Subunits of the Mitochondrial bc1Complex

Saint-Georges¹,

Bonnefoy²,

Rago³

et al. 2002

Journal of Biological Chemistry

View full text Add to dashboard Cite

Energy transduction in mitochondria involves five oligomeric complexes embedded within the inner membrane. They are composed of catalytic and noncatalytic subunits, the role of these latter proteins often being difficult to assign. One of these complexes, the bc1 complex, is composed of three catalytic subunits including cytochrome b and seven or eight noncatalytic subunits. Recently, several mutations in the human cytochrome b gene have been linked to various diseases. We have studied in detail the effects of a cardiomyopathy generating mutation G252D in yeast. This mutation disturbs the biogenesis of the bc1 complex at 36°C and decreases the steady-state level of the noncatalytic subunit Qcr9p. In addition, the G252D mutation and the deletion of QCR9 show synergetic defects that can be partially bypassed by suppressor mutations at position 252 and by a new cytochrome b mutation, P174T. Altogether, our results suggest that the supernumerary subunit Qcr9p enhances or stabilizes the interactions between the catalytic subunits, this role being essential at high temperature.Numerous cellular functions are performed by oligomeric complexes composed of catalytic and noncatalytic subunits and the role of these latter proteins is often difficult to assign. Energy transduction in mitochondria involves five oligomeric complexes that are embedded within the inner membrane. One of these complexes, the bc1 complex is composed of three catalytic and seven or eight noncatalytic subunits (for review, see Ref. 1). The three catalytic subunits, cytochrome b, cytochrome c1, and the Rieske iron-sulfur protein (Rieske) are conserved in the bacterial equivalents of this complex. However, several noncatalytic subunits are present in the mitochondrial bc1 complexes and are often referred to as supernumerary subunits although some are required for the enzymatic activity. In Saccharomyces cerevisiae the bc1 complex contains seven supernumerary subunits that are conserved in the mammalian enzyme. The mammalian bc1 complex presents an additional subunit that has no equivalent in yeast. The mitochondrial bc1 complexes from bovine, chicken, and yeast have been crystallized (2-5) and an analysis of these structures reveals that the general shape, size, and topology of the complexes are similar in the three organisms.

show abstract

Inactivation of the gene encoding the 11‐kDa subunit VIII of the ubiquinol–cytochrome‐c oxidoreductase in Saccharomyces cerevisiae

Cited by 54 publications

References 27 publications

The C‐terminus of the 14‐kDa subunit of ubiquinol‐cytochrome‐c oxidoreductase of the yeast Saccharomyces cerevisiae is involved in the assembly of a functional enzyme

The C‐terminus of the 14‐kDa subunit of ubiquinol‐cytochrome‐c oxidoreductase of the yeast Saccharomyces cerevisiae is involved in the assembly of a functional enzyme

Functional and Physical Interactions of Components of the Yeast Mitochondrial Inner‐Membrane Import Machinery (MIM)

A Pathogenic Cytochrome b Mutation Reveals New Interactions between Subunits of the Mitochondrial bc1Complex

Contact Info

Product

Resources

About