A Role for Pet100p in the Assembly of Yeast Cytochrome c Oxidase

Church, Cynthia; Goehring, Bradley; Forsha, Daniel; Wazny, P.; Poyton, Robert O.

doi:10.1074/jbc.m410726200

Cited by 37 publications

(18 citation statements)

References 62 publications

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“…In the absence of Cox25, Cox5 accumulation is significantly lowered, suggesting a role for Cox25 in the stability of this subunit. COX assembly is thought to be a sequential process (32,33) initiated by the synthesis of Cox1, which subsequently forms a subassembly with Cox5 and Cox6 (33,34). These subunits are in direct contact with Cox1 in the mature enzyme (35).…”

Section: Discussionmentioning

confidence: 99%

Cox25 Teams Up with Mss51, Ssc1, and Cox14 to Regulate Mitochondrial Cytochrome c Oxidase Subunit 1 Expression and Assembly in Saccharomyces cerevisiae

Fontanesi¹,

Clemente

Barrientos

2011

Journal of Biological Chemistry

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In the yeast Saccharomyces cerevisiae, mitochondrial cytochrome c oxidase (COX) biogenesis is translationally regulated. Mss51, a specific COX1 mRNA translational activator and Cox1 chaperone, drives the regulatory mechanism. During translation and post-translationally, newly synthesized Cox1 physically interacts with a complex of proteins involving Ssc1, Mss51, and Cox14, which eventually hand over Cox1 to the assembly pathway. This step is probably catalyzed by assembly chaperones such as Shy1 in a process coupled to the release of Ssc1-Mss51 from the complex. Impaired COX assembly results in the trapping of Mss51 in the complex, thus limiting its availability for COX1 mRNA translation. An exception is a null mutation in COX14 that does not affect Cox1 synthesis because the Mss51 trapping complexes become unstable, and Mss51 is readily available for translation. Here we present evidence showing that Cox25 is a new essential COX assembly factor that plays some roles similar to Cox14. A null mutation in COX25 by itself or in combination with other COX mutations does not affect Cox1 synthesis. Cox25 is an inner mitochondrial membrane intrinsic protein with a hydrophilic C terminus protruding into the matrix. Cox25 is an essential component of the complexes containing newly synthesized Cox1, Ssc1, Mss51, and Cox14. In addition, Cox25 is also found to interact with Shy1 and Cox5 in a complex that does not contain Mss51. These results suggest that once Ssc1-Mss51 are released from the Cox1 stabilization complex, Cox25 continues to interact with Cox14 and Cox1 to facilitate the formation of multisubunit COX assembly intermediates.

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Section: Discussionmentioning

confidence: 99%

Cox25 Teams Up with Mss51, Ssc1, and Cox14 to Regulate Mitochondrial Cytochrome c Oxidase Subunit 1 Expression and Assembly in Saccharomyces cerevisiae

Fontanesi¹,

Clemente

Barrientos

2011

Journal of Biological Chemistry

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“…The study of assembly intermediates in yeast has been less productive since they do not seem to accumulate in detectable amounts in most COX defective strains [31], probably due to the marked downregulation of Cox1 synthesis in the absence of fully assembled COX [32]. However, subassemblies have been detected in yeast cox2 [33] and pet100 mutants [34] and are similar to those observed in mammalian cells. Adding to the concept of linear assembly, it is known that the biogenesis of the membrane forms of at least the two major catalytic core subunits 1 and 2 follow relatively independent lines with the participation of subunit-specific chaperones (Figure 1 and reviewed in [8, 10],).…”

Section: More Than Fifty Years Of Eukaryotic Cytochrome C Oxidase mentioning

confidence: 99%

Biogenesis and assembly of eukaryotic cytochrome c oxidase catalytic core

Soto

Fontanesi

Liu

et al. 2012

Biochimica et Biophysica Acta (BBA) - Bioenergetics

200

210

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Eukaryotic cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. COX is a multimeric enzyme formed by subunits of dual genetic origin which assembly is intricate and highly regulated. The COX catalytic core is formed by three mitochondrial DNA encoded subunits, Cox1, Cox2 and Cox3, conserved in the bacterial enzyme. Their biogenesis requires the action of messenger-specific and subunit-specific factors which facilitate the synthesis, membrane insertion, maturation or assembly of the core subunits. The study of yeast strains and human cell lines from patients carrying mutations in structural subunits and COX assembly factors has been invaluable to identify these ancillary factors. Here we review the current state of knowledge of the biogenesis and assembly of the eukaryotic COX catalytic core and discuss the degree of conservation of the players and mechanisms operating from yeast to human.

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“…Pet100p is an integral inner membrane protein, whereas COX IV is a peripheral protein subunit that binds holocytochrome c oxidase on the matrix side of the inner membrane (32,33). The assembled form of COX IV is located at the inner membrane, whereas the unassembled form is located in the matrix (34). From Fig.…”

Section: Fig 1 Expression Of Yhb In Rhomentioning

confidence: 99%

Yeast Flavohemoglobin, a Nitric Oxide Oxidoreductase, Is Located in Both the Cytosol and the Mitochondrial Matrix

Cassanova

O’Brien²,

Stahl

et al. 2005

Journal of Biological Chemistry

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Yeast flavohemoglobin, YHb, encoded by the nuclear gene YHB1, has been implicated in both the oxidative and nitrosative stress responses in Saccharomyces cerevisiae. Previous studies have shown that the expression of YHB1 is optimal under normoxic or hyperoxic conditions, yet respiring yeast cells have low levels of reduced YHb pigment as detected by carbon monoxide (CO) photolysis difference spectroscopy of glucose-reduced cells. Here, we have addressed this apparent discrepancy by determining the intracellular location of the YHb protein and analyzing the relationships between respiration, YHb level, and intracellular location. We have found that although intact respiration-proficient cells lack a YHb CO spectral signature, cell extracts from these cells have both a YHb CO spectral signature and nitric oxide (NO) consuming activity. This suggests either that YHb cannot be reduced in vivo or that YHb heme is maintained in an oxidized state in respiring cells. By using an anti-YHb antibody and CO difference spectroscopy and by measuring NO consumption, we have found that YHb localizes to two distinct intracellular compartments in respiring cells, the mitochondrial matrix and the cytosol. Moreover, we have found that the distribution of YHb between these two compartments is affected by the presence or absence of oxygen and by the mitochondrial genome. The findings suggest that YHb functions in oxidative stress indirectly by consuming NO, which inhibits mitochondrial respiration and leads to enhanced production of reactive oxygen species, and that cells can regulate intracellular distribution of YHb in accordance with this function.

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A Role for Pet100p in the Assembly of Yeast Cytochrome c Oxidase

Cited by 37 publications

References 62 publications

Cox25 Teams Up with Mss51, Ssc1, and Cox14 to Regulate Mitochondrial Cytochrome c Oxidase Subunit 1 Expression and Assembly in Saccharomyces cerevisiae

Cox25 Teams Up with Mss51, Ssc1, and Cox14 to Regulate Mitochondrial Cytochrome c Oxidase Subunit 1 Expression and Assembly in Saccharomyces cerevisiae

Biogenesis and assembly of eukaryotic cytochrome c oxidase catalytic core

Yeast Flavohemoglobin, a Nitric Oxide Oxidoreductase, Is Located in Both the Cytosol and the Mitochondrial Matrix

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