Degradation of Yeast Cytochromes c Dependent and Independent on Its Physiological Partners

Pearce, David A.; Sherman, Fred

doi:10.1006/abbi.1998.0591

Cited by 4 publications

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“…Wei and Sherman (2004) recently reported that SUE1 encodes a mitochondrial protein that is required for the efficient degradation of various mutationally altered forms of iso‐1 and iso‐2‐cytochrome c (iso‐2). There is a class of labile iso‐cytochromes c that are significantly protected from degradation by the presence of cytochromes a · a 3 and c 1 , the physiological partners of cytochrome c (Downie et al , 1977; Pearce and Sherman, 1995, 1997, 1998). The pathway responsible for degrading iso‐1 has been designated the RDD (rho‐dependent degradation) pathway (Wei et al , 2004; Chen et al , 2005).…”

Section: Introductionmentioning

confidence: 99%

Phenotypes of yeast mutants lacking the mitochondrial protein Pet20p

Polevoda

Panciera

Brown

et al. 2006

Yeast

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The pet20-delta deletion in Saccharomyces cerevisiae causes diminished growth on media containing non-fermentable carbon sources when incubated at both above and below the 30 degrees C optimal growth temperature. Furthermore, the pet20-delta strain has a greatly reduced level of cytochrome c, especially at 37 degrees C. The pet20-delta strain was sensitive to high NaCl and CaCl2 concentrations, hydrogen peroxide, oligomycin, polymixin B, amphotericin B and fluconazole. Biochemical fractionation and immunofluorescence staining demonstrated that Pet20p is located primarily in the mitochondria. Rhodamine B staining of pet20-delta cells showed an altered mitochondrial staining, indicating the possible lack of the mitochondrial membrane potential. We suggest that PET20 encodes a protein required for proper assembly or maintenance of mitochondrial components, but does not serve an enzymatic role. It is also possible that Pet20p may constitute a non-catalytic subunit of an uncharacterized mitochondrial complex or serve as a transporter or a coupling factor.

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Section: Introductionmentioning

confidence: 99%

Phenotypes of yeast mutants lacking the mitochondrial protein Pet20p

Polevoda

Panciera

Brown

et al. 2006

Yeast

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“…does not have diminished levels in Ϫ strains (15,17). ADD, containing amphipathic structures in the N-terminal region, also does not have diminished levels in Ϫ strains.…”

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confidence: 86%

“…Strain B-14705 with pAB2936 or pAB2937 was selected on plates of synthetic dropout medium/Ura Ϫ . Determination of holo-1 Content-holo-1 levels in intact cells were screened by the benzidine staining method (17) and examined visually with a spectroscope as described by Sherman and Slonimski (27). More accurate estimation was performed by the method of low temperature (Ϫ196°C) spectrophotometric recording with a modified Aviv Model 14DS spectrophotometer as described by Hickey et al (28).…”

Section: Construction Of the C-terminal Green Fluorescent Protein (Gfmentioning

confidence: 99%

“…The introduction of the global suppressor N52I (18) into both RDD and LDD holo-1 partially restores the levels of RDD holo-1 in Ϫ strains (17) and gives rise to better growth on a non-fermentable carbon source for LDD holo-1 in ϩ strains (17). Moreover, Pearce and Sherman (15) demonstrated that the absence of either cytochrome aa 3 or cytochrome c 1 , the physiological partner of cytochrome c in the IMS of mitochondria, causes increased sensitivity of RDD holo-1 to degradation.…”

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“…Subsequently, Pearce and Sherman (15,17) generated equivalent mutants of holo-1 and showed that amino acid replacements at several positions of holo-1 diminish the levels of holo-1, preferentially in Ϫ strains. This phenomenon is referred to as the Ϫ -dependent degradation (RDD) phenotype.…”

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Sue1p Is Required for Degradation of Labile Forms of Altered Cytochromes c in Yeast Mitochondria

Wei¹,

Sherman

2004

Journal of Biological Chemistry

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Previous studies on certain altered holo-isocytochromes c revealed a ؊ -dependent degradation (RDD) phenotype, in which certain altered holo-iso-1-cytochromes c are at normal or nearly normal levels in ؉ strains, but are at low levels or absent in ؊ strains, although wild-type holo-iso-1-cytochrome c is present at normal levels in both ؉ and related ؊ strains. The diminished levels of altered holo-iso-1-cytochrome c are due to the rapid degradation that is carried out by a novel proteolytic pathway in the IMS of mitochondria. SUE1, a nuclear gene that encodes a mitochondrial protein, was identified with a genetic screen for mutants that diminish RDD. The levels of RDD and certain other types of altered holo-iso-1-cytochrome c were elevated in ؊ sue1 strains. Also, ؉ sue1 strains containing certain altered holo-iso-1-cytochromes c grew better on non-fermentable carbon sources than the corresponding ؉ SUE1 strains. These results indicate that Sue1p may play an important role in the degradation of abnormal holo-iso-1-cytochrome c in the mitochondria.Intracellular proteolysis plays an important role in maintaining the integrity of the proper folded state of proteins. It ensures removal of damaged and misfolded polypeptides because they are prone to aggregation. A basic mechanism for control of protein degradation is compartmentalization (1). In eukaryotic cells, proteases have been detected in four compartments: the cytoplasm, nucleus, lysosome, and mitochondrion. The mitochondria have various subcompartments that possess ATP-dependent proteases as a quality control system for selectively removing unassembled or misfolded polypeptides. Several ATP-dependent proteases such as the Pim1 protease in the matrix or AAA (ATPases associated with a variety of cellular activities) proteases in the inner membrane of mitochondria have been identified (2-5).Additional proteolytic pathways may exist in the other two subcompartments of mitochondria: the intermembrane space (IMS) 1 and outer membrane. The existence of an ATP-dependent proteolytic activity in the mitochondrial IMS in mammals has been reported, although the ATP-dependent protease so far has not been identified (6, 7). We report herein a proteolytic pathway in the IMS of mitochondria acting on certain altered holo-iso-1-cytochromes c (holo-1) of the yeast Saccharomyces cerevisiae. S. cerevisiae contains two forms of cytochrome c, iso-1-cytochrome c (iso-1) and iso-2-cytochrome c (iso-2), which are encoded by the nuclear genes CYC1 and CYC7, which normally compose 95 and 5% of total cytochrome c, respectively, in aerobically grown, derepressed cells (8) and which are 80% identical. The isocytochromes c are synthesized in the cytosol as apocytochromes c and subsequently imported into mitochondria. Heme is covalently attached to the apocytochromes c by cytochrome c heme lyase, which is encoded by the gene CYC3, resulting in the formation of the mature holocytochromes c (9). Import of the apocytochromes c is dependent on the action of cytochrome c heme lyase, and cyc3-⌬ m...

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Enhanced mitochondrial degradation of yeast cytochrome c with amphipathic structures

et al. 2004

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The dispensable N-terminus of iso-1-cytochrome c (iso-1) in the yeast Saccharomyces cerevisiae was replaced by 11 different amphipathic structures. Rapid degradation of the corresponding iso-1 occurred, with the degree of degradation increasing with the amphipathic moments; and this amphipathic-dependent degradation was designated ADD. ADD occurred with the holo-forms in the mitochondria but not as the apo-forms in the cytosol. The extreme mutant type degraded with a half-life of approximately 12 min, whereas the normal iso-1 was stable over hours. ADD was influenced by the rho+/rho- state and by numerous chromosomal genes. Most importantly, ADD appeared to be specifically suppressed to various extents by deletions of any of the YME1, AFG3, or RCA1 genes encoding membrane-associated mitochondrial proteases, probably because the amphipathic structures caused a stronger association with the mitochondrial inner membrane and its associated proteases. The use of ADD assisted in the differentiation of substrates of different mitochondrial degradation pathways.

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Degradation of Yeast Cytochromes c Dependent and Independent on Its Physiological Partners

Cited by 4 publications

References 43 publications

Phenotypes of yeast mutants lacking the mitochondrial protein Pet20p

Phenotypes of yeast mutants lacking the mitochondrial protein Pet20p

Sue1p Is Required for Degradation of Labile Forms of Altered Cytochromes c in Yeast Mitochondria

Enhanced mitochondrial degradation of yeast cytochrome c with amphipathic structures

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