Pir1p Mediates Translocation of the Yeast Apn1p Endonuclease into the Mitochondria To Maintain Genomic Stability

Vongsamphanh, Ratsavarinh; Fortier, Pierre-Karl; Ramotar, Dindial

doi:10.1128/mcb.21.5.1647-1655.2001

Cited by 92 publications

(66 citation statements)

References 50 publications

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“…Pir1, an O-glycosylated protein required for yeast cell wall stability, was found to mask the NLS of Apn1 and also plays an active role in the mitochondrial targeting of the protein. Thus, the predicted N-terminal MTS of Apn1 is not sufficient for mitochondrial targeting in the absence of Pir1 (27). Because we could not get an accurate crystal structure of the C terminus of APE1, we then hypothesized that another possible mechanism of APE1 conditional mitochondrial targeting could be that the putative MTS of APE1 needs assistance to conduct the protein into the mitochondria by some protein chaperones that are induced by oxidative stress.…”

Section: Discussionmentioning

confidence: 98%

“…The most noteworthy sites are Lys 299 , Arg 301 , and Lys 303 , insofar as their replacement with alanine diminished the affinities of peptide to Tom20. Interestingly, the replacement of residues Lys 24 , Lys 25 , Lys 27 , and Lys 31 enhanced the affinities to Tom20. Because they are located in the N terminus of APE1, it is possible that these particular lysine residues function as suppressors to prevent the distribution of APE1 to the mitochondrion.…”

Section: Discussionmentioning

confidence: 99%

“…3B) just slightly reduced the affinities to Tom20cd. Surprisingly, the alanine mutation at residues Lys 24 , Lys 25 , Lys 27 , and Lys 31 even enhanced the peptide binding efficacy to Tom20cd (Fig. 3C).…”

Section: Alanine Replacement Of Three Positively Charged Amino Acids mentioning

confidence: 99%

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Identification and Characterization of Mitochondrial Targeting Sequence of Human Apurinic/Apyrimidinic Endonuclease 1

Zhong

Zhu

et al. 2010

Journal of Biological Chemistry

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Dually targeted mitochondrial proteins usually possess an unconventional mitochondrial targeting sequence (MTS), which makes them difficult to predict by current bioinformatics approaches. Human apurinic/apyrimidinic endonuclease (APE1) plays a central role in the cellular response to oxidative stress. It is a dually targeted protein preferentially residing in the nucleus with conditional distribution in the mitochondria. However, the mitochondrial translocation mechanism of APE1 is not well characterized because it harbors an unconventional MTS that is difficult to predict by bioinformatics analysis. Two experimental approaches were combined in this study to identify the MTS of APE1. First, the interactions between the peptides from APE1 and the three purified translocase receptors of the outer mitochondrial membrane (Tom) were evaluated using a peptide array screen. Consequently, the intracellular distribution of green fluorescent protein-tagged, truncated, or mutated APE1 proteins was traced by tag detection. The results demonstrated that the only MTS of APE1 is harbored within residues 289 -318 in the C terminus, which is normally masked by the intact N-terminal structure. As a dually targeted mitochondrial protein, APE1 possesses a special distribution pattern of different subcellular targeting signals, the identification of which sheds light on future prediction of MTSs.Human APE1 (apurinic/apyrimidinic endonuclease) is an important multifunctional protein that plays a central role in the cellular response to oxidative stress. The two major activities of APE1 are DNA repair and redox regulation of transcriptional factors. On one hand, APE1 functions as a critical ratelimiting enzyme in DNA base excision repair and accounts for nearly all of the AP site incision activities in cell extracts (1). On the other hand, APE1 also exerts unique redox activity to regulate the DNA binding affinity of certain transcriptional factors by controlling the redox status of their DNA-binding domain (2). Inhibition of the redox function of APE1 blocks murine endothelial cell growth and angiogenesis and also blocks the growth of human tumor cell lines (3). The biological importance of APE1 is highlighted by the finding that APE1 knockout mice exhibit an embryonic lethal phenotype (4). Although APE1 has long been labeled as a nuclear protein, a growing body of evidence has shown that the subcellular distribution of APE1 can be cytoplasmic in some cell types with high metabolic or proliferative rates, with predominant localization in the mitochondria and the endoplasmic reticulum (5-7). Recent mitochondrial proteomic studies have further confirmed the existence of APE1 in the mitochondria (8). Considering the importance of the mitochondria in cellular response to oxidative stress, the roles of APE1 in the mitochondria have been extensively investigated.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Identification and Characterization of Mitochondrial Targeting Sequence of Human Apurinic/Apyrimidinic Endonuclease 1

Zhong

Zhu

et al. 2010

Journal of Biological Chemistry

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“…Such dual localization of a protein possessing both nuclear and mitochondria-targeting sequences was recently reported for several proteins, including the human RNA helicase MDDX28 (41) and the yeast protein Nfs1p (42). Another interesting example is the yeast repair enzyme Apn1p that apparently possesses a mitochondrial as well as a nuclear localization sequence; in this case, targeting of the enzyme to mitochondria is enhanced by another protein that interferes with nuclear transport of Apn1p (43).…”

Section: Discussionmentioning

confidence: 99%

Dual localization of human DNA topoisomerase IIIα to mitochondria and nucleus

Wang

Lyu

Wang

2002

Proc. Natl. Acad. Sci. U.S.A.

106

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The human TOP3␣ gene encoding DNA topoisomerase III␣ (hTop3␣) has two potential start codons for the synthesis of proteins 1,001 and 976 aa residues in length. The sequence of the N-terminal region of the 1,001-residue form resembles signal peptide sequences for mitochondrial import, and fluorescence microscopy shows that the addition of as few as the first 34 aa of the 1,001-residue form of hTop3␣ to a green fluorescent protein can direct the chimeric protein to mitochondria. Biochemical analyses of subcellular fractions of HeLa cells further demonstrate that a distinctive fraction of hTop3␣ is present inside mitochondria, as evidenced by its resistance to proteinase K. This fraction constitutes several percent of the enzyme in the nuclear fraction, suggesting that the distribution of the mitochondrial and nuclear forms of hTop3␣ is roughly in proportion to the DNA contents of these cellular compartments. The presence of a type IA DNA topoisomerase in the mitochondria of other eukaryotes is supported by an examination of the amino acid sequences of mouse and Drosophila DNA topoisomerase III␣ and Schizosaccharomyces pombe DNA topoisomerase III. Given the presence of at least one type IA DNA topoisomerase in all forms of life examined to date, the finding of a type IA enzyme in mitochondria further supports the notion of a key role of such enzymes in DNA transactions.

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“…This pathway is well studied in the nucleus of many organisms, and isoforms of several key components have been shown to localize to the mitochondrial compartment (Rosenquist et al 1997;You et al 1999;Vongsamphanh et al 2001). However, despite their extensive nuclear and biochemical characterization, the role of these isoforms in the repair of mtDNA is poorly understood.…”

Section: Epletion Of Mitochondrial Function Has Beenmentioning

confidence: 99%

Evidence That Msh1p Plays Multiple Roles in Mitochondrial Base Excision Repair

2009

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Mitochondrial DNA is thought to be especially prone to oxidative damage by reactive oxygen species generated through electron transport during cellular respiration. This damage is mitigated primarily by the base excision repair (BER) pathway, one of the few DNA repair pathways with confirmed activity on mitochondrial DNA. Through genetic epistasis analysis of the yeast Saccharomyces cerevisiae, we examined the genetic interaction between each of the BER proteins previously shown to localize to the mitochondria. In addition, we describe a series of genetic interactions between BER components and the MutS homolog MSH1, a respiration-essential gene. We show that, in addition to their variable effects on mitochondrial function, mutant msh1 alleles conferring partial function interact genetically at different points in mitochondrial BER. In addition to this separation of function, we also found that the role of Msh1p in BER is unlikely to be involved in the avoidance of large-scale deletions and rearrangements.

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Pir1p Mediates Translocation of the Yeast Apn1p Endonuclease into the Mitochondria To Maintain Genomic Stability

Cited by 92 publications

References 50 publications

Identification and Characterization of Mitochondrial Targeting Sequence of Human Apurinic/Apyrimidinic Endonuclease 1

Identification and Characterization of Mitochondrial Targeting Sequence of Human Apurinic/Apyrimidinic Endonuclease 1

Dual localization of human DNA topoisomerase IIIα to mitochondria and nucleus

Evidence That Msh1p Plays Multiple Roles in Mitochondrial Base Excision Repair

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