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Dual targeted mitochondrial proteins are characterized by lower MTS parameters and total net charge.

Dinur-Mills M, Tal M, Pines O - PLoS ONE (2008)

Bottom Line: Mitochondrial proteins were considered dual-targeted if they were also found or predicted to be localized to the cytosol, the nucleus, the endoplasmic reticulum (ER) or the peroxisome.We found that dual localized mitochondrial proteins have i) A weaker mitochondrial targeting sequence (MitoProtII score, hydrophobic moment and number of basic residues) and ii) a lower whole-protein net charge, when compared to exclusive mitochondrial proteins.Taken together, these results establish dual targeting as a widely abundant phenomenon that should affect our concepts of gene expression and protein function.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, Hebrew University Medical School, Jerusalem, Israel.

ABSTRACT

Background: In eukaryotic cells, identical proteins can be located in different subcellular compartments (termed dual-targeted proteins).

Methodology/principal findings: We divided a reference set of mitochondrial proteins (published single gene studies) into two groups: i) Dual targeted mitochondrial proteins and ii) Exclusive mitochondrial proteins. Mitochondrial proteins were considered dual-targeted if they were also found or predicted to be localized to the cytosol, the nucleus, the endoplasmic reticulum (ER) or the peroxisome. We found that dual localized mitochondrial proteins have i) A weaker mitochondrial targeting sequence (MitoProtII score, hydrophobic moment and number of basic residues) and ii) a lower whole-protein net charge, when compared to exclusive mitochondrial proteins. We have also generated an annotation list of dual-targeted proteins within the predicted yeast mitochondrial proteome. This considerably large group of dual-localized proteins comprises approximately one quarter of the predicted mitochondrial proteome. We supported this prediction by experimental verification of a subgroup of the predicted dual targeted proteins.

Conclusions/significance: Taken together, these results establish dual targeting as a widely abundant phenomenon that should affect our concepts of gene expression and protein function. Possible relationships between the MTS/mature sequence traits and protein dual targeting are discussed.

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Dual localized proteins of the mitochondrial reference set are enriched for proteins with a low MitoProtII score.Distribution of MitoProtII scores in dual localized (grey) and exclusive mitochondrial (white) proteins were analyzed using χ2 test. Statistically significant differences in specific categories according to the χ2 test (df = 1) are marked with asterisks (* p-value <0.05; ** p-value <0.005; *** p-value <0.001). Mitochondrial localization was determined according to the Mitop2 reference set.
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pone-0002161-g001: Dual localized proteins of the mitochondrial reference set are enriched for proteins with a low MitoProtII score.Distribution of MitoProtII scores in dual localized (grey) and exclusive mitochondrial (white) proteins were analyzed using χ2 test. Statistically significant differences in specific categories according to the χ2 test (df = 1) are marked with asterisks (* p-value <0.05; ** p-value <0.005; *** p-value <0.001). Mitochondrial localization was determined according to the Mitop2 reference set.

Mentions: We divided the two groups of the reference set above (dual targeted and exclusive) into subgroups of MitoProtII score intervals and examined the difference in their distribution. (Fig. 1; Table 2, χ2 test results). Dual-localized proteins are enriched for proteins harboring a weak MitoProtII score (<0.2), whereas, exclusive mitochondrial proteins are enriched in proteins harboring a strong MitoProtII scores (>0.7) (Apparent in Fig 1). This difference in distribution is statistically significant according to χ2 test (p-value = 0.009, Table 2).


Dual targeted mitochondrial proteins are characterized by lower MTS parameters and total net charge.

Dinur-Mills M, Tal M, Pines O - PLoS ONE (2008)

Dual localized proteins of the mitochondrial reference set are enriched for proteins with a low MitoProtII score.Distribution of MitoProtII scores in dual localized (grey) and exclusive mitochondrial (white) proteins were analyzed using χ2 test. Statistically significant differences in specific categories according to the χ2 test (df = 1) are marked with asterisks (* p-value <0.05; ** p-value <0.005; *** p-value <0.001). Mitochondrial localization was determined according to the Mitop2 reference set.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2367453&req=5

pone-0002161-g001: Dual localized proteins of the mitochondrial reference set are enriched for proteins with a low MitoProtII score.Distribution of MitoProtII scores in dual localized (grey) and exclusive mitochondrial (white) proteins were analyzed using χ2 test. Statistically significant differences in specific categories according to the χ2 test (df = 1) are marked with asterisks (* p-value <0.05; ** p-value <0.005; *** p-value <0.001). Mitochondrial localization was determined according to the Mitop2 reference set.
Mentions: We divided the two groups of the reference set above (dual targeted and exclusive) into subgroups of MitoProtII score intervals and examined the difference in their distribution. (Fig. 1; Table 2, χ2 test results). Dual-localized proteins are enriched for proteins harboring a weak MitoProtII score (<0.2), whereas, exclusive mitochondrial proteins are enriched in proteins harboring a strong MitoProtII scores (>0.7) (Apparent in Fig 1). This difference in distribution is statistically significant according to χ2 test (p-value = 0.009, Table 2).

Bottom Line: Mitochondrial proteins were considered dual-targeted if they were also found or predicted to be localized to the cytosol, the nucleus, the endoplasmic reticulum (ER) or the peroxisome.We found that dual localized mitochondrial proteins have i) A weaker mitochondrial targeting sequence (MitoProtII score, hydrophobic moment and number of basic residues) and ii) a lower whole-protein net charge, when compared to exclusive mitochondrial proteins.Taken together, these results establish dual targeting as a widely abundant phenomenon that should affect our concepts of gene expression and protein function.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, Hebrew University Medical School, Jerusalem, Israel.

ABSTRACT

Background: In eukaryotic cells, identical proteins can be located in different subcellular compartments (termed dual-targeted proteins).

Methodology/principal findings: We divided a reference set of mitochondrial proteins (published single gene studies) into two groups: i) Dual targeted mitochondrial proteins and ii) Exclusive mitochondrial proteins. Mitochondrial proteins were considered dual-targeted if they were also found or predicted to be localized to the cytosol, the nucleus, the endoplasmic reticulum (ER) or the peroxisome. We found that dual localized mitochondrial proteins have i) A weaker mitochondrial targeting sequence (MitoProtII score, hydrophobic moment and number of basic residues) and ii) a lower whole-protein net charge, when compared to exclusive mitochondrial proteins. We have also generated an annotation list of dual-targeted proteins within the predicted yeast mitochondrial proteome. This considerably large group of dual-localized proteins comprises approximately one quarter of the predicted mitochondrial proteome. We supported this prediction by experimental verification of a subgroup of the predicted dual targeted proteins.

Conclusions/significance: Taken together, these results establish dual targeting as a widely abundant phenomenon that should affect our concepts of gene expression and protein function. Possible relationships between the MTS/mature sequence traits and protein dual targeting are discussed.

Show MeSH