Metabolic effects of altering redundant targeting signals for yeast mitochondrial malate dehydrogenase

W. C. Small, L. McAlister-Henn

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Eukaryotic cells contain highly homologous isozymes of malate dehydrogenase which catalyze the same reaction in different cellular compartments. To examine whether the metabolic functions of these isozymes are interchangeable, we have altered the cellular localization of mitochondrial malate dehydrogenase (MDH1) in yeast. Since a previous study showed that removal of the targeting presequence from MDH1 does not prevent mitochondrial import in vivo, we tested the role of a putative cryptic targeting sequence near the amine terminus of the mature polypeptide. Three residues in this region were changed to residues present in analogous positions in the other two yeast MDH isozymes. Alone, these replacements did not affect activity or localization of MDH1 but, in combination with deletion of the presequence, prevented mitochondrial import in vivo. Measurable levels of the resulting cytosolic form of MDH1 were low with expression from a centromere-based plasmid but were comparable to normal cellular levels with expression from a multicopy plasmid. The cytosolic form of MDH1 restored the ability of a ΔMDH1 disruption strain to grow on ethanol or acetate, suggesting that mitochondrial localization of MDH1 is not essential for its function in the TCA cycle. This TCA cycle function observed for the cytosolic form of MDH1 is unique to that isozyme since overexpression of MDH2 and of a cytosolic form of MDH3 in a ΔMDH1 strain failed to restore growth. Finally, only partial restoration of growth of a ΔMDH2 disruption mutant was attained with the cytosolic form of MDH1, suggesting that MDH2 may also have unique metabolic functions.

Original languageEnglish (US)
Pages (from-to)53-60
Number of pages8
JournalArchives of Biochemistry and Biophysics
Volume344
Issue number1
DOIs
StatePublished - Aug 1 1997

Fingerprint

Malate Dehydrogenase
Yeast
Isoenzymes
Yeasts
Plasmids
Centromere
Eukaryotic Cells
Growth
Restoration
Amines
Acetates
Ethanol
Peptides

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

Metabolic effects of altering redundant targeting signals for yeast mitochondrial malate dehydrogenase. / Small, W. C.; McAlister-Henn, L.

In: Archives of Biochemistry and Biophysics, Vol. 344, No. 1, 01.08.1997, p. 53-60.

Research output: Contribution to journalArticle

@article{ed95aeb85e6d405abcdda21d865ced8d,
title = "Metabolic effects of altering redundant targeting signals for yeast mitochondrial malate dehydrogenase",
abstract = "Eukaryotic cells contain highly homologous isozymes of malate dehydrogenase which catalyze the same reaction in different cellular compartments. To examine whether the metabolic functions of these isozymes are interchangeable, we have altered the cellular localization of mitochondrial malate dehydrogenase (MDH1) in yeast. Since a previous study showed that removal of the targeting presequence from MDH1 does not prevent mitochondrial import in vivo, we tested the role of a putative cryptic targeting sequence near the amine terminus of the mature polypeptide. Three residues in this region were changed to residues present in analogous positions in the other two yeast MDH isozymes. Alone, these replacements did not affect activity or localization of MDH1 but, in combination with deletion of the presequence, prevented mitochondrial import in vivo. Measurable levels of the resulting cytosolic form of MDH1 were low with expression from a centromere-based plasmid but were comparable to normal cellular levels with expression from a multicopy plasmid. The cytosolic form of MDH1 restored the ability of a ΔMDH1 disruption strain to grow on ethanol or acetate, suggesting that mitochondrial localization of MDH1 is not essential for its function in the TCA cycle. This TCA cycle function observed for the cytosolic form of MDH1 is unique to that isozyme since overexpression of MDH2 and of a cytosolic form of MDH3 in a ΔMDH1 strain failed to restore growth. Finally, only partial restoration of growth of a ΔMDH2 disruption mutant was attained with the cytosolic form of MDH1, suggesting that MDH2 may also have unique metabolic functions.",
author = "Small, {W. C.} and L. McAlister-Henn",
year = "1997",
month = "8",
day = "1",
doi = "10.1006/abbi.1997.0179",
language = "English (US)",
volume = "344",
pages = "53--60",
journal = "Archives of Biochemistry and Biophysics",
issn = "0003-9861",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - Metabolic effects of altering redundant targeting signals for yeast mitochondrial malate dehydrogenase

AU - Small, W. C.

AU - McAlister-Henn, L.

PY - 1997/8/1

Y1 - 1997/8/1

N2 - Eukaryotic cells contain highly homologous isozymes of malate dehydrogenase which catalyze the same reaction in different cellular compartments. To examine whether the metabolic functions of these isozymes are interchangeable, we have altered the cellular localization of mitochondrial malate dehydrogenase (MDH1) in yeast. Since a previous study showed that removal of the targeting presequence from MDH1 does not prevent mitochondrial import in vivo, we tested the role of a putative cryptic targeting sequence near the amine terminus of the mature polypeptide. Three residues in this region were changed to residues present in analogous positions in the other two yeast MDH isozymes. Alone, these replacements did not affect activity or localization of MDH1 but, in combination with deletion of the presequence, prevented mitochondrial import in vivo. Measurable levels of the resulting cytosolic form of MDH1 were low with expression from a centromere-based plasmid but were comparable to normal cellular levels with expression from a multicopy plasmid. The cytosolic form of MDH1 restored the ability of a ΔMDH1 disruption strain to grow on ethanol or acetate, suggesting that mitochondrial localization of MDH1 is not essential for its function in the TCA cycle. This TCA cycle function observed for the cytosolic form of MDH1 is unique to that isozyme since overexpression of MDH2 and of a cytosolic form of MDH3 in a ΔMDH1 strain failed to restore growth. Finally, only partial restoration of growth of a ΔMDH2 disruption mutant was attained with the cytosolic form of MDH1, suggesting that MDH2 may also have unique metabolic functions.

AB - Eukaryotic cells contain highly homologous isozymes of malate dehydrogenase which catalyze the same reaction in different cellular compartments. To examine whether the metabolic functions of these isozymes are interchangeable, we have altered the cellular localization of mitochondrial malate dehydrogenase (MDH1) in yeast. Since a previous study showed that removal of the targeting presequence from MDH1 does not prevent mitochondrial import in vivo, we tested the role of a putative cryptic targeting sequence near the amine terminus of the mature polypeptide. Three residues in this region were changed to residues present in analogous positions in the other two yeast MDH isozymes. Alone, these replacements did not affect activity or localization of MDH1 but, in combination with deletion of the presequence, prevented mitochondrial import in vivo. Measurable levels of the resulting cytosolic form of MDH1 were low with expression from a centromere-based plasmid but were comparable to normal cellular levels with expression from a multicopy plasmid. The cytosolic form of MDH1 restored the ability of a ΔMDH1 disruption strain to grow on ethanol or acetate, suggesting that mitochondrial localization of MDH1 is not essential for its function in the TCA cycle. This TCA cycle function observed for the cytosolic form of MDH1 is unique to that isozyme since overexpression of MDH2 and of a cytosolic form of MDH3 in a ΔMDH1 strain failed to restore growth. Finally, only partial restoration of growth of a ΔMDH2 disruption mutant was attained with the cytosolic form of MDH1, suggesting that MDH2 may also have unique metabolic functions.

UR - http://www.scopus.com/inward/record.url?scp=0031214131&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031214131&partnerID=8YFLogxK

U2 - 10.1006/abbi.1997.0179

DO - 10.1006/abbi.1997.0179

M3 - Article

C2 - 9244381

AN - SCOPUS:0031214131

VL - 344

SP - 53

EP - 60

JO - Archives of Biochemistry and Biophysics

JF - Archives of Biochemistry and Biophysics

SN - 0003-9861

IS - 1

ER -