Requirements for the mitochondrial import and localization of dihydroorotate dehydrogenase
(2000) In European Journal of Biochemistry 267(7). p.2079-2087- Abstract
In animals, dihydroorotate dehydrogenase (DHODH) is a mitochondrial protein that carries out the fourth step in de novo pyrimidine biosynthesis. Because this is the only enzyme of this pathway that is localized to mitochondria and because the enzyme is cytosolic in some bacteria and fungi, we carried out studies to understand the mode of targeting of animal DHODH and its submitochondrial localization. Analysis of fractionated rat liver mitochondria revealed that DHODH is an integral membrane protein exposed to the intermembrane space. In vitro-synthesized Drosophila, rat and human DHODH proteins were efficiently imported into the intermembrane space of isolated yeast mitochondria. Import did not alter the size of the in vitro... (More)
In animals, dihydroorotate dehydrogenase (DHODH) is a mitochondrial protein that carries out the fourth step in de novo pyrimidine biosynthesis. Because this is the only enzyme of this pathway that is localized to mitochondria and because the enzyme is cytosolic in some bacteria and fungi, we carried out studies to understand the mode of targeting of animal DHODH and its submitochondrial localization. Analysis of fractionated rat liver mitochondria revealed that DHODH is an integral membrane protein exposed to the intermembrane space. In vitro-synthesized Drosophila, rat and human DHODH proteins were efficiently imported into the intermembrane space of isolated yeast mitochondria. Import did not alter the size of the in vitro synthesized protein, nor was there a detectable size difference when compared to the DHODH protein found in vivo. Thus, there is no apparent proteolytic processing of the protein during import either in vitro or in vivo. Import of rat DHODH into isolated yeast mitochondria required inner membrane potential and was at least partially dependent upon matrix ATP, indicating that its localization uses the well described import machinery of the mitochondrial inner membrane. The DHODH proteins of animals differ from the cytosolic proteins found in some bacteria and fungi by the presence of an N-terminal segment that resembles mitochondrial-targeting presequences. Deletion of the cationic portion of this N-terminal sequence from the rat DHODH protein blocked its import into isolated yeast mitochondria, whereas deletion of the adjacent hydrophobic segment resulted in import of the protein into the matrix. Thus, the N-terminus of the DHODH protein contains a bipartite signal that governs import and correct insertion into the mitochondrial inner membrane.
(Less)
- author
- Rawls, J ; Knecht, W LU ; Diekert, K ; Lill, R and Löffler, Monika
- publishing date
- 2000-04
- type
- Contribution to journal
- publication status
- published
- keywords
- Amino Acid Sequence, Animals, Base Sequence, Biological Transport, DNA Primers, Humans, Hydrolysis, Membrane Proteins/chemistry, Mitochondria/enzymology, Molecular Sequence Data, Oxidoreductases/chemistry, Oxidoreductases Acting on CH-CH Group Donors, Saccharomyces cerevisiae/enzymology
- in
- European Journal of Biochemistry
- volume
- 267
- issue
- 7
- pages
- 2079 - 2087
- publisher
- Wiley-Blackwell
- external identifiers
-
- scopus:0034070355
- pmid:10727948
- ISSN
- 0014-2956
- DOI
- 10.1046/j.1432-1327.2000.01213.x
- language
- English
- LU publication?
- no
- id
- d161dc79-0f76-4069-895e-d68143f199fd
- date added to LUP
- 2020-07-22 14:32:23
- date last changed
- 2024-01-17 10:08:43
@article{d161dc79-0f76-4069-895e-d68143f199fd,
abstract = {{<p>In animals, dihydroorotate dehydrogenase (DHODH) is a mitochondrial protein that carries out the fourth step in de novo pyrimidine biosynthesis. Because this is the only enzyme of this pathway that is localized to mitochondria and because the enzyme is cytosolic in some bacteria and fungi, we carried out studies to understand the mode of targeting of animal DHODH and its submitochondrial localization. Analysis of fractionated rat liver mitochondria revealed that DHODH is an integral membrane protein exposed to the intermembrane space. In vitro-synthesized Drosophila, rat and human DHODH proteins were efficiently imported into the intermembrane space of isolated yeast mitochondria. Import did not alter the size of the in vitro synthesized protein, nor was there a detectable size difference when compared to the DHODH protein found in vivo. Thus, there is no apparent proteolytic processing of the protein during import either in vitro or in vivo. Import of rat DHODH into isolated yeast mitochondria required inner membrane potential and was at least partially dependent upon matrix ATP, indicating that its localization uses the well described import machinery of the mitochondrial inner membrane. The DHODH proteins of animals differ from the cytosolic proteins found in some bacteria and fungi by the presence of an N-terminal segment that resembles mitochondrial-targeting presequences. Deletion of the cationic portion of this N-terminal sequence from the rat DHODH protein blocked its import into isolated yeast mitochondria, whereas deletion of the adjacent hydrophobic segment resulted in import of the protein into the matrix. Thus, the N-terminus of the DHODH protein contains a bipartite signal that governs import and correct insertion into the mitochondrial inner membrane.</p>}},
author = {{Rawls, J and Knecht, W and Diekert, K and Lill, R and Löffler, Monika}},
issn = {{0014-2956}},
keywords = {{Amino Acid Sequence; Animals; Base Sequence; Biological Transport; DNA Primers; Humans; Hydrolysis; Membrane Proteins/chemistry; Mitochondria/enzymology; Molecular Sequence Data; Oxidoreductases/chemistry; Oxidoreductases Acting on CH-CH Group Donors; Saccharomyces cerevisiae/enzymology}},
language = {{eng}},
number = {{7}},
pages = {{2079--2087}},
publisher = {{Wiley-Blackwell}},
series = {{European Journal of Biochemistry}},
title = {{Requirements for the mitochondrial import and localization of dihydroorotate dehydrogenase}},
url = {{http://dx.doi.org/10.1046/j.1432-1327.2000.01213.x}},
doi = {{10.1046/j.1432-1327.2000.01213.x}},
volume = {{267}},
year = {{2000}},
}