ETR1/YBR026C Summary Help

Standard Name ETR1
Systematic Name YBR026C
Alias MRF1 , MRF1'
Feature Type ORF, Verified
Description 2-enoyl thioester reductase; member of the medium chain dehydrogenase/reductase family; localized to in mitochondria, where it has a probable role in fatty acid synthesis (1 and see Summary Paragraph)
Name Description 2-Enoyl Thioester Reductase
Chromosomal Location
ChrII:294019 to 292877 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All ETR1 GO evidence and references
  View Computational GO annotations for ETR1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 9 genes
Classical genetics
Large-scale survey
186 total interaction(s) for 150 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 5
  • Affinity Capture-RNA: 1

Genetic Interactions
  • Dosage Growth Defect: 1
  • Dosage Lethality: 1
  • Negative Genetic: 125
  • Phenotypic Suppression: 2
  • Positive Genetic: 40
  • Synthetic Growth Defect: 10
  • Synthetic Rescue: 1

Expression Summary
Length (a.a.) 380
Molecular Weight (Da) 42,067
Isoelectric Point (pI) 9.78
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrII:294019 to 292877 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2004-07-16 | Sequence: 1997-01-28
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1143 294019..292877 2004-07-16 1997-01-28
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000000230

ETR1 encodes a member of the medium chain dehydrogenase/reductase family with 2-enoyl thioester reductase activity (E.C. number 1.3.1.-) (1). Etr1p is located in mitochondria, where it has a probable role in fatty acid synthesis (1). The etr1 null mutant is unable to grow on nonfermentable carbon sources and displays decreased mitochondrial cytochrome content. The null phenotypes are complemented by expression of the Etr1p ortholog from Candida tropicalis, or by targeting E. coli FabI, a NADPH-dependent 2-enoyl-acyl carrier protein reductase, to mitochondria (1). Although a previous study suggested that Etr1p (formerly known as Mrf1'p) is localized to the nucleus (2), a more recent study confirmed its mitochondrial localization and also showed that, when artificially targeted to the nucleus, Etr1p fails to complement the respiratory growth deficiency caused by the etr1 null mutation (1).

About the medium-chain dehydrogenase/reductase (MDR) family

Medium-chain dehydrogenase/reductases (MDRs), sometimes referred to as long-chain dehydrogenases (3), constitute an ancient and widespread enzyme superfamily with members found in Bacteria, Archaea, and Eukaryota (4, 5). Many MDR members are basic metabolic enzymes acting on alcohols or aldehydes, and thus these enzymes may have roles in detoxifying alcohols and related compounds, protecting against environmental stresses such as osmotic shock, reduced or elevated temperatures, or oxidative stress (4). The family also includes the mammalian zeta-crystallin lens protein, which may protect the lens against oxidative damage and enzymes which produce lignocellulose in plants (4).

MDR enzymes typically have subunits of about 350 aa residues and are two-domain proteins, with a catalytic domain and a second domain for binding to the nicotinamide cofactor, either NAD(H) or NADP(H) (4, 5). They contain 0, 1, or 2 zinc atoms (6). When zinc is present, it is involved in catalysis at the active site.

Based on phylogenetic and sequence analysis, the members of the MDR superfamily can be further divided into more closely related subgroups (4, 5). In families which are widespread from prokaryotes to eukaryotes, some members appear conserved across all species, while others appear to be due to lineage specific duplications. Some subgroups are only found in certain taxa. S. cerevisiae contains fifteen (4) or twenty-one (5) members of the MDR superfamily, listed below. The difference in number is due to six sequences that were included as members of the quinone oxidoreductase family by Riveros-Rosas et al. (5) but not by Nordling et al. (4).

Zinc-containing enzyme groups:
- PDH; "polyol" dehydrogenase family - BDH1, BDH2, SOR1, SOR2, XYL2
- ADH; class III alcohol dehydrogenase family - SFA1
- Y-ADH; "yeast" alcohol dehydrogenase family - ADH1, ADH2, ADH3, ADH5
- CADH; cinnamyl alcohol dehydrogenase family - ADH6, ADH7

Non-zinc-containing enzyme groups:
- NRBP; nuclear receptor binding protein (5) or MRF; mitochondrial respiratory function (4) family - ETR1
- QOR; quinone oxidoreductase family - ZTA1 (4, 5), AST1, AST2, YCR102C, YLR460C, YMR152W, YNL134C (5)
- LTD; leukotriene B4 dehydrogenases - YML131W
- ER; enoyl reductases (5) or ACR; acyl-CoA reductase (4) family - no members in S. cerevisiae

Last updated: 2002-12-04 Contact SGD

References cited on this page View Complete Literature Guide for ETR1
1) Torkko JM, et al.  (2001) Candida tropicalis Etr1p and Saccharomyces cerevisiae Ybr026p (Mrf1'p), 2-enoyl thioester reductases essential for mitochondrial respiratory competence. Mol Cell Biol 21(18):6243-53
2) Yamazoe M, et al.  (1994) A protein which binds preferentially to single-stranded core sequence of autonomously replicating sequence is essential for respiratory function in mitochondrial of Saccharomyces cerevisiae. J Biol Chem 269(21):15244-52
3) Jornvall H, et al.  (1981) Alcohol and polyol dehydrogenases are both divided into two protein types, and structural properties cross-relate the different enzyme activities within each type. Proc Natl Acad Sci U S A 78(7):4226-30
4) Nordling E, et al.  (2002) Medium-chain dehydrogenases/reductases (MDR). Family characterizations including genome comparisons and active site modeling. Eur J Biochem 269(17):4267-76
5) Riveros-Rosas H, et al.  (2003) Diversity, taxonomy and evolution of medium-chain dehydrogenase/reductase superfamily. Eur J Biochem 270(16):3309-34
6) Persson B, et al.  (1999) Bioinformatics in studies of SDR and MDR enzymes. Adv Exp Med Biol 463():373-7