OXA1/YER154W Summary Help

Standard Name OXA1 1
Systematic Name YER154W
Feature Type ORF, Verified
Description Mitochondrial inner membrane insertase; mediates the insertion of both mitochondrial- and nuclear-encoded proteins from the matrix into the inner membrane; also has a role in insertion of carrier proteins into the inner membrane; acts as a voltage-gated ion channel, activated by substrate peptides; interacts with mitochondrial ribosomes; conserved from bacteria to animals (2, 3, 4, 5, 6 and see Summary Paragraph)
Also known as: PET1402
Name Description cytochrome OXidase Activity 1
Chromosomal Location
ChrV:475020 to 476228 | ORF Map | GBrowse
Genetic position: 112 cM
Gene Ontology Annotations All OXA1 GO evidence and references
  View Computational GO annotations for OXA1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 8 genes
Classical genetics
reduction of function
Large-scale survey
63 total interaction(s) for 49 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 5
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 19
  • Biochemical Activity: 1
  • Protein-RNA: 2
  • Reconstituted Complex: 3

Genetic Interactions
  • Dosage Rescue: 9
  • Phenotypic Enhancement: 2
  • Phenotypic Suppression: 2
  • Synthetic Growth Defect: 10
  • Synthetic Lethality: 1
  • Synthetic Rescue: 7

Expression Summary
Length (a.a.) 402
Molecular Weight (Da) 44,815
Isoelectric Point (pI) 10.94
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrV:475020 to 476228 | ORF Map | GBrowse
Genetic position: 112 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1209 475020..476228 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | TCDB | UniProtKB
Primary SGDIDS000000956

Oxa1p is a nuclearly-encoded insertase of the mitochondrial inner membrane that facilitates the insertion of both mitochondrially- and nuclearly-encoded proteins from the matrix into the inner membrane (7, 8, 4). A highly conserved member of the Oxa1/YidC/Alb3 protein family involved in the membrane insertion of proteins, Oxa1p has homologs in both prokaryotes and eukaryotes (9, 10, 3).

The matrix-exposed C-terminus of Oxa1p forms an alpha-helical domain that has the ability to bind to mitochondrial ribosomes. Ribosome binding and the physical interaction of translation complexes with the membrane-bound Oxa1p insertase facilitates the co-translational membrane insertion of mitochondrial translation products (4). Oxa1p is essential for the correct assembly of the cytochrome c oxidase, ATP synthase, and ubiquinol-cytochrome c oxidoreductase complexes of the mitochondrial respiratory chain (11, 12, 13). Specifically, Oxa1p is required to process the Cox2p subunit of the cytochrome c oxidase complex, and export its N- and C-termini to the intermembrane space (14, 9, 15). In the absence of a functional Oxa1p, Cox2p accumulates as its precursor form, pCoxII, and its translocation to the intermembrane space is prevented (16, 17). Oxa1p has a separable function in assembly of Atp9p, the mitochondrially-encoded subunit 9, into the F1F0-ATPase complex. In doing so, Oxa1p binds stably to fully-translated Atp9p and to other ATPase subunits (18). This is in contrast to the transient, cotranslational binding to mitochondrially-encoded subunits of cytochrome c oxidase exhibited by Oxa1p in its function as a membrane insertase for those subunits.

Oxa1p is essential for respiratory growth, and null mutations lead to complete respiratory deficiency and lack of cytochrome oxidase activity (2, 13). The oxa1 null mutant has an altered mitochondrial phospholipid composition, probably due to effects on transcription and membrane insertion of phosphatidylserine decarboxylase (Psd1p), which is a mitochondrial inner membrane enzyme largely responsible for the synthesis of mitochondrial phosphatidylethanolamine (19).

Last updated: 2008-04-29 Contact SGD

References cited on this page View Complete Literature Guide for OXA1
1) Bonnefoy N, et al.  (1994) OXA1, a Saccharomyces cerevisiae nuclear gene whose sequence is conserved from prokaryotes to eukaryotes controls cytochrome oxidase biogenesis. J Mol Biol 239(2):201-12
2) Bonnefoy N, et al.  (1994) Cloning of a human gene involved in cytochrome oxidase assembly by functional complementation of an oxa1- mutation in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 91(25):11978-82
3) Jia L, et al.  (2003) Yeast Oxa1 interacts with mitochondrial ribosomes: the importance of the C-terminal region of Oxa1. EMBO J 22(24):6438-47
4) Szyrach G, et al.  (2003) Ribosome binding to the Oxa1 complex facilitates co-translational protein insertion in mitochondria. EMBO J 22(24):6448-57
5) Krueger V, et al.  (2012) The mitochondrial oxidase assembly protein1 (Oxa1) insertase forms a membrane pore in lipid bilayers. J Biol Chem 287(40):33314-26
6) Hildenbeutel M, et al.  (2012) The membrane insertase Oxa1 is required for efficient import of carrier proteins into mitochondria. J Mol Biol 423(4):590-9
7) Herrmann JM, et al.  (1997) Insertion into the mitochondrial inner membrane of a polytopic protein, the nuclear-encoded Oxa1p. EMBO J 16(9):2217-26
8) Herrmann JM and Bonnefoy N  (2004) Protein export across the inner membrane of mitochondria: the nature of translocated domains determines the dependence on the Oxa1 translocase. J Biol Chem 279(4):2507-12
9) Hell K, et al.  (1998) Oxa1p, an essential component of the N-tail protein export machinery in mitochondria. Proc Natl Acad Sci U S A 95(5):2250-5
10) Hamel P, et al.  (1998) Mutations in the membrane anchor of yeast cytochrome c1 compensate for the absence of Oxa1p and generate carbonate-extractable forms of cytochrome c1. Genetics 150(2):601-11
11) Altamura N, et al.  (1996) The Saccharomyces cerevisiae OXA1 gene is required for the correct assembly of cytochrome c oxidase and oligomycin-sensitive ATP synthase. FEBS Lett 382(1-2):111-5
12) Meyer W, et al.  (1997) Mitochondrial inner membrane bound Pet1402 protein is rapidly imported into mitochondria and affects the integrity of the cytochrome oxidase and ubiquinol-cytochrome c oxidoreductase complexes. Biol Chem 378(11):1373-9
13) Hamel P, et al.  (1997) Functional complementation of an oxa1- yeast mutation identifies an Arabidopsis thaliana cDNA involved in the assembly of respiratory complexes. Plant J 12(6):1319-27
14) He CH, et al.  (1996) Functional mitochondria are essential for Saccharomyces cerevisiae cellular resistance to bleomycin. Curr Genet 30(4):279-83
15) Fiumera HL, et al.  (2007) Translocation of mitochondrially synthesized Cox2 domains from the matrix to the intermembrane space. Mol Cell Biol 27(13):4664-73
16) Hell K, et al.  (1997) Oxa1p mediates the export of the N- and C-termini of pCoxII from the mitochondrial matrix to the intermembrane space. FEBS Lett 418(3):367-70
17) Lemaire C, et al.  (2000) Absence of the mitochondrial AAA protease Yme1p restores F0-ATPase subunit accumulation in an oxa1 deletion mutant of Saccharomyces cerevisiae. J Biol Chem 275(31):23471-5
18) Jia L, et al.  (2007) Oxa1 directly interacts with Atp9 and mediates its assembly into the mitochondrial F1Fo-ATP synthase complex. Mol Biol Cell 18(5):1897-908
19) Nebauer R, et al.  (2007) The phosphatidylethanolamine level of yeast mitochondria is affected by the mitochondrial components Oxa1p and Yme1p. FEBS J 274(23):6180-90