Pathway Human Homo sapiens

Mitochondrial translation

R-HSA-5368287 in Reactome release 97: under Translation, with 114 genes placed in it by the mapping files and 4 child pathways in the hierarchy.

The same number in the other species

Reactome writes the mouse and rat events it infers from a human pathway under the human number with the species token. A door opens only where that species' own list in this release holds the id: R-MMU-5368287 (mouse), R-RNO-5368287 (rat). Whether the event was inferred from this one is what the record says.

The record
The genes
Parents and children

Scripts are off

This page reads the pathway's record from its source while you read the rest; with scripts off the card stays at its loading line. Reload with scripts on to see it, or open the source's own page from the link in the card.

01The record

Reactome's own record of this pathway

What this tells you

The pathway list, the hierarchy and the genes on this page are read from the files Reactome publishes for Reactome release 97, built into this site on 2026-09-09: the pathway list, the hierarchy relationship file and the two gene mapping files. The record card is the one live read, Reactome's own record of this pathway.

Reactome's download page describes the mapping files: Mapping files link the source database identifier to the lowest level pathway diagram or subset of the pathway, all levels of the pathway hierarchy or database identifier to all reactions. [R13] The gene list here is the all-levels mapping of NCBI Gene ids, filled from the all-levels mapping of Ensembl ids where the NCBI file has no row for a gene; each row names which file it came from by the shape of its source id. Each row carries the evidence codes the file writes for it, as written and unranked, and both where the file writes both; no page of Reactome's documentation the survey read defines the codes, so this page does not expand them. A gene id the identity files do not name is kept as the source's own id with no door rather than turned into a symbol.

On citing what a search finds, Reactome says: It should be remembered that while we strive to contain the most current and accurate data, Reactome should not be used in citations where other primary sources of information are available. [R12] The record card prints the literature Reactome attaches to a curated pathway for that reason. The data are public domain: All data in the Reactome database and files derived from that data are licensed under the Creative Commons Public Domain Dedication (CC0). User may copy, modify, and distribute these data, even for commercial purposes, without asking for permission. Attribution is encouraged but not required. [R10] The pathway illustrations are licensed apart, under CC BY 4.0, and none is shown here.

A gene on this list is one Reactome places in this pathway in this release, and that is all the row says: it does not say the gene is expressed in a tissue or associated with a disease, which are the other two explorers' questions, read from other sources. Reactome's papers of record are [R01] [R02].

[R01] Ragueneau E, Gong C, Sinquin P, Sevilla C, Beavers D, Grentner A, et al. (2026). The Reactome Knowledgebase 2026. Nucleic Acids Research 54:D673-D681. PMID 41251150, doi 10.1093/nar/gkaf1223.
[R02] Milacic M, Beavers D, Conley P, Gong C, Gillespie M, Griss J, et al. (2024). The Reactome Pathway Knowledgebase 2024. Nucleic Acids Research 52:D672-D678. PMID 37941124, doi 10.1093/nar/gkad1025.
[R10] Reactome, reactome.org. License Agreement. https://reactome.org/license, read 2026-09-09.
[R12] Reactome, reactome.org. Citing us. https://reactome.org/cite, read 2026-09-09.
[R13] Reactome, reactome.org. Download. https://reactome.org/download-data, read 2026-09-09.

Stable id: R-HSA-5368287.6
Class: Pathway
Species: Homo sapiens (human)
Inferred: no: a curated human pathway
Disease pathway: no
Released: 2014-09-30
Last updated: 2016-03-24
Events inside: 4, counted from the record

Of the roughly 1000 human mitochondrial proteins only 13 proteins, all of them hydrophobic inner membrane proteins that are components of the oxidative phosphorylation apparatus, are encoded in the mitochondrial genome and translated by mitoribosomes at the matrix face of the inner membrane (reviewed in Herrmann et al. 2012, Hallberg and Larsson 2014, Lightowlers et al. 2014). The remainder, including all proteins of the mitochondrial translation system, are encoded in the nucleus and imported from the cytosol into the mitochondrion. Translation in the mitochondrion reflects both the bacterial origin of the organelle and subsequent divergent evolution during symbiosis (reviewed in Huot et al. 2014, Richman et al. 2014). Human mitochondrial ribosomes have a low sedimentation coefficient of only 55S, but at 2.71 MDa they retain a similar mass to E. coli 70S particles. The 55S particles are protein-rich compared to both cytosolic ribosomes and eubacterial ribosomes. This is due to shorter mt-rRNAs, mitochondria-specific proteins, and numerous rearrangements in individual protein positions within the two ribosome subunits (inferred from bovine ribosomes in Sharma et al. 2003, Greber et al. 2014, Kaushal et al. 2014, reviewed in Agrawal and Sharma 2012).

Mitochondrial mRNAs have either no untranslated leader or short leaders of 1-3 nucleotides, with the exception of the 2 bicistronic transcripts, RNA7 and RNA14, which have overlapping orfs that encode ND4L/ND4 and ATP8/ATP6 respectively. Translation is believed to initiate with the mRNA binding the 28S subunit:MTIF3 (28S subunit:IF-3Mt, 28S subunit:IF2mt) complex together with MTIF2:GTP (IF-2Mt:GTP, IF2mt:GTP) at the matrix face of the inner membrane (reviewed in Christian and Spremulli 2012). MTIF3 can dissociate 55S particles in preparation for initiation, enhances formation of initiation complexes, and inhibits N-formylmethionine-tRNA (fMet-tRNA) binding to 28S subunits in the absence of mRNA. Binding of fMet-tRNA to the start codon of the mRNA results in a stable complex while absence of a start codon at the 5' end of the mRNA causes eventual dissociation of the mRNA from the 28S subunit. After recognition of a start codon, the 39S subunit then binds the stable complex, GTP is hydrolyzed, and the initiation factors MTIF3 and MTIF2:GDP dissociate.

Translation elongation then proceeds by cycles of aminoacyl-tRNAs binding, peptide bond formation, and displacement of deacylated tRNAs. In each cycle an aminoacyl-tRNA in a complex with TUFM:GTP (EF-Tu:GTP) binds at the A-site of the ribosome, GTP is hydrolyzed, and TUFM:GDP dissociates. The elongating polypeptide bonded to the tRNA at the P-site is transferred to the aminoacyl group at the A-site by peptide bond formation at the peptidyl transferase center, leaving a deacylated tRNA at the P-site and the elongating polypeptide attached to the tRNA at the A-site. The polypeptide is co-translationally inserted into the inner mitochondrial membrane via an interaction with OXA1L (Haque et al. 2010, reviewed in Ott and Hermann 2010). After peptide bond formation, GFM1:GTP (EF-Gmt:GTP) then binds the ribosome complex, GTP is hydrolyzed, GFM1:GDP dissociates, and the ribosome translocates 3 nucleotides in the 3' direction along the mRNA, relocating the polypeptide-tRNA to the P-site and allowing another cycle to begin. TUFM:GDP is regenerated to TUFM:GTP by the guanine nucleotide exchange factor TSFM (EF-Ts, EF-TsMt).

Translation is terminated when MTRF1L:GTP (MTRF1a:GTP) recognizes an UAA or UAG termination codon at the A-site of the ribosome (Tsuboi et al. 2009). GTP hydrolysis does not appear to be required. The tRNA-aminoacyl bond between the translated polypeptide and the final tRNA at the P-site is hydrolyzed by the 39S subunit, facilitating release of the polypeptide. MRRF (RRF) and GFM2:GTP (EF-G2mt:GTP) then act to release the remaining tRNA and mRNA from the ribosome and dissociate the 55S ribosome into 28S and 39S subunits.

Mutations have been identified in genes encoding mitochondrial ribosomal proteins and translation factors. These have been shown to be pathogenic, causing neurological and other diseases (reviewed in Koopman et al. 2013, Pearce et al. 2013).

Translation can stall due to lack of tRNAs or due to defects in mRNAs and tRNAs (reviewed in Yip and Shao 2021, Nadler et al. 2022). In the case of a defective tRNA, the 28S and 39S ribosomal subunits are separated and the MTRFR-MTRES1 complex binds the peptidyl-tRNA and the empty A-site of the ribosome, resulting in ejection and hydrolysis of the peptidyl-tRNA and regeneration of the tRNA and the 39S ribosomal subunit (Desai et al 2020). In the case of a mRNA lacking a stop codon (non-stop mRNA), ICT1 recognizes the empty mRNA channel in the ribosome and causes ejection and hydrolysis of the peptidyl-tRNA (Kummer et al. 2021, Richter et al. 2010, Feaga et al. 2016).

Literature Reactome attaches

Mechanism of protein biosynthesis in mammalian mitochondriaBiochim. Biophys. Acta, 2012, vol. 1819, p. 1035-54PubMed 22172991
Idiosyncrasies in decoding mitochondrial genomesBiochimie, 2014, vol. 100, p. 95-106PubMed 24440477
Supernumerary proteins of mitochondrial ribosomesBiochim. Biophys. Acta, 2014, vol. 1840, p. 1227-32PubMed 23958563
Biogenesis of mitochondrial proteinsAdv. Exp. Med. Biol., 2012, vol. 748, p. 41-64PubMed 22729854
Mitochondrial diseases: translation mattersMol. Cell. Neurosci., 2013, vol. 55, p. 1-12PubMed 22986124
Structural aspects of mitochondrial translational apparatusCurr. Opin. Struct. Biol., 2012, vol. 22, p. 797-803PubMed 22959417
EF-G2mt is an exclusive recycling factor in mammalian mitochondrial protein synthesisMol. Cell, 2009, vol. 35, p. 502-10PubMed 19716793

Reactome's record lists 10 orthologous events, R-MMU-5368287 (Mus musculus), R-RNO-5368287 (Rattus norvegicus) among the species this site serves, and 8 in species this site opens no page for.

Reactome ContentService, this pathway's record · Reactome v97 · read 2026-09-30 ET · Reactome pathway browser"Mitochondrial translation". Reactome, release 97, https://reactome.org/PathwayBrowser/#/R-HSA-5368287 with StableID: R-HSA-5368287.6 (accessed 2026-09-30 ET). Reactome version 97 (CC0).

Reading this pathway's record from Reactome (the pathway record).Still reading. A first read of a pathway can take a while; this page waits up to 35 seconds for it, and its scripts then bring in the panel, or a line saying what did not arrive.

02The genes

Genes Reactome places in this human pathway

The mapping files place 114 genes in this human pathway; showing 1 to 100, in pages of 100, sorted by symbol for reading. The order carries no ranking.

Genes Reactome places in this human pathway, page 1 of 2
Gene	Authority id	Mapping file id	Evidence codes
GeneAURKAIP1	AuthorityHGNC:24114	Mapping file id54998 NCBI file	EvidenceIEA, TAS
GeneCHCHD1	AuthorityHGNC:23518	Mapping file id118487 NCBI file	EvidenceIEA, TAS
GeneDAP3	AuthorityHGNC:2673	Mapping file id7818 NCBI file	EvidenceIEA, TAS
GeneERAL1	AuthorityHGNC:3424	Mapping file id26284 NCBI file	EvidenceIEA, TAS
GeneGADD45GIP1	AuthorityHGNC:29996	Mapping file id90480 NCBI file	EvidenceIEA, TAS
GeneGFM1	AuthorityHGNC:13780	Mapping file id85476 NCBI file	EvidenceIEA, TAS
GeneGFM2	AuthorityHGNC:29682	Mapping file id84340 NCBI file	EvidenceTAS
GeneKGD4	AuthorityHGNC:16631	Mapping file id92259 NCBI file	EvidenceIEA, TAS
GeneMALSU1	AuthorityHGNC:21721	Mapping file id115416 NCBI file	EvidenceTAS
GeneMIEF1	AuthorityHGNC:25979	Mapping file id54471 NCBI file	EvidenceTAS
GeneMRPL1	AuthorityHGNC:14275	Mapping file id65008 NCBI file	EvidenceIEA, TAS
GeneMRPL10	AuthorityHGNC:14055	Mapping file id124995 NCBI file	EvidenceIEA, TAS
GeneMRPL11	AuthorityHGNC:14042	Mapping file id65003 NCBI file	EvidenceIEA, TAS
GeneMRPL12	AuthorityHGNC:10378	Mapping file id6182 NCBI file	EvidenceIEA, TAS
GeneMRPL13	AuthorityHGNC:14278	Mapping file id28998 NCBI file	EvidenceIEA, TAS
GeneMRPL14	AuthorityHGNC:14279	Mapping file id64928 NCBI file	EvidenceIEA, TAS
GeneMRPL15	AuthorityHGNC:14054	Mapping file id29088 NCBI file	EvidenceIEA, TAS
GeneMRPL16	AuthorityHGNC:14476	Mapping file id54948 NCBI file	EvidenceIEA, TAS
GeneMRPL17	AuthorityHGNC:14053	Mapping file id63875 NCBI file	EvidenceIEA, TAS
GeneMRPL18	AuthorityHGNC:14477	Mapping file id29074 NCBI file	EvidenceIEA, TAS
GeneMRPL19	AuthorityHGNC:14052	Mapping file id9801 NCBI file	EvidenceIEA, TAS
GeneMRPL2	AuthorityHGNC:14056	Mapping file id51069 NCBI file	EvidenceIEA, TAS
GeneMRPL20	AuthorityHGNC:14478	Mapping file id55052 NCBI file	EvidenceIEA, TAS
GeneMRPL21	AuthorityHGNC:14479	Mapping file id219927 NCBI file	EvidenceIEA, TAS
GeneMRPL22	AuthorityHGNC:14480	Mapping file id29093 NCBI file	EvidenceIEA, TAS
GeneMRPL23	AuthorityHGNC:10322	Mapping file id6150 NCBI file	EvidenceIEA, TAS
GeneMRPL24	AuthorityHGNC:14037	Mapping file id79590 NCBI file	EvidenceIEA, TAS
GeneMRPL27	AuthorityHGNC:14483	Mapping file id51264 NCBI file	EvidenceIEA, TAS
GeneMRPL28	AuthorityHGNC:14484	Mapping file id10573 NCBI file	EvidenceIEA, TAS
GeneMRPL3	AuthorityHGNC:10379	Mapping file id11222 NCBI file	EvidenceIEA, TAS
GeneMRPL30	AuthorityHGNC:14036	Mapping file id51263 NCBI file	EvidenceIEA, TAS
GeneMRPL32	AuthorityHGNC:14035	Mapping file id64983 NCBI file	EvidenceIEA, TAS
GeneMRPL33	AuthorityHGNC:14487	Mapping file id9553 NCBI file	EvidenceIEA, TAS
GeneMRPL34	AuthorityHGNC:14488	Mapping file id64981 NCBI file	EvidenceIEA, TAS
GeneMRPL35	AuthorityHGNC:14489	Mapping file id51318 NCBI file	EvidenceIEA, TAS
GeneMRPL36	AuthorityHGNC:14490	Mapping file id64979 NCBI file	EvidenceIEA, TAS
GeneMRPL37	AuthorityHGNC:14034	Mapping file id51253 NCBI file	EvidenceIEA, TAS
GeneMRPL38	AuthorityHGNC:14033	Mapping file id64978 NCBI file	EvidenceIEA, TAS
GeneMRPL39	AuthorityHGNC:14027	Mapping file id54148 NCBI file	EvidenceIEA, TAS
GeneMRPL4	AuthorityHGNC:14276	Mapping file id51073 NCBI file	EvidenceIEA, TAS
GeneMRPL40	AuthorityHGNC:14491	Mapping file id64976 NCBI file	EvidenceIEA, TAS
GeneMRPL41	AuthorityHGNC:14492	Mapping file id64975 NCBI file	EvidenceIEA, TAS
GeneMRPL42	AuthorityHGNC:14493	Mapping file id28977 NCBI file	EvidenceIEA, TAS
GeneMRPL43	AuthorityHGNC:14517	Mapping file id84545 NCBI file	EvidenceIEA, TAS
GeneMRPL44	AuthorityHGNC:16650	Mapping file id65080 NCBI file	EvidenceIEA, TAS
GeneMRPL46	AuthorityHGNC:1192	Mapping file id26589 NCBI file	EvidenceIEA, TAS
GeneMRPL47	AuthorityHGNC:16652	Mapping file id57129 NCBI file	EvidenceIEA, TAS
GeneMRPL48	AuthorityHGNC:16653	Mapping file id51642 NCBI file	EvidenceIEA, TAS
GeneMRPL49	AuthorityHGNC:1176	Mapping file id740 NCBI file	EvidenceIEA, TAS
GeneMRPL50	AuthorityHGNC:16654	Mapping file id54534 NCBI file	EvidenceIEA, TAS
GeneMRPL51	AuthorityHGNC:14044	Mapping file id51258 NCBI file	EvidenceIEA, TAS
GeneMRPL52	AuthorityHGNC:16655	Mapping file id122704 NCBI file	EvidenceIEA, TAS
GeneMRPL53	AuthorityHGNC:16684	Mapping file id116540 NCBI file	EvidenceIEA, TAS
GeneMRPL54	AuthorityHGNC:16685	Mapping file id116541 NCBI file	EvidenceIEA, TAS
GeneMRPL55	AuthorityHGNC:16686	Mapping file id128308 NCBI file	EvidenceIEA, TAS
GeneMRPL57	AuthorityHGNC:14514	Mapping file id78988 NCBI file	EvidenceIEA, TAS
GeneMRPL58	AuthorityHGNC:5359	Mapping file id3396 NCBI file	EvidenceIEA, TAS
GeneMRPL9	AuthorityHGNC:14277	Mapping file id65005 NCBI file	EvidenceIEA, TAS
GeneMRPS10	AuthorityHGNC:14502	Mapping file id55173 NCBI file	EvidenceIEA, TAS
GeneMRPS11	AuthorityHGNC:14050	Mapping file id64963 NCBI file	EvidenceIEA, TAS
GeneMRPS12	AuthorityHGNC:10380	Mapping file id6183 NCBI file	EvidenceIEA, TAS
GeneMRPS14	AuthorityHGNC:14049	Mapping file id63931 NCBI file	EvidenceIEA, TAS
GeneMRPS15	AuthorityHGNC:14504	Mapping file id64960 NCBI file	EvidenceIEA, TAS
GeneMRPS16	AuthorityHGNC:14048	Mapping file id51021 NCBI file	EvidenceIEA, TAS
GeneMRPS17	AuthorityHGNC:14047	Mapping file id51373 NCBI file	EvidenceIEA, TAS
GeneMRPS18A	AuthorityHGNC:14515	Mapping file id55168 NCBI file	EvidenceIEA, TAS
GeneMRPS18B	AuthorityHGNC:14516	Mapping file id28973 NCBI file	EvidenceIEA, TAS
GeneMRPS18C	AuthorityHGNC:16633	Mapping file id51023 NCBI file	EvidenceIEA, TAS
GeneMRPS2	AuthorityHGNC:14495	Mapping file id51116 NCBI file	EvidenceIEA, TAS
GeneMRPS21	AuthorityHGNC:14046	Mapping file id54460 NCBI file	EvidenceIEA, TAS
GeneMRPS22	AuthorityHGNC:14508	Mapping file id56945 NCBI file	EvidenceIEA, TAS
GeneMRPS23	AuthorityHGNC:14509	Mapping file id51649 NCBI file	EvidenceIEA, TAS
GeneMRPS24	AuthorityHGNC:14510	Mapping file id64951 NCBI file	EvidenceIEA, TAS
GeneMRPS25	AuthorityHGNC:14511	Mapping file id64432 NCBI file	EvidenceIEA, TAS
GeneMRPS26	AuthorityHGNC:14045	Mapping file id64949 NCBI file	EvidenceIEA, TAS
GeneMRPS27	AuthorityHGNC:14512	Mapping file id23107 NCBI file	EvidenceIEA, TAS
GeneMRPS28	AuthorityHGNC:14513	Mapping file id28957 NCBI file	EvidenceIEA, TAS
GeneMRPS30	AuthorityHGNC:8769	Mapping file id10884 NCBI file	EvidenceIEA, TAS
GeneMRPS31	AuthorityHGNC:16632	Mapping file id10240 NCBI file	EvidenceIEA, TAS
GeneMRPS33	AuthorityHGNC:16634	Mapping file id51650 NCBI file	EvidenceIEA, TAS
GeneMRPS34	AuthorityHGNC:16618	Mapping file id65993 NCBI file	EvidenceIEA, TAS
GeneMRPS35	AuthorityHGNC:16635	Mapping file id60488 NCBI file	EvidenceIEA, TAS
GeneMRPS5	AuthorityHGNC:14498	Mapping file id64969 NCBI file	EvidenceIEA, TAS
GeneMRPS6	AuthorityHGNC:14051	Mapping file id64968 NCBI file	EvidenceIEA, TAS
GeneMRPS7	AuthorityHGNC:14499	Mapping file id51081 NCBI file	EvidenceIEA, TAS
GeneMRPS9	AuthorityHGNC:14501	Mapping file id64965 NCBI file	EvidenceIEA, TAS
GeneMRRF	AuthorityHGNC:7234	Mapping file id92399 NCBI file	EvidenceTAS
GeneMT-ATP6	AuthorityHGNC:7414	Mapping file id4508 NCBI file	EvidenceTAS
GeneMT-ATP8	AuthorityHGNC:7415	Mapping file id4509 NCBI file	EvidenceTAS
GeneMT-CO1	AuthorityHGNC:7419	Mapping file id4512 NCBI file	EvidenceTAS
GeneMT-CO2	AuthorityHGNC:7421	Mapping file id4513 NCBI file	EvidenceTAS
GeneMT-CO3	AuthorityHGNC:7422	Mapping file id4514 NCBI file	EvidenceTAS
GeneMT-CYB	AuthorityHGNC:7427	Mapping file id4519 NCBI file	EvidenceTAS
GeneMT-ND1	AuthorityHGNC:7455	Mapping file id4535 NCBI file	EvidenceTAS
GeneMT-ND2	AuthorityHGNC:7456	Mapping file id4536 NCBI file	EvidenceTAS
GeneMT-ND3	AuthorityHGNC:7458	Mapping file id4537 NCBI file	EvidenceTAS
GeneMT-ND4	AuthorityHGNC:7459	Mapping file id4538 NCBI file	EvidenceTAS
GeneMT-ND4L	AuthorityHGNC:7460	Mapping file id4539 NCBI file	EvidenceTAS
GeneMT-ND5	AuthorityHGNC:7461	Mapping file id4540 NCBI file	EvidenceTAS
GeneMT-ND6	AuthorityHGNC:7462	Mapping file id4541 NCBI file	EvidenceTAS

Evidence codes on this page: IEA, TAS, as the mapping file writes them; a row carrying two was written twice by the file, once under each. The mapping file id says which file placed the gene: an NCBI Gene id from NCBI2Reactome_All_Levels.txt, an Ensembl gene id from Ensembl2Reactome_All_Levels.txt. The two files can disagree about a code, so a row's codes are the one file's view. Measured by this site's build over this release on 2026-09-09: of the 138,908 human pathway-gene pairs both files place, 207 (0.149 per cent, over 47 genes) carry TAS in the Ensembl file where the NCBI rows carry IEA alone.

Reactome mapping files, the human rows for this pathway · Reactome release 97 · read 2026-09-09 · Reactome downloads"NCBI2Reactome_All_Levels.txt" and "Ensembl2Reactome_All_Levels.txt", Reactome, release 97, https://reactome.org/download-data/ (date of access 2026-09-09). Data CC0; attribution encouraged.

03The hierarchy

Parents and children in this release's hierarchy

Parents

TranslationR-HSA-72766368 genes

Children

Reactome's hierarchy is a graph rather than a tree: a pathway can sit under more than one parent, and the gene counts are each pathway's own placements at every level under it, so a parent's count is not the sum of its children's.

Reactome, the human pathway list and hierarchy relationship file · Reactome release 97 · read 2026-09-09 · Reactome downloads"ReactomePathways.txt" and "ReactomePathwaysRelation.txt", Reactome, release 97, https://reactome.org/download-data/ (date of access 2026-09-09). Data CC0; attribution encouraged.