A human mitochondrion contains about 1500 proteins, more than 99% of which are encoded in the nucleus, synthesized in the cytosol and imported into the mitochondrion. Proteins are targeted to four locations (outer membrane, intermembrane space, inner membrane, and matrix) and must be sorted accordingly (reviewed in Kutik et al. 2007, Milenkovic et al. 2007, Bolender et al. 2008, Endo and Yamano 2009). Newly synthesized proteins are transported from the cytosol across the outer membrane by the TOMM40:TOMM70 complex. Proteins that contain presequences first interact with the TOMM20 subunit of the complex while proteins that contain internal targeting elements first interact with the TOMM70 subunit. After initial interaction the protein is conducted across the outer membrane by TOMM40 subunits. In yeast some proteins such as Aco1, Atp1, Cit1, Idh1, and Atp2 have both presequences that interact with TOM20 and mature regions that interact with TOM70 (Yamamoto et al. 2009). After passage across the outer membrane, proteins may be targeted to the outer membrane via the SAMM50 complex, to the inner membrane via the TIMM22 or TIMM23 complexes (reviewed in van der Laan et al. 2010), to the matrix via the TIMM23 complex (reviewed in van der Laan et al. 2010), or proteins may fold and remain in the intermembrane space (reviewed in Stojanovski et al. 2008, Deponte and Hell 2009, Sideris and Tokatlidis 2010). Presequences on matrix and inner membrane proteins cause interaction with TIMM23 complexes; internal targeting sequences cause outer membrane proteins to interact with the SAMM50 complex and inner membrane proteins to interact with the TIMM22 complex. While in the intermembrane space hydrophobic proteins are chaperoned by the TIMM8:TIMM13 complex and/or the TIMM9:TIMM10:FXC1 complex.
van der Laan M, Hutu DP, Rehling P.; ''On the mechanism of preprotein import by the mitochondrial presequence translocase.''; PubMedEurope PMCScholia
Roesch K, Hynds PJ, Varga R, Tranebjaerg L, Koehler CM.; ''The calcium-binding aspartate/glutamate carriers, citrin and aralar1, are new substrates for the DDP1/TIMM8a-TIMM13 complex.''; PubMedEurope PMCScholia
Sakowska P, Jans DC, Mohanraj K, Riedel D, Jakobs S, Chacinska A.; ''The Oxidation Status of Mic19 Regulates MICOS Assembly.''; PubMedEurope PMCScholia
Banci L, Bertini I, Ciofi-Baffoni S, Janicka A, Martinelli M, Kozlowski H, Palumaa P.; ''A structural-dynamical characterization of human Cox17.''; PubMedEurope PMCScholia
Endo T, Yamano K.; ''Multiple pathways for mitochondrial protein traffic.''; PubMedEurope PMCScholia
Teixeira PF, Pinho CM, Branca RM, Lehtiö J, Levine RL, Glaser E.; ''In vitro oxidative inactivation of human presequence protease (hPreP).''; PubMedEurope PMCScholia
De Marcos Lousa C, Trézéguet V, Dianoux AC, Brandolin G, Lauquin GJ.; ''The human mitochondrial ADP/ATP carriers: kinetic properties and biogenesis of wild-type and mutant proteins in the yeast S. cerevisiae.''; PubMedEurope PMCScholia
Deponte M, Hell K.; ''Disulphide bond formation in the intermembrane space of mitochondria.''; PubMedEurope PMCScholia
Milenkovic D, Müller J, Stojanovski D, Pfanner N, Chacinska A.; ''Diverse mechanisms and machineries for import of mitochondrial proteins.''; PubMedEurope PMCScholia
Sideris DP, Tokatlidis K.; ''Oxidative protein folding in the mitochondrial intermembrane space.''; PubMedEurope PMCScholia
Humphries AD, Streimann IC, Stojanovski D, Johnston AJ, Yano M, Hoogenraad NJ, Ryan MT.; ''Dissection of the mitochondrial import and assembly pathway for human Tom40.''; PubMedEurope PMCScholia
Di Fonzo A, Ronchi D, Lodi T, Fassone E, Tigano M, Lamperti C, Corti S, Bordoni A, Fortunato F, Nizzardo M, Napoli L, Donadoni C, Salani S, Saladino F, Moggio M, Bresolin N, Ferrero I, Comi GP.; ''The mitochondrial disulfide relay system protein GFER is mutated in autosomal-recessive myopathy with cataract and combined respiratory-chain deficiency.''; PubMedEurope PMCScholia
Baertling F, A M van den Brand M, Hertecant JL, Al-Shamsi A, P van den Heuvel L, Distelmaier F, Mayatepek E, Smeitink JA, Nijtmans LG, Rodenburg RJ.; ''Mutations in COA6 cause cytochrome c oxidase deficiency and neonatal hypertrophic cardiomyopathy.''; PubMedEurope PMCScholia
Zhang Y, Deng H, Zhao Q, Li SJ.; ''Interaction of presequence peptides with human translocase of inner membrane of mitochondria Tim23.''; PubMedEurope PMCScholia
Fischer M, Horn S, Belkacemi A, Kojer K, Petrungaro C, Habich M, Ali M, Küttner V, Bien M, Kauff F, Dengjel J, Herrmann JM, Riemer J.; ''Protein import and oxidative folding in the mitochondrial intermembrane space of intact mammalian cells.''; PubMedEurope PMCScholia
Xie J, Marusich MF, Souda P, Whitelegge J, Capaldi RA.; ''The mitochondrial inner membrane protein mitofilin exists as a complex with SAM50, metaxins 1 and 2, coiled-coil-helix coiled-coil-helix domain-containing protein 3 and 6 and DnaJC11.''; PubMedEurope PMCScholia
Bauer MF, Gempel K, Reichert AS, Rappold GA, Lichtner P, Gerbitz KD, Neupert W, Brunner M, Hofmann S.; ''Genetic and structural characterization of the human mitochondrial inner membrane translocase.''; PubMedEurope PMCScholia
Yamano K, Kuroyanagi-Hasegawa M, Esaki M, Yokota M, Endo T.; ''Step-size analyses of the mitochondrial Hsp70 import motor reveal the Brownian ratchet in operation.''; PubMedEurope PMCScholia
Yamamoto H, Fukui K, Takahashi H, Kitamura S, Shiota T, Terao K, Uchida M, Esaki M, Nishikawa S, Yoshihisa T, Yamano K, Endo T.; ''Roles of Tom70 in import of presequence-containing mitochondrial proteins.''; PubMedEurope PMCScholia
Brunetti D, Torsvik J, Dallabona C, Teixeira P, Sztromwasser P, Fernandez-Vizarra E, Cerutti R, Reyes A, Preziuso C, D'Amati G, Baruffini E, Goffrini P, Viscomi C, Ferrero I, Boman H, Telstad W, Johansson S, Glaser E, Knappskog PM, Zeviani M, Bindoff LA.; ''Defective PITRM1 mitochondrial peptidase is associated with Aβ amyloidotic neurodegeneration.''; PubMedEurope PMCScholia
Bannwarth S, Ait-El-Mkadem S, Chaussenot A, Genin EC, Lacas-Gervais S, Fragaki K, Berg-Alonso L, Kageyama Y, Serre V, Moore DG, Verschueren A, Rouzier C, Le Ber I, Augé G, Cochaud C, Lespinasse F, N'Guyen K, de Septenville A, Brice A, Yu-Wai-Man P, Sesaki H, Pouget J, Paquis-Flucklinger V.; ''A mitochondrial origin for frontotemporal dementia and amyotrophic lateral sclerosis through CHCHD10 involvement.''; PubMedEurope PMCScholia
Farrell SR, Thorpe C.; ''Augmenter of liver regeneration: a flavin-dependent sulfhydryl oxidase with cytochrome c reductase activity.''; PubMedEurope PMCScholia
Dabir DV, Hasson SA, Setoguchi K, Johnson ME, Wongkongkathep P, Douglas CJ, Zimmerman J, Damoiseaux R, Teitell MA, Koehler CM.; ''A small molecule inhibitor of redox-regulated protein translocation into mitochondria.''; PubMedEurope PMCScholia
Kang Y, Fielden LF, Stojanovski D.; ''Mitochondrial protein transport in health and disease.''; PubMedEurope PMCScholia
Webb CT, Gorman MA, Lazarou M, Ryan MT, Gulbis JM.; ''Crystal structure of the mitochondrial chaperone TIM9.10 reveals a six-bladed alpha-propeller.''; PubMedEurope PMCScholia
Kutik S, Guiard B, Meyer HE, Wiedemann N, Pfanner N.; ''Cooperation of translocase complexes in mitochondrial protein import.''; PubMedEurope PMCScholia
Banci L, Bertini I, Ciofi-Baffoni S, Jaiswal D, Neri S, Peruzzini R, Winkelmann J.; ''Structural characterization of CHCHD5 and CHCHD7: two atypical human twin CX9C proteins.''; PubMedEurope PMCScholia
Kozjak-Pavlovic V, Ross K, Benlasfer N, Kimmig S, Karlas A, Rudel T.; ''Conserved roles of Sam50 and metaxins in VDAC biogenesis.''; PubMedEurope PMCScholia
Li K, Warner CK, Hodge JA, Minoshima S, Kudoh J, Fukuyama R, Maekawa M, Shimizu Y, Shimizu N, Wallace DC.; ''A human muscle adenine nucleotide translocator gene has four exons, is located on chromosome 4, and is differentially expressed.''; PubMedEurope PMCScholia
Mühlenbein N, Hofmann S, Rothbauer U, Bauer MF.; ''Organization and function of the small Tim complexes acting along the import pathway of metabolite carriers into mammalian mitochondria.''; PubMedEurope PMCScholia
Alikhani N, Guo L, Yan S, Du H, Pinho CM, Chen JX, Glaser E, Yan SS.; ''Decreased proteolytic activity of the mitochondrial amyloid-β degrading enzyme, PreP peptidasome, in Alzheimer's disease brain mitochondria.''; PubMedEurope PMCScholia
Wiedemann N, Pfanner N.; ''Mitochondrial Machineries for Protein Import and Assembly.''; PubMedEurope PMCScholia
Liu Y, Clegg HV, Leslie PL, Di J, Tollini LA, He Y, Kim TH, Jin A, Graves LM, Zheng J, Zhang Y.; ''CHCHD2 inhibits apoptosis by interacting with Bcl-x L to regulate Bax activation.''; PubMedEurope PMCScholia
Pacheu-Grau D, Bareth B, Dudek J, Juris L, Vögtle FN, Wissel M, Leary SC, Dennerlein S, Rehling P, Deckers M.; ''Cooperation between COA6 and SCO2 in COX2 maturation during cytochrome c oxidase assembly links two mitochondrial cardiomyopathies.''; PubMedEurope PMCScholia
Mick DU, Dennerlein S, Wiese H, Reinhold R, Pacheu-Grau D, Lorenzi I, Sasarman F, Weraarpachai W, Shoubridge EA, Warscheid B, Rehling P.; ''MITRAC links mitochondrial protein translocation to respiratory-chain assembly and translational regulation.''; PubMedEurope PMCScholia
Hofmann S, Rothbauer U, Mühlenbein N, Baiker K, Hell K, Bauer MF.; ''Functional and mutational characterization of human MIA40 acting during import into the mitochondrial intermembrane space.''; PubMedEurope PMCScholia
Falkevall A, Alikhani N, Bhushan S, Pavlov PF, Busch K, Johnson KA, Eneqvist T, Tjernberg L, Ankarcrona M, Glaser E.; ''Degradation of the amyloid beta-protein by the novel mitochondrial peptidasome, PreP.''; PubMedEurope PMCScholia
Stojanovski D, Müller JM, Milenkovic D, Guiard B, Pfanner N, Chacinska A.; ''The MIA system for protein import into the mitochondrial intermembrane space.''; PubMedEurope PMCScholia
Pinho CM, Björk BF, Alikhani N, Bäckman HG, Eneqvist T, Fratiglioni L, Glaser E, Graff C.; ''Genetic and biochemical studies of SNPs of the mitochondrial A beta-degrading protease, hPreP.''; PubMedEurope PMCScholia
Aras S, Bai M, Lee I, Springett R, Hüttemann M, Grossman LI.; ''MNRR1 (formerly CHCHD2) is a bi-organellar regulator of mitochondrial metabolism.''; PubMedEurope PMCScholia
Sinha D, Srivastava S, Krishna L, D'Silva P.; ''Unraveling the intricate organization of mammalian mitochondrial presequence translocases: existence of multiple translocases for maintenance of mitochondrial function.''; PubMedEurope PMCScholia
Sinha D, Joshi N, Chittoor B, Samji P, D'Silva P.; ''Role of Magmas in protein transport and human mitochondria biogenesis.''; PubMedEurope PMCScholia
Daithankar VN, Schaefer SA, Dong M, Bahnson BJ, Thorpe C.; ''Structure of the human sulfhydryl oxidase augmenter of liver regeneration and characterization of a human mutation causing an autosomal recessive myopathy .''; PubMedEurope PMCScholia
Bolender N, Sickmann A, Wagner R, Meisinger C, Pfanner N.; ''Multiple pathways for sorting mitochondrial precursor proteins.''; PubMedEurope PMCScholia
The SAM50 complex (SAMM50 complex) is inferred from homologous subunits in Saccharomyces cerevisiae. Xie et al. (2007) found human SAM50 in a complex with metaxin 1, metaxin 2, mitofilin, CHCHD3, CHCHD6, and DnaJC1 however Kozjak-Pavlovic et al. (2007) found SAM50 in a separate complex from the metaxins.
As inferred from the yeast TIM23 complex, the human TIMM23 complex resides in the inner membrane of the mitochondrion and transfers precursor proteins to the inner membrane. The presequences of proteins targeted to the inner membrane are transferred to the matrix where they are cleaved. Sequences in the mature regions of the proteins then interact with the TIMM23 complex to halt transfer across the inner membrane and the proteins are released laterally into the inner membrane. TIMM21 is required. In yeast experimentally verified substrates of the TIM23 complex targeted to the inner membrane include CYB2, DLD (LDHD in human), ATP9 (ATP5G1 in human), COQ2, TIM54 (TIMM54 in human), COX4, COX5A, and ATP2 (ATP5B in human). Many other inner membrane proteins are believed to be substrates of the TIMM23 complex.
As inferred from the yeast TIM23 complex, the human TIMM23 complex resides in the inner membrane of the mitochondrion and transfers precursor proteins to the inner membrane. The TIMM23 complex appears to adopt different configurations (and perhaps different subunit compositions) depending on whether the substrate is destined for the inner membrane or the matrix. Here we refer to the TIMM23 SORT complex as the configuration that delivers inner membrane proteins. The TIMM21 subunit is required for this activity. In yeast, the N-terminal presequences of precursors first interact with TIM50 and TIM23 (TIMM50 and TIMM23 in human). The TIM17 and TIM23 subunits (TIMM17 and TIMM23 in human) form a channel and are required to initiate translocation of precursors. In yeast experimentally verified substrates of the TIM23 SORT complex targeted to the inner membrane include CYB2, DLD (LDHD in human), ATP9 (ATP5G1 in human), COQ2, TIM54 (TIMM54 in human), COX4, COX5A, and ATP2 (ATP5B in human). Many other inner membrane proteins are believed to be substrates of the TIMM23 complex.
As inferred from the yeast TOM40:TOM70 complex, the human TOMM40:TOMM70 complex transports precursor proteins from the cytosol, across the outer membrane of the mitochondrion, and into the intermembrane space from where they may be targeted to all locations within the mitochondrion. As inferred from yeast, TOMM40, TOMM22, TOMM5, TOMM6, and TOMM7 probably form the general import pore across the membrane. On the cytosolic side TOMM20 and TOMM22 interact with presequences on mitochondrial precursors while TOMM70 interacts with hydrophobic sequences in mature internal regions of mitochondrial proteins. In yeast, experimentally verified substrates of the TOM40:TOM70 complex include ATP1 (ATP5A1 in human), ATP2 (ATP5B in human), ATP9 (ATP5G1 in human), TOM40 (TOMM40 in human), SSC1 (mtHsp70, HSPA9 in human), CIT1 (CS in human), ACO1 (ACO2 in human), IDH1 (IDH3G in human), BCS1 (BCS1L in human), CYT1 (CYC1 in human), TIM54 (TIMM54 in human), TIM22 (TIMM22 in human), AAC (ADP/ATP translocase 1, ANT, SLC25A4 in human), HSP60, and CYB2. In humans, TOMM40 has been shown to be a substrate (Humphries et al. 2005). In yeast some proteins such as ACO1, ATP1, CIT1, IDH1, and ATP2 contain both presequences that interact with TOM20 and mature regions that interact with TOM70 (Yamamoto et al. 2009). Most proteins imported into mitochondria are anticipated to be transported through the TOMM40:TOMM70 complex.
As inferred from the yeast TIM23 complex, the human TIMM23 complex transports precursor proteins across the inner membrane and into the matrix. As in yeast, subunits TIMM50, TIMM17, and TIMM23 are probably necessary for initiating translocation while the PAM complex with mtHSP70 (HSPA9, yeast SSC1) provides the motive force that drives the transport. mtHSP70 binding to the precursor pulls the protein into the matrix in a reaction requiring ATP hydrolysis. The yeast reaction appears to use a Brownian ratchet mechanism (Yamano et al. 2008). In yeast experimentally verified substrates of TIM23 PAM include Hsp60 (HSP60 in human) and Yfh1 (Frataxin, FXN in human). Many other matrix proteins are believed to be substrates of the TIMM23 complex
TIMM9:TIMM10 with bound substrate protein interacts with FXC1 (TIMM9B, TIMM10B) and TIMM22 at the inner membrane (Muhlenbein et al. 2004). It is believed that TIMM22 then inserts the protein into the inner membrane and TIMM9:TIMM10 and FXC1 are released.
As inferred from the yeast TIM9:TIM10 complex, the human TIMM9:TIMM10:FXC1 complex chaperones hydrophobic membrane proteins in the intermembrane space until their insertion into the inner or outer membrane. Whereas the yeast TIM9:TIM10 complex is soluble in the intermembrane space, the human TIMM9:TIMM10 complex is associated with the outer surface of the inner membrane (Muhlebein et al. 2004). Experimentally verified substrates of the yeast TIM9:TIM10 complex include AAC (ADP/ATP translocase 1, ANT, SLC25A4 in human), TIM17 (TIMM17 in human), TOM40 (TOMM40 in human), TIM23 (TIMM23 in human), TIM22 (TIMM22 in human), and Tafazzin (Tafazzin, TAZ in human). Many other mitochondrial proteins are anticipated to be chaperoned by the TIMM9:TIMM10 complex.
As inferred from the yeast SAM50 complex, the human SAMM50 Complex (SAM50 complex, TOB55 complex) inserts mainly beta-barrel proteins into the outer membrane after they have passed from the cytosol, through the TOMM40:TOMM70 complex, and into the intermembrane space. In yeast, experimentally verified substrates of the SAM50 complex include TOM40 (TOMM40 in human), MDM10, Porin1 (VDAC1 in human), and TOM22 (TOMM22 in human). In humans, TOMM40 (Humphries et al. 2005) and VDAC1 (Kozjak-Pavlovic et al. 2007, homologous to yeast Porin1) have been shown to be substrates. Many other mitochondrial proteins are anticipated to be substrates of the SAMM50 complex.
As inferred from yeast, the alpha subunit of the mitochondrial processing peptidase (MPP) binds presequences of mitochondrial precursors and the beta subunit cleaves the presequence. After cleavage, proteins destined for the matrix are drawn into the matrix by ATP-dependent interaction with mtHSP70 (HSPA9, homolog of yeast SSC1) of the PAM complex.
As inferred from yeast, the alpha subunit of the mitochondrial processing peptidase (MPP) binds presequences of mitochondrial precursors and the beta subunit cleaves the presequence. After cleavage, proteins destined for the inner membrane are released laterally from TIMM23 SORT into the membrane.
As inferred from the yeast TIM22 complex, human TIMM22 inserts precursor proteins into the inner membrane of the mitochondrion. The precursors are hydrophobic and may be chaperoned to TIMM22 by small TIM proteins (TIMM10, TIMM12) of the intermembrane space. In yeast, experimentally verified substrates of the TIM22 complex include AAC (ADP/ATP translocase 1, ANT, SLC25A4 in human), PIC, TIM22 (TIMM22 in human), and TIM23 (TIMM23 in human). Many other inner membrane proteins are anticipated to be substrates ofthe TIMM22 complex.
As inferred from the yeast TIM23 complex, the human TIMM23 complex resides in the inner membrane of the mitochondrion and transfers precursor proteins to the matrix. The TIMM23 complex appears to adopt different configurations (and perhaps different subunit compositions) depending on whether the substrate is destined for the inner membrane or the matrix. Here we refer to the TIMM23 PAM complex as the configuration that delivers inner membrane proteins. The PAM17 subcomplex is required for this activity. The N-terminal presequence of precursors first interacts with TIMM50 and TIMM23. The TIMM17 and TIMM23 subunits form a channel and are required to initiate translocation of precursors. In yeast experimentally verified substrates of TIM23:PAM include Hsp60 (HSP60 in human) and Yfh1 (Frataxin, FXN in human). Many other matrix proteins are believed to be substrates of the TIMM23 complex.
As inferred from the yeast TIM8:TIM13 complex, the human TIMM8:TIMM13 complex chaperones hydrophobic membrane proteins in the intermembrane space until their insertion into the inner or outer membrane. In yeast experimentally verified substrates of the TIM8:TIM13 complex include TIM23 (TIMM23 in human) and TOM40 (TOMM40 in human). Many other mitochondrial proteins are anticipated to be chaperoned by the TIMM8:TIMM13 complex.
As inferred from the yeast MIA40:ERV1 complex, human CHCHD4 (MIA40 homolog) catalyzes the oxidation of cysteine residues in precursor proteins in the intermembrane space to form cystine bonds. The electrons from the cysteine residues are transferred to CHCHD4, then to GFER (ERV1 homolog), and eventually to the respiratory chain. The interaction between yeast MIA40 and ERV1 is transitory. In yeast, experimentally verified substrates of MIA40:ERV1 include COX17, COX19, CMC2, CMC3, CMC4, TIM13 (TIMM13 in human), TIM9 (TIMM9 in human), TIM10 (TIMM10 in human), CCS1 (CCS in human), TIM8 (TIMM8 in human), and ERV1 (GFER in human). Many other mitochondrial proteins are anticipated to be substrates of the MIA40:ERV1 complex.
After passage across the outer membrane, proteins may be targeted to the outer membrane via the SAMM50 complex, to the inner membrane via the TIMM22 or TIMM23 complexes (reviewed in van der Laan et al. 2010), to the matrix via the TIMM23 complex (reviewed in van der Laan et al. 2010), or proteins may fold and remain in the intermembrane space (reviewed in Stojanovski et al. 2008, Deponte and Hell 2009, Sideris and Tokatlidis 2010). Presequences on matrix and inner membrane proteins cause interaction with TIMM23 complexes; internal targeting sequences cause outer membrane proteins to interact with the SAMM50 complex and inner membrane proteins to interact with the TIMM22 complex. While in the intermembrane space hydrophobic proteins are chaperoned by the TIMM8:TIMM13 complex and/or the TIMM9:TIMM10:FXC1 complex.
Original Pathway at Reactome: http://www.reactome.org/PathwayBrowser/#DB=gk_current&FOCUS_SPECIES_ID=48887&FOCUS_PATHWAY_ID=1268020
Try the New WikiPathways
View approved pathways at the new wikipathways.org.Quality Tags
Ontology Terms
Bibliography
History
External references
DataNodes
TIMM13
ProteinTIMM10 FXC1 TIM22
ProteinTIMM10
ProteinAnnotated Interactions
In yeast experimentally verified substrates of the TIM23 complex targeted to the inner membrane include CYB2, DLD (LDHD in human), ATP9 (ATP5G1 in human), COQ2, TIM54 (TIMM54 in human), COX4, COX5A, and ATP2 (ATP5B in human). Many other inner membrane proteins are believed to be substrates of the TIMM23 complex.
In yeast experimentally verified substrates of the TIM23 SORT complex targeted to the inner membrane include CYB2, DLD (LDHD in human), ATP9 (ATP5G1 in human), COQ2, TIM54 (TIMM54 in human), COX4, COX5A, and ATP2 (ATP5B in human). Many other inner membrane proteins are believed to be substrates of the TIMM23 complex.
In yeast, experimentally verified substrates of the TOM40:TOM70 complex include ATP1 (ATP5A1 in human), ATP2 (ATP5B in human), ATP9 (ATP5G1 in human), TOM40 (TOMM40 in human), SSC1 (mtHsp70, HSPA9 in human), CIT1 (CS in human), ACO1 (ACO2 in human), IDH1 (IDH3G in human), BCS1 (BCS1L in human), CYT1 (CYC1 in human), TIM54 (TIMM54 in human), TIM22 (TIMM22 in human), AAC (ADP/ATP translocase 1, ANT, SLC25A4 in human), HSP60, and CYB2. In humans, TOMM40 has been shown to be a substrate (Humphries et al. 2005). In yeast some proteins such as ACO1, ATP1, CIT1, IDH1, and ATP2 contain both presequences that interact with TOM20 and mature regions that interact with TOM70 (Yamamoto et al. 2009). Most proteins imported into mitochondria are anticipated to be transported through the TOMM40:TOMM70 complex.
In yeast experimentally verified substrates of TIM23 PAM include Hsp60 (HSP60 in human) and Yfh1 (Frataxin, FXN in human). Many other matrix proteins are believed to be substrates of the TIMM23 complex
Experimentally verified substrates of the yeast TIM9:TIM10 complex include AAC (ADP/ATP translocase 1, ANT, SLC25A4 in human), TIM17 (TIMM17 in human), TOM40 (TOMM40 in human), TIM23 (TIMM23 in human), TIM22 (TIMM22 in human), and Tafazzin (Tafazzin, TAZ in human). Many other mitochondrial proteins are anticipated to be chaperoned by the TIMM9:TIMM10 complex.
In yeast, experimentally verified substrates of the SAM50 complex include TOM40 (TOMM40 in human), MDM10, Porin1 (VDAC1 in human), and TOM22 (TOMM22 in human). In humans, TOMM40 (Humphries et al. 2005) and VDAC1 (Kozjak-Pavlovic et al. 2007, homologous to yeast Porin1) have been shown to be substrates. Many other mitochondrial proteins are anticipated to be substrates of the SAMM50 complex.
In yeast experimentally verified substrates of TIM23:PAM include Hsp60 (HSP60 in human) and Yfh1 (Frataxin, FXN in human). Many other matrix proteins are believed to be substrates of the TIMM23 complex.
In yeast, experimentally verified substrates of MIA40:ERV1 include COX17, COX19, CMC2, CMC3, CMC4, TIM13 (TIMM13 in human), TIM9 (TIMM9 in human), TIM10 (TIMM10 in human), CCS1 (CCS in human), TIM8 (TIMM8 in human), and ERV1 (GFER in human). Many other mitochondrial proteins are anticipated to be substrates of the MIA40:ERV1 complex.
TIMM10
Protein