Affinage

TOMM7

Mitochondrial import receptor subunit TOM7 homolog · UniProt Q9P0U1

Length
55 aa
Mass
6.2 kDa
Annotated
2026-06-10
17 papers in source corpus 13 papers cited in narrative 13 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

TOMM7 encodes a small tail-anchored integral membrane subunit of the TOM translocase of the mitochondrial outer membrane that exerts a dynamic, predominantly destabilizing regulatory influence on preprotein import (PMID:8641278). Anchored in the outer membrane via a C-terminal transmembrane segment whose conserved proline is required for targeting, Tom7 makes direct contact with the import pore Tom40 (PMID:11278536, PMID:11943179, PMID:21036907). Within the TOM core it acts antagonistically to the stabilizing subunits Tom5 and Tom6: its loss stabilizes receptor–pore interactions among Tom20, Tom22, and Tom40 and impairs two-step import as well as outer-membrane porin biogenesis (PMID:8641278, PMID:21059357). Tom7 also coordinates beta-barrel protein assembly by recruiting and sequestering free Mdm10, promoting its dissociation from the SAM/TOB complex to control the timing of Tom40 release and the late assembly of Tom22, thereby tuning the maturation of both Tom40 and porin (PMID:16760475, PMID:21036907, PMID:21059357). In the regulation of mitochondrial quality control, Tom7 is specifically required to arrest PINK1 at the outer membrane upon depolarization, opposing OMA1-mediated PINK1 cleavage in a regulated balance that governs PINK1/Parkin-dependent mitophagy [PMID:30733118, PMID:bio_10.1101_2025.06.10.658840]. Biallelic loss-of-function variants in human TOMM7 cause an autosomal recessive progeroid syndrome and syndromic short stature accompanied by altered mitochondrial protein import and bioenergetic uncoupling (PMID:36282599, PMID:36299998).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 1996 High

    Established Tom7 as a TOM translocase subunit and, unexpectedly, as a destabilizing element whose loss tightens receptor–pore contacts and impairs import — defining a regulatory rather than purely structural role.

    Evidence Yeast deletion/double-mutant genetics, blue native PAGE, and in vitro import assays

    PMID:8641278

    Open questions at the time
    • Did not resolve the direct molecular contacts of Tom7
    • Mechanism distinguishing Tom7 from the stabilizing Tom6 not defined at residue level
  2. 2001 High

    Demonstrated that Tom7 physically contacts Tom40 and assembles into authentic TOM complexes, anchoring its regulatory role to a direct interaction with the import pore.

    Evidence In vivo cross-linking and in vitro import/assembly assays in Neurospora crassa

    PMID:11278536

    Open questions at the time
    • Which segment of Tom7 mediates Tom40 contact not yet mapped
  3. 2002 Medium

    Defined Tom7 as a tail-anchored protein whose C-terminal transmembrane segment, including a conserved proline, carries outer-membrane targeting information, and showed the human protein assembles via a Tom40-containing intermediate into the mature TOM complex.

    Evidence Truncation/proline mutagenesis with microscopy in yeast; HeLa mitochondrial import, BN-PAGE and antibody supershift for the human protein

    PMID:11943179 PMID:12198123

    Open questions at the time
    • Single-lab targeting analysis
    • Rate-limiting role of Tom22 in human assembly not connected to Tom7's regulatory functions
  4. 2006 High

    Revealed that Tom7 acts antagonistically to Mdm10 in beta-barrel biogenesis, segregating Mdm10 from the SAM(holo) complex to selectively restrain Tom40 versus porin assembly.

    Evidence Yeast TOM7 deletion, BN-PAGE, in vitro assembly assays and co-immunoprecipitation

    PMID:16760475

    Open questions at the time
    • Direct physical basis of Tom7–Mdm10 interaction not yet shown
  5. 2010 High

    Mapped Tom7's direct contacts to Tom40 (via its transmembrane segment) and Mdm10 by site-specific photocross-linking, and resolved two distinct inhibitory steps — early antagonism of Tom5/Tom6 and late promotion of SAM–Mdm10 dissociation delaying Tom22 assembly.

    Evidence Site-specific in vivo photocross-linking, depletion/overexpression, BN-PAGE and in vitro import in yeast

    PMID:21036907 PMID:21059357

    Open questions at the time
    • Structural model of these transient assembly intermediates absent
    • How the two steps are temporally coordinated not defined
  6. 2018 Medium

    Linked Tom7 to vascular biology by showing its deficit increases mitochondrial Rac1 import and redox signaling, with endothelial rescue correcting cerebrovascular malformation.

    Evidence Zebrafish screen, conditional knockout mice, endothelial transgenic rescue and import assays

    PMID:30354240

    Open questions at the time
    • Mechanism by which Tom7 restricts Rac1 import unresolved
    • Single lab; relation to canonical TOM regulatory role unclear
  7. 2019 High

    Identified Tom7 as the factor required to arrest PINK1 at the outer membrane upon depolarization, defining a regulated balance with OMA1 that gates PINK1/Parkin mitophagy.

    Evidence Tom7 knockout cells, PINK1 motif mutagenesis, OMA1 suppression and protease-protection assays

    PMID:30733118

    Open questions at the time
    • Structural basis of how Tom7 retains PINK1 not resolved
    • Whether this uses the same Tom40 contacts as import regulation unknown
  8. 2022 Medium

    Connected biallelic TOMM7 loss-of-function to human disease — a progeroid syndrome and syndromic short stature — with patient cells and mouse models showing altered import and oxidation/ATP-synthesis uncoupling.

    Evidence Exome sequencing, mitochondrial proteomics and respirometry in patient fibroblasts; mouse knock-in/knockout bioenergetics

    PMID:36282599 PMID:36299998

    Open questions at the time
    • No reconstitution or variant rescue in the progeroid family
    • Mechanistic link from import defect to bioenergetic uncoupling not established
  9. 2025 Medium

    Extended the mitophagy role to disease contexts, showing TOMM7 modulates PINK1/Parkin mitophagy in kidney tubular cells via PLA2G6 redistribution and in human dopaminergic neurons via ubiquitin pSer65, and is transcriptionally repressed by ZBTB12.

    Evidence Tomm7 overexpression in db/db mice, HK-2 cell assays, PLA2G6 fractionation, ChIP; CRISPR knockout in iPSC-derived dopaminergic neurons (preprint)

    PMID:41276015 PMID:bio_10.1101_2025.06.10.658840

    Open questions at the time
    • Direct molecular link between Tom7 and PLA2G6 trafficking unclear
    • Neuronal data are preprint and single-lab
    • ZBTB12 regulation not connected to physiological mitophagy triggers

Open questions

Synthesis pass · forward-looking unresolved questions
  • How Tom7's single transmembrane contact with Tom40 simultaneously supports its destabilizing role in import, its Mdm10-dependent assembly regulation, and its PINK1 retention function remains unresolved at a structural and mechanistic level.
  • No structure of Tom7 within the human TOM complex bound to PINK1
  • Whether import-regulatory and mitophagy-gating activities are separable not tested

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 4 GO:0005198 structural molecule activity 3
Pathway
R-HSA-392499 Metabolism of proteins 3 R-HSA-9612973 Autophagy 3 R-HSA-9609507 Protein localization 2
Complex memberships
TOM complex

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1996 Tom7 is an integral membrane subunit of the mitochondrial outer membrane TOM translocase. Deletion of TOM7 inhibits import of the outer membrane protein porin and strongly impairs two-step preprotein import into the mitochondrial interior. Loss of Tom7 stabilizes interactions between receptors Tom20 and Tom22 and the import pore Tom40, indicating Tom7 exerts a destabilizing effect on part of the outer membrane translocase, while Tom6 stabilizes these interactions. Genetic synthetic growth defects of tom7Δ tom20Δ and tom7Δ tom6Δ double mutants confirmed functional relationships between Tom7, Tom20, and Tom6. Yeast genetics (deletion mutants, double mutants), blue native PAGE, import assays in vitro, biochemical fractionation The EMBO journal High 8641278
2001 Tom6 and Tom7 are subunits of the Neurospora crassa TOM core complex. Cross-linking experiments showed both proteins are in direct contact with Tom40. Precursors of Tom6 and Tom7 insert into the outer membrane in vitro and assemble into authentic TOM complexes; assembly shares a common binding site with the general import pathway and requires the integrity of TOM receptor components. Cross-linking in vivo, in vitro import/assembly assays, blue native PAGE, hybrid protein analysis The Journal of biological chemistry High 11278536
2002 Tom7 is a tail-anchored protein; the carboxy-terminal 33 amino acids contain the targeting information for the mitochondrial outer membrane. A conserved proline residue within the transmembrane segment is required for efficient targeting of Tom7 to the outer membrane. An equivalent proline residue is important for targeting each of the other three tail-anchored proteins (Tom5, Tom6, Tom22) that associate with Tom40 to form the TOM core. Deletion/truncation analysis, mutagenesis of conserved proline, fluorescence microscopy, import assays FEBS letters Medium 11943179
2002 Human TOMM7 is imported into mitochondria in a nucleotide-independent manner and is anchored to the outer membrane with its C terminus facing the intermembrane space. Human Tom7 assembles first into an ~120 kDa import intermediate containing Tom40 but lacking receptor components, which is then chased to the stable ~380 kDa TOM complex additionally containing Tom22. Tom22 is rate-limiting for TOM complex formation, as Tom22 overexpression accelerates Tom7 assembly into the 380 kDa complex. Import assays in HeLa cell mitochondria, blue native PAGE, supershift analysis with TOM-specific antibodies, Tom22 overexpression The Journal of biological chemistry High 12198123
2006 Tom7 functions in an antagonistic manner to Mdm10 in beta-barrel protein biogenesis. Tom7 promotes segregation of Mdm10 from the SAM(holo) complex into a low molecular mass form. Upon deletion of Tom7, the fraction of Mdm10 in the SAM(holo) complex is significantly increased, selectively promoting Tom40 assembly but not porin assembly. Yeast genetics (TOM7 deletion), blue native PAGE, in vitro import/assembly assays, co-immunoprecipitation The Journal of biological chemistry High 16760475
2010 Tom7 directly interacts with Tom40 through its transmembrane segment and with Mdm10, as shown by site-specific photocross-linking in vivo. Tom7 recruits Mdm10 and enhances its association with the MMM1 complex, thereby regulating the timing of Tom40 release from the TOB/SAM complex for subsequent assembly into the TOM40 complex. Depletion of Tom7 decreased transient accumulation of Tom40 at the TOB complex, while overexpression of Tom7 enhanced it. Site-specific photocross-linking in vivo, in vitro import assays, BN-PAGE, Tom7 depletion and overexpression The Journal of biological chemistry High 21036907
2010 Tom7 plays an inhibitory role at two distinct steps in TOM complex biogenesis: (1) Tom7 acts antagonistically to Tom5 and Tom6 at an early stage of Tom40 assembly at the SAM complex; (2) Tom7 interacts with free Mdm10 (not bound to the SAM complex), thereby promoting dissociation of the SAM-Mdm10 complex and delaying Tom22 assembly with Tom40 at a late stage. Thus Tom7 modulates biogenesis of both the beta-barrel protein Tom40 and the alpha-helical Tom22. Yeast genetics, blue native PAGE, in vitro import assays, co-immunoprecipitation Journal of molecular biology High 21059357
2018 Tomm7 deficit in endothelial cells induces increased import of Rac1 protein into mitochondria and facilitates mitochondrial Rac1-coupled redox signaling, causing angiogenic impairment that underlies cerebrovascular network malformation. Endothelial-specific transgenesis of tomm7 restored cerebrovascular anomalies in Tomm7-knockout mice. Loss-of-function genetic screening in zebrafish, conditional knockout mice, endothelial-specific transgenesis, vascular imaging, mitochondrial protein import assays Arteriosclerosis, thrombosis, and vascular biology Medium 30354240
2019 Tom7 is required for PINK1 accumulation at the outer mitochondrial membrane upon mitochondrial depolarization. Deletion of Tom7 allows PINK1 to be imported into depolarized mitochondria where it is cleaved by the OMA1 protease rather than arrested at the outer membrane. PINK1 contains a negatively charged amino acid cluster motif C-terminal to its transmembrane domain that is required for import arrest; mutagenesis of this motif phenocopies Tom7 deletion. Thus, ΔΨm-loss-dependent PINK1 import arrest involves an actively regulated 'tug of war' between Tom7 (promoting outer membrane retention) and OMA1 (promoting PINK1 cleavage after inner-membrane import). Tom7 knockout cell lines, PINK1 mutagenesis, OMA1 suppression, import assays, protease protection assays, cell biology Molecular cell High 30733118
2022 A homozygous missense variant in TOMM7 (p.Pro29Leu) causes an autosomal recessive progeroid syndrome in a human patient. Proteomic comparison of mitochondria from patient-derived fibroblasts vs. controls revealed increased abundance of oxidative phosphorylation proteins and reduced abundance of phospholipid metabolism proteins, along with elevated basal and maximal oxygen consumption rates, consistent with altered mitochondrial protein import due to biallelic loss-of-function TOMM7. Exome sequencing, mitochondrial proteomics (quantitative MS), oxygen consumption rate measurement in patient-derived fibroblasts The Journal of clinical investigation Medium 36282599
2022 A homozygous hypomorphic variant in TOMM7 (p.Trp25Arg) causes syndromic short stature with mitochondrial dysfunction. Mouse models homozygous for this variant show a milder phenotype than complete Tomm7 deletion mice. Tomm7 deficiency causes an uncoupling between oxidation and ATP synthesis without impairing the ETC or tricarboxylic acid cycle function, as evidenced by increased oxygen consumption with normal responses to ETC inhibitors. Mouse knock-in and knockout models, oxygen consumption assays, ETC inhibitor assays, patient variant analysis HGG advances Medium 36299998
2025 TOMM7 regulates PINK1/Parkin-mediated mitophagy in kidney tubular cells by modulating the intracellular redistribution of phospholipase PLA2G6 between the nucleus and mitochondria. Tomm7 overexpression in db/db mice restored PINK1/Parkin-mediated mitophagy and alleviated kidney injury. ZBTB12 was identified as a transcriptional repressor of TOMM7. Tomm7 overexpression in db/db mice, HK-2 cell overexpression/knockdown, mitophagy flux assays, subcellular fractionation of PLA2G6, ChIP/transcription factor binding assays Kidney international Medium 41276015
2025 CRISPR-Cas9 knockout of TOM7 in iPSC-derived dopaminergic neurons decreased ubiquitin pSer65 upregulation during mitophagy activation (induced by exogenous stimuli), confirming TOM7's role in the PINK1-PARKIN mitophagy pathway in a human neuronal model. High-throughput arrayed CRISPR-Cas9 KO screen in iPSC-derived dopaminergic neurons, high-content immunofluorescence imaging, machine learning analysis bioRxivpreprint Medium bio_10.1101_2025.06.10.658840

Source papers

Stage 0 corpus · 17 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2019 Reciprocal Roles of Tom7 and OMA1 during Mitochondrial Import and Activation of PINK1. Molecular cell 145 30733118
1996 Tom7 modulates the dynamics of the mitochondrial outer membrane translocase and plays a pathway-related role in protein import. The EMBO journal 137 8641278
2002 Insertion and assembly of human tom7 into the preprotein translocase complex of the outer mitochondrial membrane. The Journal of biological chemistry 114 12198123
2010 Tom7 regulates Mdm10-mediated assembly of the mitochondrial import channel protein Tom40. The Journal of biological chemistry 88 21036907
2006 Mitochondrial protein sorting: differentiation of beta-barrel assembly by Tom7-mediated segregation of Mdm10. The Journal of biological chemistry 87 16760475
2010 Biogenesis of mitochondria: dual role of Tom7 in modulating assembly of the preprotein translocase of the outer membrane. Journal of molecular biology 76 21059357
2001 Assembly of Tom6 and Tom7 into the TOM core complex of Neurospora crassa. The Journal of biological chemistry 55 11278536
2002 A conserved proline residue is present in the transmembrane-spanning domain of Tom7 and other tail-anchored protein subunits of the TOM translocase. FEBS letters 42 11943179
2022 Autosomal recessive progeroid syndrome due to homozygosity for a TOMM7 variant. The Journal of clinical investigation 24 36282599
2018 Endothelial Mitochondrial Preprotein Translocase Tomm7-Rac1 Signaling Axis Dominates Cerebrovascular Network Homeostasis. Arteriosclerosis, thrombosis, and vascular biology 18 30354240
2022 A hypomorphic variant in the translocase of the outer mitochondrial membrane complex subunit TOMM7 causes short stature and developmental delay. HGG advances 16 36299998
2018 TOM7 silencing exacerbates focal cerebral ischemia injury in rat by targeting PINK1/Beclin1-mediated autophagy. Behavioural brain research 12 30468788
2025 Mitochondrial protein TOMM7 alleviates diabetic kidney disease by regulating mitophagy via intracellular redistribution of phospholipase PLA2G6. Kidney international 3 41276015
2015 [Association of genetic variants in TOMM7 gene and gene environment interaction with type 2 diabetes in Chinese Dong population]. Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences 3 25652373
2026 Single-cell and Bulk RNA-Seq Analyses Reveal TOMM7-mediated Multi-cell Death Mechanisms Driving Muscle-invasive Bladder Cancer Progression. Recent patents on anti-cancer drug discovery 0 41540546
2025 Growth Hormone Response in a Child With a Homozygous TOMM7 Mutation: Novel Therapeutic Insights. The American journal of case reports 0 41460760
2005 Cloning and characterization of TOM7-like gene in wheat. Yi chuan xue bao = Acta genetica Sinica 0 15759864

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