TOM complex
tom_somatic_complex
Participant: Protein Complex: TOM complex
Protein Complex:
Mitochondrial protein import machinery in Drosophila melanogaster
Most mitochondrial proteins are made on cytosolic ribosomes and imported post-translationally. Nearly all enter through the TOM complex of the outer membrane, whose channel is formed by Tom40. Beta-barrel outer membrane proteins are then handed by the small TIM chaperones of the intermembrane space to the SAM complex for insertion. Carrier-type inner membrane proteins are inserted by the TIM22 complex, and presequence-bearing precursors are translocated by the TIM23 complex, driven into the matrix by the presequence translocase-associated motor (PAM) built around mitochondrial Hsp70 (Hsc70-5). Matrix presequences are removed by the mitochondrial processing peptidase, and some intermembrane space-sorted precursors are further cleaved by the inner membrane peptidase. Cysteine-rich intermembrane space proteins are imported and oxidatively folded by the Mia40-Alr disulfide relay. Drosophila has testis-specific paralogs of several subunits (for example tomboy40, tomboy20 and several Tim17 and Tim50 paralogs).
mitochondrial protein import pathwayGO:7770058
FB:FBgg0001904
FlyBase gene group MPT: Mitochondrial protein import complexes
FlyBase release FB2026_03 groups 32 D. melanogaster genes as mitochondrial protein import complexes (MPT); this module models that group.
FB:FBgg0001907
FlyBase gene group TIMM23: Tim23 translocase of inner mitochondrial membrane complex subunits
FlyBase release FB2026_03 groups 18 D. melanogaster genes as tim23 translocase of inner mitochondrial membrane complex subunits (TIMM23); this module models that group.
FB:FBgg0002013
FlyBase gene group MDRS: Mitochondrial disulfide relay system
FlyBase release FB2026_03 groups 3 D. melanogaster genes as mitochondrial disulfide relay system (MDRS); this module models that group.
FB:FBgg0002140
FlyBase gene group MPP: Mitochondrial processing peptidase complex
FlyBase release FB2026_03 groups 2 D. melanogaster genes as mitochondrial processing peptidase complex (MPP); this module models that group.
FB:FBgg0002141
FlyBase gene group IMP: Mitochondrial inner membrane peptidase complex
FlyBase release FB2026_03 groups 2 D. melanogaster genes as mitochondrial inner membrane peptidase complex (IMP); this module models that group.
GO:7770058
mitochondrial protein import pathway
GO term grounding the module as mitochondrial protein import pathway.
Boundary. The module covers the FlyBase import complexes (MPT), the TIM23 subunit families (TIMM23), the disulfide relay (MDRS) and the two presequence peptidases (MPP, IMP). Cytosolic chaperones and mitochondrial quality-control proteases are outside. The Tim9-Tim10 chaperones appear both in the small TIM part and, following FlyBase, in the TIM22 complex. Paralogs listed by FlyBase in the Tim17, Tim50 and Tim16 families are kept as separate annotons; which of them function in somatic versus testis TIM23 complexes is only partly established. FlyBase groups realized by this module: MPT (FBgg0001904), TIMM23 (FBgg0001907), MDRS (FBgg0002013), MPP (FBgg0002140), IMP (FBgg0002141). Subgroups folded into it: TOMM-C, TOMM-T, TOMM, TIMM22, PAM, TIMM23C, TIMM17, TIM23F, TIM23SSU, TIM50F, TIMS, TIM813-U, TIM813-T, TIM23-SORT, TIM23-MOTOR, SAM-U, SAM-T, TIM910, TIM-3SU. Participants were generated from the FlyBase gene-group membership and mapped to UniProtKB by projects/FLYBASE_GENE_GROUPS/generate_modules.py from module_specs/dmel_mitochondrial_protein_import.yaml. None of the member genes has a gene review in this repository yet.
21Nodes
12Parts
3Variant Sets
8Variants
32Annotons
7Connections
Derived QC
Recommended-field compliance
100.0%
recommended fields populated
All recommended fields populated.
Module deep research
✗ none found
No MODULE:dmel_mitochondrial_protein_import deep-research report alongside the module YAML.
Leaf nodes lacking representative members
✓ every leaf node grounds to a representative protein.
Template conformance
✓ every declared conforms_to bundle matches its template motif.
Reaction chaining (advisory)
✓ every PRECEDES step chains, or its break is acknowledged via chaining_status.
- tom_complex → small_tim_chaperones [NOT_CHECKED]
- small_tim_chaperones → sam_complex [NOT_CHECKED]
- small_tim_chaperones → tim22_complex [NOT_CHECKED]
- tom_complex → tim23_complex [NOT_CHECKED]
- tom_complex → disulfide_relay [NOT_CHECKED]
- tim23_complex → mpp [NOT_CHECKED]
- mpp → imp [NOT_CHECKED]
Function consistency and core coverage
0 gene-function check(s) reflected in core functions · 0 conflict(s) · 3 evidence or coverage gap(s) (4 comparison(s))
Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.
| Annoton | Participant | Function | Assessment |
|---|---|---|---|
| pam_motor_hsc70_5 | Hsc70-5 UniProtKB:P29845 Gene |
ATP-dependent protein folding chaperone GO:0140662 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| pam_motor_roe1 | Roe1 UniProtKB:P48604 Gene |
adenyl-nucleotide exchange factor activity GO:0000774 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| disulfide_relay_alr | Alr UniProtKB:Q7KUU5 Gene |
thiol oxidase activity GO:0016972 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| mpp_complex | PROTEIN_COMPLEX Gene |
metalloendopeptidase activity GO:0004222 |
Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews. |
Gene-review completeness (0/47 grounded genes reviewed)
0 complete review(s) · 0 with deep research · 47 missing review · 0 reviewed but lacking deep research
| Gene | Review | Complete | Deep research |
|---|---|---|---|
| tomboy40 A1Z6L1 | ✗ | — | — |
| Mppa A1Z771 | ✗ | — | — |
| Tom7 A1Z7L7 | ✗ | — | — |
| Immp2 A1ZBX2 | ✗ | — | — |
| Tom6 A8DY45 | ✗ | — | — |
| Tom20 M9PFQ5 | ✗ | — | — |
| Hsc70-5 P29845 | ✗ | — | — |
| Roe1 P48604 | ✗ | — | — |
| CG34132 Q0E8V7 | ✗ | — | — |
| Tim23 Q5LJU3 | ✗ | — | — |
| Alr Q7KUU5 | ✗ | — | — |
| Tim17b Q7PLT4 | ✗ | — | — |
| CG31229 Q8IN78 | ✗ | — | — |
| Tom5 Q8IRD0 | ✗ | — | — |
| Tom40 Q9U4L6 | ✗ | — | — |
| CG7639 Q9V784 | ✗ | — | — |
| ttm3 Q9V9P3 | ✗ | — | — |
| Mia40 Q9VAA6 | ✗ | — | — |
| CG11779 Q9VDZ7 | ✗ | — | — |
| blp Q9VF08 | ✗ | — | — |
| UQCR-C1 Q9VFF0 | ✗ | — | — |
| Tim17a1 Q9VGA2 | ✗ | — | — |
| tomboy20 Q9VGX9 | ✗ | — | — |
| CG9393 Q9VHB6 | ✗ | — | — |
| Tim17b2 Q9VJP1 | ✗ | — | — |
| Tom70 Q9VKC8 | ✗ | — | — |
| Mulk Q9VL10 | ✗ | — | — |
| CG7382 Q9VMR0 | ✗ | — | — |
| Tim17a2 Q9VN97 | ✗ | — | — |
| Tim17b1 Q9VNA0 | ✗ | — | — |
| AIF Q9VQ79 | ✗ | — | — |
| CG1724 Q9VRF6 | ✗ | — | — |
| CG7394 Q9VTJ8 | ✗ | — | — |
| Tim13 Q9VTN3 | ✗ | — | — |
| CG6878 Q9VUM2 | ✗ | — | — |
| Mtx2 Q9VW58 | ✗ | — | — |
| Immp1 Q9VXR8 | ✗ | — | — |
| Tim9a Q9VYD7 | ✗ | — | — |
| mge Q9VZL1 | ✗ | — | — |
| ttm2 Q9W0S3 | ✗ | — | — |
| Tim10 Q9W2D6 | ✗ | — | — |
| CG1409 Q9W3P5 | ✗ | — | — |
| Timm29 Q9W4R8 | ✗ | — | — |
| ttm50 Q9W4V8 | ✗ | — | — |
| Tim9b Q9Y0V3 | ✗ | — | — |
| Tim8 Q9Y1A3 | ✗ | — | — |
| CG5662 X2JDU8 | ✗ | — | — |
Details
Context
Drosophila melanogasterNCBITaxon:7227
Mitochondrial protein importBiological Processdmel_mitochondrial_protein_import
Outer membrane, intermembrane space and inner membrane translocases, the import motor, disulfide relay and presequence peptidases that import nuclear-encoded proteins into mitochondria.
mitochondrial protein import pathwayGO:7770058
Context
Drosophila melanogasterNCBITaxon:7227
Connections
Hydrophobic precursors pass from the TOM channel to the small TIM chaperones.
Small TIMs deliver beta-barrel precursors to SAM.
Small TIMs deliver carrier precursors to TIM22.
Presequence precursors pass from TOM to TIM23.
Cysteine-rich precursors cross TOM and are trapped by Mia40.
Presequences reaching the matrix are cleaved by MPP.
Part 1: outer membrane entry gate
TOM complexBiological Processtom_complex
Translocase of the outer membrane. FlyBase defines a somatic complex and a testis-specific variant that uses the paralogs tomboy40 and tomboy20.
mitochondrial outer membrane translocase complexGO:0005742
Variant set: Somatic or testis TOM complex (One Or More)
TOM complexBiological Processtom_somatic
Annotons
TOM complex testis-specific variantBiological Processtom_testis
Annotons
TOM complex testis-specific variant
tom_testis_complex
Participant: Protein Complex: TOM complex testis-specific variant
Protein Complex:
Part 2: intermembrane space chaperones for hydrophobic precursors
Intermembrane space small TIM chaperonesBiological Processsmall_tim_chaperones
Hexameric small TIM complexes that escort hydrophobic precursors across the intermembrane space to the SAM and TIM22 complexes. FlyBase defines Tim9-Tim10 complexes (with or without Tim9b) and Tim8-Tim13 complexes (Tim8 with CG34132 or with the testis-specific Tim13).
Variant set: Small TIM complexes (One Or More)
Tim9-Tim10 complexBiological Processtim9_tim10
Annotons
Tim9-Tim10 complex
tim9_tim10_complex
Participant: Protein Complex: Tim9-Tim10 complex
Protein Complex:
Tim9a-Tim10-Tim9b complexBiological Processtim9a_tim10_tim9b
Annotons
Tim9a-Tim10-Tim9b complex
tim9a_tim10_tim9b_complex
Participant: Protein Complex: Tim9a-Tim10-Tim9b complex
Protein Complex:
Tim8-Tim13 complex CG34132 variantBiological Processtim8_cg34132
Annotons
Tim8-Tim13 complex CG34132 variant
tim8_cg34132_complex
Participant: Protein Complex: Tim8-Tim13 complex CG34132 variant
Protein Complex:
Tim8-Tim13 complex testis variantBiological Processtim8_tim13_testis
Annotons
Tim8-Tim13 complex testis variant
tim8_tim13_testis_complex
Participant: Protein Complex: Tim8-Tim13 complex testis variant
Protein Complex:
Part 3: beta-barrel insertion into the outer membrane
SAM complexBiological Processsam_complex
Sorting and assembly machinery built on the beta-barrel protein CG7639 (Sam50) with metaxins. FlyBase defines a Mtx2 variant and a CG5662 variant.
Variant set: SAM complex variants (One Or More)
SAM complex Mtx2 variantBiological Processsam_mtx2
Annotons
SAM complex Mtx2 variant
sam_mtx2_complex
Participant: Protein Complex: SAM complex Mtx2 variant
Protein Complex:
Processes
protein insertion into mitochondrial outer membraneGO:0045040
SAM complex CG5662 variantBiological Processsam_cg5662
Annotons
SAM complex CG5662 variant
sam_cg5662_complex
Participant: Protein Complex: SAM complex CG5662 variant
Protein Complex:
Processes
protein insertion into mitochondrial outer membraneGO:0045040
Part 4: carrier protein insertion into the inner membrane
TIM22 complexBiological Processtim22_complex
Carrier translocase of the inner membrane formed by Tim22 (CG31229) with Tim29, the acylglycerol kinase Mulk and the Tim9-Tim10 chaperones.
Annotons
TIM22 complex
tim22_complex_complex
Participant: Protein Complex: TIM22 complex
Protein Complex:
Processes
protein insertion into mitochondrial inner membraneGO:0045039
Part 5: presequence protein translocation across the inner membrane
TIM23 presequence translocase and import motorBiological Processtim23_complex
The TIM23 complex translocates presequence-bearing precursors across or into the inner membrane. FlyBase lists every paralog of the Tim17, Tim23 and Tim50 families; the canonical somatic complex uses Tim17b, Tim23 and ttm50, whereas several other paralogs are testis-enriched. Paralog sets are modelled one annoton per gene because they are alternatives, not co-subunits.
TIM23 mitochondrial import inner membrane translocase complexGO:0005744
Part 1: channel-forming core
Tim17 and Tim23 family channel subunitsBiological Processtim23_channel
Annotons
CG1724 Tim17 and Tim23 family channel subunits
tim23_channel_cg1724
Participant: Gene Product: CG1724
Gene Product:
CG1724UniProtKB:Q9VRF6
Processes
protein import into mitochondrial matrixGO:0030150
Tim17a1 Tim17 and Tim23 family channel subunits
tim23_channel_tim17a1
Participant: Gene Product: Tim17a1
Gene Product:
Tim17a1UniProtKB:Q9VGA2
Processes
protein import into mitochondrial matrixGO:0030150
Tim17a2 Tim17 and Tim23 family channel subunits
tim23_channel_tim17a2
Participant: Gene Product: Tim17a2
Gene Product:
Tim17a2UniProtKB:Q9VN97
Processes
protein import into mitochondrial matrixGO:0030150
Tim17b Tim17 and Tim23 family channel subunits
tim23_channel_tim17b
Participant: Gene Product: Tim17b
Gene Product:
Tim17bUniProtKB:Q7PLT4
Processes
protein import into mitochondrial matrixGO:0030150
Tim17b1 Tim17 and Tim23 family channel subunits
tim23_channel_tim17b1
Participant: Gene Product: Tim17b1
Gene Product:
Tim17b1UniProtKB:Q9VNA0
Processes
protein import into mitochondrial matrixGO:0030150
Tim17b2 Tim17 and Tim23 family channel subunits
tim23_channel_tim17b2
Participant: Gene Product: Tim17b2
Gene Product:
Tim17b2UniProtKB:Q9VJP1
Processes
protein import into mitochondrial matrixGO:0030150
Tim23 Tim17 and Tim23 family channel subunits
tim23_channel_tim23
Participant: Gene Product: Tim23
Gene Product:
Tim23UniProtKB:Q5LJU3
Processes
protein import into mitochondrial matrixGO:0030150
Part 2: intermembrane space presequence receptor
Tim50 presequence receptorsBiological Processtim50_receptors
Annotons
ttm2 Tim50 presequence receptors
tim50_receptors_ttm2
Participant: Gene Product: ttm2
Gene Product:
ttm2UniProtKB:Q9W0S3
ttm3 Tim50 presequence receptors
tim50_receptors_ttm3
Participant: Gene Product: ttm3
Gene Product:
ttm3UniProtKB:Q9V9P3
ttm50 Tim50 presequence receptors
tim50_receptors_ttm50
Participant: Gene Product: ttm50
Gene Product:
ttm50UniProtKB:Q9W4V8
Part 3: accessory subunits (Tim21 and Mgr2/ROMO1)
TIM23 accessory subunitsBiological Processtim23_accessory
Annotons
CG6878 TIM23 accessory subunits
tim23_accessory_cg6878
Participant: Gene Product: CG6878
Gene Product:
CG6878UniProtKB:Q9VUM2
CG7382 TIM23 accessory subunits
tim23_accessory_cg7382
Participant: Gene Product: CG7382
Gene Product:
CG7382UniProtKB:Q9VMR0
Part 4: ATP-driven import motor
Presequence translocase-associated motorBiological Processpam_motor
Tim44 (CG11779) tethers mitochondrial Hsp70 (Hsc70-5) to the channel; the J-protein Tim14 (CG7394) with its partner Tim16 (blp or CG1409) stimulates Hsp70 ATP hydrolysis, and the nucleotide exchange factor Roe1 (GrpE) recycles Hsp70.
Annotons
CG11779 Presequence translocase-associated motor
pam_motor_cg11779
Participant: Gene Product: CG11779
Gene Product:
CG11779UniProtKB:Q9VDZ7
Processes
protein import into mitochondrial matrixGO:0030150
CG1409 Presequence translocase-associated motor
pam_motor_cg1409
Participant: Gene Product: CG1409
Gene Product:
CG1409UniProtKB:Q9W3P5
Processes
protein import into mitochondrial matrixGO:0030150
CG7394 Presequence translocase-associated motor
pam_motor_cg7394
Participant: Gene Product: CG7394
Gene Product:
CG7394UniProtKB:Q9VTJ8
Processes
protein import into mitochondrial matrixGO:0030150
Hsc70-5 Presequence translocase-associated motor
pam_motor_hsc70_5
Participant: Gene Product: Hsc70-5
Gene Product:
Hsc70-5UniProtKB:P29845
Function
ATP-dependent protein folding chaperoneGO:0140662
Processes
protein import into mitochondrial matrixGO:0030150
Roe1 Presequence translocase-associated motor
pam_motor_roe1
Participant: Gene Product: Roe1
Gene Product:
Roe1UniProtKB:P48604
Function
adenyl-nucleotide exchange factor activityGO:0000774
Processes
protein import into mitochondrial matrixGO:0030150
blp Presequence translocase-associated motor
pam_motor_blp
Participant: Gene Product: blp
Gene Product:
Processes
protein import into mitochondrial matrixGO:0030150
Part 6: oxidative import into the intermembrane space
Mitochondrial disulfide relayBiological Processdisulfide_relay
Mia40 traps incoming cysteine-rich precursors by disulfide exchange and is reoxidised by the sulfhydryl oxidase Alr; in mammals the AIF ortholog AIFM1 is needed for normal Mia40 (CHCHD4) import and levels.
Annotons
AIF Mitochondrial disulfide relay
disulfide_relay_aif
Participant: Gene Product: AIF
Gene Product:
Processes
protein import into mitochondrial intermembrane spaceGO:0045041
Alr Mitochondrial disulfide relay
disulfide_relay_alr
Participant: Gene Product: Alr
Gene Product:
Function
thiol oxidase activityGO:0016972
Processes
protein import into mitochondrial intermembrane spaceGO:0045041
Mia40 Mitochondrial disulfide relay
disulfide_relay_mia40
Participant: Gene Product: Mia40
Gene Product:
Mia40UniProtKB:Q9VAA6
Processes
protein import into mitochondrial intermembrane spaceGO:0045041
Part 7: presequence cleavage in the matrix
Mitochondrial processing peptidaseBiological Processmpp
Heterodimer of Mppa (alpha) and UQCR-C1 (beta) that removes matrix-targeting presequences.
Annotons
Mitochondrial processing peptidase
mpp_complex
Participant: Protein Complex: Mitochondrial processing peptidase
Protein Complex:
Function
metalloendopeptidase activityGO:0004222
Part 8: second-step cleavage of intermembrane space-sorted precursors
Inner membrane peptidaseBiological Processimp
Annotons
Inner membrane peptidase
imp_complex
Participant: Protein Complex: Inner membrane peptidase
Protein Complex: