| Topic | Key finding | Evidence type | Representative source with year + DOI URL |
|---|---|---|---|
| Localization | Yeast Tim10 is a small Tim family protein located primarily in the mitochondrial intermembrane space (IMS), where it behaves as a soluble chaperone component of the carrier import pathway rather than a matrix or outer-membrane factor. In classic pathway models, a fraction also associates functionally with the TIM22 insertion machinery at the inner membrane interface. (pqac-00000000, pqac-00000025) | Subcellular fractionation, BN-PAGE, review synthesis | Truscott et al., 2002 — https://doi.org/10.1128/mcb.22.22.7780-7789.2002 |
| Complex / stoichiometry | Tim10 assembles with Tim9 into the essential hexameric Tim9–Tim10 chaperone complex; structural work supports a 3:3 alternating arrangement forming a six-bladed assembly with a central channel. A TIM22-associated handoff complex containing Tim9, Tim10, and Tim12 is described as 3:2:1 in pathway models. (pqac-00000001, pqac-00000007, pqac-00000024, pqac-00000030) | X-ray structure, mutagenesis, review | Baker et al., 2009 — https://doi.org/10.1091/mbc.e08-09-0903 |
| Substrates | Tim10 helps chaperone hydrophobic inner-membrane carrier precursors across the aqueous IMS, with strong experimental support for the ADP/ATP carrier (AAC/ANT) as a physiological substrate. More recent pathway work also supports chaperoning of non-canonical TIM22 cargo such as yeast mitochondrial pyruvate carrier proteins. (pqac-00000003, pqac-00000004) | Overlay binding assay, import assay, crosslinking | Vial et al., 2002 — https://doi.org/10.1074/jbc.m202310200 |
| Mechanism step in TIM22 pathway | Tim10 functions after passage of carrier precursors through TOM, binding hydrophobic segments and promoting their release from TOM/GIP intermediates before handoff to the TIM22 insertion complex. In tim10 mutants, AAC accumulates in a high-molecular-mass TOM/GIP-associated intermediate, showing Tim10 acts at the transfer step rather than general mitochondrial import. (pqac-00000000, pqac-00000003, pqac-00000032) | Radiolabeled import assays, protease protection, BN-PAGE, crosslinking | Truscott et al., 2002 — https://doi.org/10.1128/mcb.22.22.7780-7789.2002 |
| IMS targeting / import | Tim10 itself is imported into the IMS via the MIA pathway. Small Tim proteins are synthesized in a reduced, unfolded state, pass through TOM, and are captured by Mia40 through an internal IMS-targeting/sorting signal and cysteine-dependent disulfide exchange, after which Erv1/ALR reoxidizes Mia40. (pqac-00000014, pqac-00000016, pqac-00000018, pqac-00000021) | Import pathway biochemistry, targeting signal mapping, review | Milenkovic et al., 2009 — https://doi.org/10.1091/mbc.e08-11-1108 |
| Redox / disulfides | Tim10 contains the characteristic small-Tim cysteine motif architecture and requires oxidative folding in the IMS. Intramolecular disulfides are crucial for assembly of the mature hexamer; loss of both disulfide bonds is lethal, while selective bond disruption impairs AAC import and chaperone function. (pqac-00000002, pqac-00000029) | Redox-state analysis, cysteine mutagenesis, viability and import assays | Lu et al., 2004 — https://doi.org/10.1074/jbc.m313045200 |
| Biophysical assembly data | Recombinant Tim9 and Tim10 interact tightly and reconstitute a native-like functional chaperone complex of about 60–70 kDa. Vial et al. reported direct Tim9–Tim10 binding with high affinity and showed reconstituted complex binding to AAC and chaperone-like behavior in luciferase refolding assays. (pqac-00000004, pqac-00000031) | ITC, gel filtration/MALS, sedimentation, binding and refolding assays | Vial et al., 2002 — https://doi.org/10.1074/jbc.m202310200 |
| Phenotypes / essentiality | TIM10 is functionally essential for efficient carrier biogenesis: tim10-2 causes roughly a 10-fold reduction in AAC import rate and about a 5-fold reduction in yield after 20 min, while presequence-pathway import remains largely normal. Mutants disrupting complex integrity or disulfide architecture cause temperature-sensitive growth or nonviability, indicating Tim10 is essential at the cellular level. (pqac-00000005, pqac-00000029, pqac-00000032) | Mutant phenotyping, BN-PAGE import assays, growth assays | Truscott et al., 2002 — https://doi.org/10.1128/mcb.22.22.7780-7789.2002 |
| Structural determinants | The Tim9–Tim10 hexamer has mobile N- and C-terminal “tentacles” that help engage hydrophobic precursor segments, while conserved charged residues stabilize the core assembly. Mutation of Tim10 Lys68 destabilizes the soluble hexamer and impairs carrier import without abolishing all TIM22 association. (pqac-00000005, pqac-00000023, pqac-00000030) | Crystal structure, site-directed mutagenesis, import assays | Baker et al., 2009 — https://doi.org/10.1091/mbc.e08-09-0903 |
| Recent 2024 updates | Recent reviews reaffirm Tim10 as a central IMS chaperone of the TIM22 route and place small Tim complexes at the carrier handoff step to TIM22. 2024 work further links small-Tim proteostasis to Yme1 quality control and reports structural/crosslinking evidence for docking of Tim9/Tim10-family chaperones at IMS-facing regions of TIM22-pathway components, refining how precursors may be presented for insertion. (pqac-00000008, pqac-00000009, pqac-00000022, pqac-00000027) | 2024 review synthesis, crosslinking/structural analysis | Kizmaz et al., 2024 — https://doi.org/10.1002/2211-5463.13806 |


*Table: This table summarizes experimentally supported facts about Saccharomyces cerevisiae Tim10 and its role in the TIM22 carrier import pathway. It highlights localization, complex organization, substrate handling, IMS targeting, redox dependence, phenotypes, and recent 2024 pathway-level updates with citation-backed representative sources.*