GO:0140917 zinc ion import into mitochondrion: Mitochondrial Zinc Homeostasis, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140917 describes the directed import of zinc(2+) from the cytosol across an organelle membrane into a mitochondrion.
• Mitochondrial zinc import is essential for the maturation and function of mitochondrial intermembrane space proteins, including small Tim chaperones and the import receptor Mia40.
• Zinc can act as a chaperone-like factor during import of mitochondrial small Tim proteins, but excess zinc inhibits the process.
• Kinetic studies in prostate cells identified a mitochondrial zinc uptake transport process, linking zinc import to prostate cancer biology.
• Fluorescent sensors enable real-time measurement of mobile Zn2+ in mitochondria of healthy versus cancerous prostate cells.
• Dysregulated mitochondrial zinc import is implicated in cancer, neurodegeneration, and mitochondrial dysfunction, making it a target for CRISPR-based functional studies.
Description
Zinc is an essential trace element that serves as a structural cofactor and signaling ion in cells. While the cytosolic and vesicular roles of zinc are well studied, the mechanisms and functions of zinc within mitochondria are only beginning to be understood. GO:0140917, zinc ion import into mitochondrion, defines the directed import of zinc(2+) from the cytosol across an organelle membrane into a mitochondrion. This process is distinct from general metal ion transport because it specifically delivers zinc to the mitochondrial matrix and intermembrane space, where it supports protein folding, oxidative folding, and metalation of mitochondrial proteins. Research over the past two decades has revealed that mitochondrial zinc import is tightly coupled to the import and maturation of nuclear-encoded mitochondrial proteins. For example, zinc-dependent intermembrane space proteins stimulate the import of carrier proteins into plant mitochondria, and small Tim proteins require zinc for their import and function. The zinc-binding protein Hot13 promotes oxidation of the mitochondrial import receptor Mia40, highlighting a direct role for zinc in the mitochondrial disulfide relay system. Dysregulation of mitochondrial zinc homeostasis has been linked to human disease, particularly cancer. Kinetic identification of a mitochondrial zinc uptake transport process in prostate cells and the development of reaction-based fluorescent sensors for mobile Zn2+ in mitochondria of healthy versus cancerous prostate cells have provided tools to study this process in disease contexts. Understanding GO:0140917 is therefore critical for researchers investigating mitochondrial biology, metal homeostasis, and cancer metabolism.
zinc ion import into mitochondrion At A Glance
| GO ID | GO:0140917 |
|---|---|
| GO term | zinc ion import into mitochondrion |
| Ontology | biological_process |
| Synonym | none |
| Major function | Directed import of zinc(2+) from the cytosol across an organelle membrane into a mitochondrion |
| Related ions | Zinc(2+), mobile Zn2+ |
| Subcellular location | Mitochondrion, mitochondrial intermembrane space, mitochondrial matrix |
| Associated proteins | Small Tim proteins, Mia40, Hot13, mitochondrial carrier proteins |
| Research tools | Fluorescent zinc sensors, kinetic uptake assays, CRISPR models |
What Is GO:0140917?
GO:0140917, zinc ion import into mitochondrion, is a biological process defined as the directed import of zinc(2+) from the cytosol, across an organelle membrane, into a mitochondrion. This term encompasses the transport steps that move zinc ions from the cytoplasmic compartment into the mitochondrial matrix or intermembrane space, and it is distinct from zinc export, zinc storage, or zinc-dependent enzymatic reactions that occur after import.
Why Is zinc ion import into mitochondrion Important in Cell Biology?
Mitochondrial zinc import is essential for mitochondrial biogenesis and function because zinc is required for the folding, stability, and activity of numerous mitochondrial proteins. Zinc-dependent intermembrane space proteins stimulate the import of carrier proteins into plant mitochondria, and small Tim proteins require zinc for their import into the intermembrane space. The zinc-binding protein Hot13 promotes oxidation of the mitochondrial import receptor Mia40, which is a key step in the mitochondrial disulfide relay. In prostate cells, a mitochondrial zinc uptake transport process has been kinetically identified, and mobile Zn2+ levels in mitochondria differ between healthy and cancerous prostate cells. These findings link GO:0140917 to cancer biology, metal homeostasis, and mitochondrial dysfunction.
• Supports the import and maturation of mitochondrial intermembrane space proteins, including small Tim chaperones.
• Enables the oxidative folding of Mia40 substrates through the zinc-binding protein Hot13.
• Stimulates carrier protein import into mitochondria, as shown in plant mitochondria.
• Provides a mechanism for mitochondrial zinc uptake that can be kinetically distinguished from other transport processes.
• Is altered in cancerous prostate cells, where mitochondrial mobile Zn2+ levels differ from healthy cells.
• Can be studied with reaction-based fluorescent sensors that report mobile Zn2+ in mitochondria.
• Is relevant to neurodegeneration and mitochondrial dysfunction, where zinc homeostasis is disrupted.
• Offers a target for CRISPR knockout, knock-in, and overexpression studies of mitochondrial zinc transporters.
• Connects metal homeostasis to mitochondrial protein import and oxidative folding pathways.
• Has implications for cancer metabolism and the development of zinc-targeted therapies.
What Happens During zinc ion import into mitochondrion?
Recognition and transport of zinc across the mitochondrial membrane
In simple terms: Zinc ions are recognized and moved from the cytosol into the mitochondrion.
The process begins with the directed import of zinc(2+) from the cytosol across an organelle membrane into a mitochondrion. Kinetic studies in prostate cells have identified a mitochondrial zinc uptake transport process, suggesting the existence of specific transport machinery that can be distinguished from other zinc fluxes. Reaction-based fluorescent sensors have been used to visualize mobile Zn2+ in mitochondria of healthy versus cancerous prostate cells, confirming that mitochondrial zinc import is a regulated and measurable process.
Zinc-dependent stimulation of carrier protein import
In simple terms: Zinc helps other proteins get into mitochondria.
Zinc-dependent intermembrane space proteins stimulate the import of carrier proteins into plant mitochondria. This indicates that zinc import is functionally coupled to the import of mitochondrial carrier proteins, which are essential for metabolite exchange across the inner membrane. The intermembrane proteins Tim10/Mrs11 and Tim12/Mrs5 mediate carrier protein import into mitochondria, and their function is influenced by zinc availability.
Zinc as a chaperone-like factor for small Tim proteins
In simple terms: Zinc acts like a helper that guides small Tim proteins into mitochondria.
Zinc can play chaperone-like and inhibitor roles during import of mitochondrial small Tim proteins. Small Tim proteins are imported into the mitochondrial intermembrane space, and zinc binding is important for their stability and function. However, excess zinc can inhibit the import process, indicating that zinc levels must be tightly controlled.
Zinc-dependent oxidative folding via Mia40 and Hot13
In simple terms: Zinc helps the mitochondrial import receptor Mia40 do its job.
The zinc-binding protein Hot13 promotes oxidation of the mitochondrial import receptor Mia40. Mia40 is a key component of the mitochondrial disulfide relay system that oxidizes imported intermembrane space proteins. Because Hot13 binds zinc, mitochondrial zinc import is directly linked to the oxidative folding of Mia40 substrates. This connects GO:0140917 to the broader mitochondrial protein import and quality control network.
Key Genes Involved in GO:0140917 zinc ion import into mitochondrion
The following genes and proteins have been experimentally linked to zinc ion import into mitochondrion or to zinc-dependent mitochondrial import processes.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TIMM10 | Small Tim protein mediating carrier protein import into mitochondria | Zinc-dependent import and chaperone-like function |
| TIMM12 | Small Tim protein mediating carrier protein import into mitochondria | Zinc-dependent import and chaperone-like function |
| TIMM9 | Small Tim protein involved in mitochondrial intermembrane space import | Zinc-dependent import and chaperone-like function |
| MIA40 | Mitochondrial import receptor and oxidoreductase | Oxidation promoted by zinc-binding Hot13 |
| HOT13 | Zinc-binding protein that promotes Mia40 oxidation | Direct zinc-binding role in mitochondrial import |
| SLC30A9 | Mitochondrial zinc transporter (ZnT9) | Candidate for mitochondrial zinc export/import balance |
| SLC39A8 | Zinc importer (ZIP8) with mitochondrial localization | Potential role in mitochondrial zinc uptake |
| MT1A | Metallothionein involved in zinc buffering | Zinc homeostasis and mitochondrial zinc availability |
| MT2A | Metallothionein involved in zinc buffering | Zinc homeostasis and mitochondrial zinc availability |
| SOD2 | Manganese-dependent mitochondrial antioxidant enzyme | Zinc-related oxidative stress and mitochondrial function |
| COX4I1 | Cytochrome c oxidase subunit | Zinc-dependent mitochondrial protein import and assembly |
| ATP5F1A | Mitochondrial ATP synthase subunit | Zinc-dependent mitochondrial protein import and assembly |
| VDAC1 | Mitochondrial outer membrane channel | Zinc transport and mitochondrial permeability |
| MCU | Mitochondrial calcium uniporter | Comparative metal ion transport studies |
| ZIP1 (SLC39A1) | Zinc importer | Cellular zinc uptake and mitochondrial zinc pools |
| ZIP2 (SLC39A2) | Zinc importer | Cellular zinc uptake and mitochondrial zinc pools |
| ZIP3 (SLC39A3) | Zinc importer | Cellular zinc uptake and mitochondrial zinc pools |
| ZnT1 (SLC30A1) | Zinc exporter | Cellular zinc efflux and mitochondrial zinc pools |
How Is zinc ion import into mitochondrion Regulated?
Mitochondrial zinc import is regulated by the availability of cytosolic zinc, the expression and activity of mitochondrial zinc transporters, and the redox state of the mitochondrial intermembrane space. Zinc can act as a chaperone-like factor for small Tim proteins, but excess zinc inhibits their import, indicating a narrow optimal concentration range. The zinc-binding protein Hot13 promotes oxidation of Mia40, linking zinc import to the mitochondrial disulfide relay and oxidative folding capacity. In prostate cells, mitochondrial zinc uptake is kinetically distinct and can be measured with fluorescent sensors, suggesting regulation by cell type and metabolic state. Zinc-dependent intermembrane space proteins also stimulate carrier protein import, providing a feedback mechanism between zinc availability and mitochondrial protein import.
zinc ion import into mitochondrion and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TIMM10 | Mitochondrial protein import defects | Knockout and point-mutation cell models |
| MIA40 | Mitochondrial myopathy and oxidative folding defects | Knock-in of patient variants |
| HOT13 | Mitochondrial disulfide relay dysfunction | Overexpression and knockout models |
| SLC30A9 | Zinc homeostasis and mitochondrial dysfunction | Knockout and tagged knock-in models |
| SLC39A8 | Zinc metabolism and cancer | Overexpression and knockout models |
Mitochondrial zinc import in prostate cancer
Kinetic identification of a mitochondrial zinc uptake transport process in prostate cells and the development of reaction-based fluorescent sensors for mobile Zn2+ in mitochondria of healthy versus cancerous prostate cells have linked mitochondrial zinc import to prostate cancer biology. Cancerous prostate cells show altered mitochondrial mobile Zn2+ levels compared to healthy cells, suggesting that dysregulated zinc import contributes to cancer metabolism. These findings make GO:0140917 a candidate pathway for therapeutic targeting in prostate cancer.
Zinc homeostasis and neurodegeneration
Zinc dyshomeostasis is a feature of several neurodegenerative conditions, and mitochondrial dysfunction is a common pathological hallmark. Sensors for measuring subcellular zinc pools have enabled researchers to probe mitochondrial zinc in neurons and other cell types. Because mitochondrial zinc import supports the folding and function of intermembrane space proteins, disruption of this process may contribute to neuronal mitochondrial dysfunction. However, direct evidence linking GO:0140917 to specific neurodegenerative diseases remains an active area of research.
Mitochondrial protein import defects and disease
Defects in mitochondrial protein import are associated with a range of human disorders, including mitochondrial myopathies and cardiomyopathies. Small Tim proteins and Mia40 are essential for the import and oxidative folding of intermembrane space proteins. Zinc-dependent stimulation of carrier protein import and the chaperone-like role of zinc for small Tim proteins indicate that perturbations in mitochondrial zinc import could impair mitochondrial biogenesis. Research using CRISPR models can help determine whether specific zinc import genes are causally involved in these import defects.
From zinc ion import into mitochondrion-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is a candidate gene required for mitochondrial zinc import? | CRISPR knockout cell line |
| Does a specific zinc-binding residue mediate import? | Point-mutation knock-in cell line |
| Where does the protein localize within mitochondria? | Tagged knock-in with fluorescent tag |
| Does overexpression alter mitochondrial zinc levels? | Overexpression cell line |
| Which genes regulate mitochondrial zinc import? | CRISPR library screening |
| What pathways are affected by loss of zinc import? | RNA-seq and proteomics of knockout cells |
How to Study the zinc ion import into mitochondrion Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescent zinc sensors | Mobile Zn2+ levels in mitochondria | Live-cell imaging of healthy vs cancerous cells |
| Kinetic uptake assays | Rate and specificity of mitochondrial zinc uptake | Characterizing transporter activity |
| Protein import assays | Import of small Tim and carrier proteins | Testing zinc dependence of import |
| CRISPR knockout | Loss-of-function effects on zinc import | Identifying essential genes |
| RNA-seq | Transcriptional changes after gene perturbation | Pathway analysis of zinc import mutants |
| Proteomics | Protein abundance and interactions | Identifying zinc-dependent mitochondrial proteins |
| CRISPR library screening | Genome-wide fitness and transport phenotypes | Discovering novel regulators |
| Bioinformatics | Integration of multi-omics data | Network and pathway modeling |
Fluorescent sensors for mitochondrial zinc
Reaction-based fluorescent sensors enable real-time measurement of mobile Zn2+ in mitochondria of living cells. These sensors can distinguish healthy versus cancerous prostate cells and are valuable for studying GO:0140917 in disease contexts. Sensors for measuring subcellular zinc pools provide a broader toolkit for probing mitochondrial zinc dynamics.
Kinetic uptake assays
Kinetic identification of mitochondrial zinc uptake transport processes allows researchers to measure the rate and specificity of zinc import in intact cells or isolated mitochondria. Such assays can distinguish mitochondrial zinc uptake from other cellular zinc fluxes and are useful for characterizing transporter mutants.
Protein import assays
In vitro and in organello protein import assays measure the import of small Tim proteins and carrier proteins into mitochondria. These assays can be combined with zinc chelators or zinc supplementation to test the zinc dependence of import. They are essential for linking GO:0140917 to mitochondrial biogenesis.
CRISPR screening and bioinformatics
CRISPR library screening can identify genes required for mitochondrial zinc import and homeostasis. Bioinformatics analysis of screening data, combined with transcriptomic and proteomic profiling, can reveal pathways and networks connected to GO:0140917. These approaches are particularly useful when the core transport machinery is unknown or redundant.
How CRISPR Can Be Used to Study GO:0140917 zinc ion import into mitochondrion
Knockout
CRISPR knockout cell models can be used to delete candidate genes involved in zinc ion import into mitochondrion, such as TIMM10, TIMM12, MIA40, or HOT13. Loss-of-function phenotypes can be assessed using fluorescent zinc sensors, kinetic uptake assays, and protein import assays. Knockout models help determine whether a gene is essential for mitochondrial zinc homeostasis.
Point Mutation
Point-mutation knock-in models allow researchers to test the functional significance of specific residues, such as zinc-binding cysteines or histidines in small Tim proteins or Hot13. These models are particularly useful for dissecting the chaperone-like versus inhibitory roles of zinc during small Tim protein import. Point mutations can also be introduced into transporter genes to test substrate specificity.
Knock-in
Knock-in models can be used to tag endogenous proteins with fluorescent or affinity tags to study their localization and interactions. For example, tagging Mia40 or Hot13 can reveal their dynamic behavior during mitochondrial zinc import. Knock-in of disease-associated variants can also model human disorders linked to mitochondrial zinc dyshomeostasis.
Overexpression
Overexpression cell models can be used to increase the levels of candidate zinc import proteins and assess their effects on mitochondrial zinc levels and mitochondrial function. Overexpression of zinc-binding proteins such as Hot13 may enhance Mia40 oxidation, while overexpression of transporters may alter mitochondrial zinc pools. These models complement knockout and knock-in approaches.
How EDITGENE Supports zinc ion import into mitochondrion Research
Researchers studying zinc ion import into mitochondrion-related genes often need to determine whether a candidate gene is causally involved in mitochondrial zinc homeostasis, protein import, or disease phenotypes. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, enabling functional validation of genes linked to GO:0140917.
Contact EDITGENE today to design your custom CRISPR model for zinc ion import into mitochondrion research.
Frequently Asked Questions About zinc ion import into mitochondrion
What is zinc ion import into mitochondrion (GO:0140917)?
GO:0140917 is a biological process defined as the directed import of zinc(2+) from the cytosol, across an organelle membrane, into a mitochondrion.
What genes are involved in zinc ion import into mitochondrion?
Genes and proteins linked to this process include small Tim proteins (TIMM9, TIMM10, TIMM12), Mia40, Hot13, and zinc transporters such as SLC30A9 and SLC39A8.
Why is mitochondrial zinc import important?
It supports the import and oxidative folding of mitochondrial intermembrane space proteins, stimulates carrier protein import, and is linked to cancer and mitochondrial dysfunction.
How is mitochondrial zinc import measured?
It can be measured using reaction-based fluorescent sensors for mobile Zn2+, kinetic uptake assays, and in vitro protein import assays.
What is the role of zinc in small Tim protein import?
Zinc can act as a chaperone-like factor for small Tim proteins, but excess zinc inhibits their import, indicating a narrow optimal concentration range.
What is the role of Hot13 in mitochondrial zinc import?
Hot13 is a zinc-binding protein that promotes oxidation of the mitochondrial import receptor Mia40, linking zinc to the mitochondrial disulfide relay.
Is mitochondrial zinc import altered in cancer?
Yes, mitochondrial mobile Zn2+ levels differ between healthy and cancerous prostate cells, and a mitochondrial zinc uptake transport process has been identified in prostate cells.
What research methods are used to study GO:0140917?
Common methods include fluorescent zinc sensors, kinetic uptake assays, protein import assays, CRISPR knockout and knock-in models, RNA-seq, proteomics, and CRISPR library screening.
Can CRISPR be used to study mitochondrial zinc import?
Yes, CRISPR knockout, point-mutation, knock-in, and overexpression models can be used to dissect the function of genes involved in GO:0140917.
What diseases are linked to mitochondrial zinc import?
Prostate cancer and mitochondrial protein import defects are linked to this process, and zinc dyshomeostasis is implicated in neurodegeneration.
Conclusion
GO:0140917, zinc ion import into mitochondrion, is a fundamental biological process that delivers zinc to the mitochondrial compartments where it supports protein import, oxidative folding, and mitochondrial function. Research over the past two decades has identified key proteins, including small Tim chaperones, Mia40, and Hot13, that depend on or regulate zinc during mitochondrial import. Dysregulation of this process has been linked to prostate cancer and mitochondrial dysfunction, making it a compelling target for further study. CRISPR-based cell models, combined with fluorescent zinc sensors and kinetic assays, provide powerful tools to dissect the molecular mechanisms and disease relevance of GO:0140917. EDITGENE offers comprehensive knockout, point-mutation, knock-in, overexpression, library screening, and bioinformatics services to accelerate research on mitochondrial zinc import and its role in human health and disease.
References
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- 2. Lister R et al.. 2002. Zinc-dependent intermembrane space proteins stimulate import of carrier proteins into plant mitochondria.. Plant J 30(5):555-66 PMID: 12047630
- 3. Lutz T et al.. 2003. Import of small Tim proteins into the mitochondrial intermembrane space.. EMBO J 22(17):4400-8 PMID: 12941692
- 4. Guan Z et al.. 2003. Kinetic identification of a mitochondrial zinc uptake transport process in prostate cells.. J Inorg Biochem 97(2):199-206 PMID: 14512198
- 5. Morgan B et al.. 2009. Zinc can play chaperone-like and inhibitor roles during import of mitochondrial small Tim proteins.. J Biol Chem 284(11):6818-25 PMID: 19117943
- 6. Mesecke N et al.. 2008. The zinc-binding protein Hot13 promotes oxidation of the mitochondrial import receptor Mia40.. EMBO Rep 9(11):1107-13 PMID: 18787558
- 7. Sirrenberg C et al.. 1998. Carrier protein import into mitochondria mediated by the intermembrane proteins Tim10/Mrs11 and Tim12/Mrs5.. Nature 391(6670):912-5 PMID: 9495346
- 8. Chyan W et al.. 2014. Reaction-based fluorescent sensor for investigating mobile Zn2+ in mitochondria of healthy versus cancerous prostate cells.. Proc Natl Acad Sci U S A 111(1):143-8 PMID: 24335702
