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TOMM22 / Mitochondrial import receptor subunit TOM22 homolog · IHC design guide
Design Immunohistochemistry for TOMM22
Plan paraffin-section TOMM22 IHC around the granular cytoplasmic tissue pattern (HPA tissue IHC). The catalog antibody was used at 1:100 overnight at 4°C, followed by HRP/DAB detection (datasheet A08668-1).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
TOMM22 Immunohistochemistry Experimental Design Guide
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before staining
| Expected localisation | Granular cytoplasm (HPA tissue IHC); mitochondrial outer membrane (UniProt) | |
| Staining pattern | Ubiquitous granular cytoplasmic staining (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A08668-1) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | None in HPA (detected in all 45 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific) | |
| Caveat | Bone marrow hematopoietic cells stain highly; score by cell type (HPA tissue IHC) | |
| Regulation | No regulator reported (UniProt) | |
| Isoform / epitope | No isoforms listed; epitope side unspecified (UniProt) |
Section 1
Recommended TOMM22 IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet: A08668-1) is followed by published TOMM22 IHC methods for brain sections (PMC8215754) and pancreatic tissue (PMC11673509).
| Sample | Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A08668-1) |
| Fixation | Image fixative and duration unreported (datasheet A08668-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A08668-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A08668-1) |
| Primary antibody | Rabbit anti-TOMM22, 1:50 recommended; image 1:100 (datasheet A08668-1) |
| Primary incubation | Overnight at 4 °C (datasheet A08668-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A08668-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | TOMM22-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Ubiquitous cytoplasmic expression in a granular pattern. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet: A08668-1). Use citrate pH 6 to reproduce the pancreatic protocol (PMC11673509).
Section 2
What Is the Expected TOMM22 Staining Pattern?
TOMM22 resides in the mitochondrial outer membrane, with residues 2–83 facing the cytoplasm and 104–142 facing the intermembrane space (UniProt Q9NS69 topology). In paraffin section IHC, expect granular cytoplasmic staining across many cell types, consistent with the HPA tissue profile and its Supported reliability rating (HPA: ubiquitous granular cytoplasmic expression; IHC Supported).
| Granular cytoplasmic chromogen in glandular, respiratory epithelial, hematopoietic, or glial cells. | This fits the mitochondrial location and reported tissue pattern (UniProt Q9NS69 location; HPA: ubiquitous granular cytoplasmic expression). HPA reports High staining in these cell types in the listed tissues, including adrenal gland, bronchus, bone marrow, and cerebral cortex (HPA: tissue IHC). |
| Predominantly nuclear or cell surface staining, without a convincing granular cytoplasmic component. | The dominant compartment conflicts with the reported mitochondrial location (UniProt Q9NS69 location; HPA: tissue IHC). Treat it as a possible artefact and review morphology, controls, and detection conditions before assigning TOMM22 expression (general IHC practice). |
| Strong signal confined to cells that do not match the expected staining within the sampled tissue. | Check cell identity against the tissue's HPA image and report; unexpected staining can reflect cross-reactivity or endogenous detection activity (HPA: tissue IHC; general IHC practice). Ubiquitous expression means an unlisted cell type alone is not evidence of a false positive (UniProt Q9NS69 tissue specificity). |
| Diffuse color fills tissue spaces or obscures cellular granules. | That appearance is less interpretable than the reported granular cytoplasmic pattern (HPA: tissue IHC). Assess background with appropriate detection controls and review blocking, washing, and chromogen development as general IHC variables (general IHC practice). |
| No signal in a section containing a documented High staining cell population. | A negative result in, for example, adrenal gland glandular cells or bone marrow hematopoietic cells warrants an assay check (HPA: High in adrenal gland glandular cells; High in bone marrow hematopoietic cells). It does not by itself show that TOMM22 is absent (general IHC practice). |
💡Expected TOMM22 appearanceCall a result positive when identifiable cells show granular cytoplasmic chromogen, with strong staining plausible in HPA High populations; dominant nuclear or diffuse tissue wide color is suspect (HPA: tissue IHC; UniProt Q9NS69 location).
| Membrane topology | TOMM22 spans the mitochondrial outer membrane at residues 84–103 (UniProt Q9NS69 topology). The antibody epitope is not supplied, so topology alone cannot predict whether a particular retrieval condition will expose it (UniProt Q9NS69 topology; supplied evidence). |
| Tissue distribution | TOMM22 is described as ubiquitous, while HPA reports low RNA tissue specificity and ubiquitous granular cytoplasmic IHC (UniProt Q9NS69 tissue specificity; HPA: tissue IHC). Compare compartments and cell identity before treating intensity differences as expression differences (general IHC practice). |
| Reference staining | HPA reports High staining in adrenal gland and appendix glandular cells, bronchus respiratory epithelial cells, and caudate glial cells (HPA: tissue IHC). These are observed examples, not prescribed positive controls for every run (HPA: tissue IHC). |
| Strength of IHC evidence | The tissue IHC profile is Supported because antibody staining is consistent with RNA data (HPA: tissue IHC reliability). HPA003037 is IHC Supported; HPA074642 has no stated IHC status in the supplied antibody record (HPA: antibodies). |
| IF/ICC Q: Where should signal appear? | A: In mitochondria (HPA: ICC-IF, mitochondria Enhanced; UniProt Q9NS69 location). This localization supports interpretation of the IHC pattern; IF/ICC assay design belongs in its separate guide (HPA: subcellular ICC-IF). |
| Situation | Likely cause | Next action |
|---|---|---|
| No chromogen in a known High staining cell population. | An assay or detection failure is possible; absence cannot be assigned from one negative section (HPA: tissue IHC; general IHC practice). | Check a documented High staining population, section integrity, primary antibody use, and detection controls; review the catalog antibody's IHC-P instructions for its specified conditions (HPA: tissue IHC; general IHC practice). |
| Weak granules are difficult to distinguish from background. | Low contrast can obscure the reported granular cytoplasmic pattern (HPA: tissue IHC; general IHC practice). | Compare stained cells with a detection control and inspect at higher magnification; adjust general IHC detection conditions only against controls (general IHC practice). |
| Nuclei carry the dominant signal. | A dominant nuclear pattern conflicts with mitochondrial TOMM22 localization (UniProt Q9NS69 location; HPA: ICC-IF mitochondria). | Verify the counterstain and chromogen separately, then inspect controls and repeat interpretation by compartment rather than counting all dark cells as positive (general IHC practice). |
| Only an unexpected cell population stains strongly. | Cell identification may be wrong, or cross-reactivity or endogenous detection activity may contribute (general IHC practice). | Confirm morphology and compare the same tissue with HPA staining; use appropriate detection controls. Do not label unlisted cells negative solely because TOMM22 is widespread (HPA: tissue IHC; UniProt Q9NS69 tissue specificity; general IHC practice). |
| Broad, smooth color replaces discrete cytoplasmic granules. | Diffuse background can mask the HPA reported granular pattern (HPA: tissue IHC; general IHC practice). | Review blocking, washes, and chromogen development with a detection control; score cellular granules only when they remain distinguishable from background (general IHC practice). |
| A proposed negative tissue control stains. | No negative tissue is supplied, and TOMM22 is described as ubiquitous (HPA: tissue IHC negative list empty; UniProt Q9NS69 tissue specificity). | Use a detection control to assess nonspecific color and compare compartment patterns in documented HPA tissues; do not treat an unlisted tissue as a validated negative (HPA: tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing TOMM22 staining
A08668-1 · IHCIHC analysis of TOM22/TOMM22 using anti-TOM22/TOMM22 antibody (A08668-1). TOM22/TOMM22 was detected in a paraffin-embedded section of human
A08668-1 · IHCIHC analysis of TOM22/TOMM22 using anti-TOM22/TOMM22 antibody (A08668-1). TOM22/TOMM22 was detected in a paraffin-embedded section of human
M08668 · IFImmunofluorescent analysis using the Antibody at 1:50 dilution.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000100216-TOMM22/tissue/cerebral+cortex#imid_2192352
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000100216-TOMM22/tissue/colon#imid_2192278
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000100216-TOMM22/tissue/liver#imid_2192295
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000100216-TOMM22/tissue/kidney#imid_2192280
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA003037; green = TOMM22, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA003037; green = TOMM22, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for TOMM22 IHC & IF
🧪Run bone marrow first and expect staining in hematopoietic cells (HPA: High in bone marrow hematopoietic cells). HPA detects TOMM22 in all 45 scored tissues, so there is no supported negative tissue; use no-primary and isotype controls, and expect mature erythrocytes within the section to lack mitochondrial staining (HPA: no negative tissue rows; standard cell biology: mature erythrocytes lack mitochondria; UniProt Q9NS69: mitochondrial outer membrane).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: None in HPA: TOMM22 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show TOMM22 in A-431, U-251MG, U2OS, HEK293, U2OS, siRNA 1 (10x), U2OS, siRNA 1 (40x), U2OS, siRNA 2 (10x), U2OS, siRNA 2 (40x), U2OS, scrambled (10x), U2OS, scrambled (40x), with annotated localisation: Mitochondria (enhanced) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only slide, a host- and clonality-matched rabbit IgG control, and a TOMM22 knockout sample or validated peptide-block control (selected-SKU caption: rabbit primary; standard IHC control practice). Quench endogenous peroxidase before DAB detection because marrow myeloid cells can contribute peroxidase signal (HPA: bone marrow positive tissue; standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported, and the selected A08668-1 tissue-IHC caption does not state its fixative (selected-SKU caption: fixative unreported). The paraffin-section example uses heat retrieval in EDTA at pH 8.0, which provides a starting condition but does not establish that retrieval is required (selected-SKU caption: EDTA heat retrieval). Frozen-section performance is unreported; IF/ICC may make mitochondrial localization easier to assess, while endogenous peroxidase in bone marrow can complicate chromogenic scoring (HPA: mitochondrial ICC-IF localization and bone marrow positive tissue; standard IHC practice).
HPA tissue IHC evidence for TOMM22
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — High consistency between antibody staining and RNA expression data.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: TOMM22 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced TOMM22 IHC Tips
TOMM22 IHC should show granular cytoplasmic staining consistent with its mitochondrial outer membrane location (HPA: tissue IHC profile; UniProt Q9NS69 localization).
Which retrieval condition should I start with for TOMM22 paraffin-section IHC?
Start with heat-mediated EDTA pH 8.0 retrieval for TOMM22 paraffin-section IHC (datasheet A08668-1). The selected tissue image used this condition before 10% goat-serum blocking and 1:100 primary antibody overnight at 4°C (datasheet A08668-1). Compare retrieved and no-retrieval sections for granular cytoplasmic signal while keeping antibody concentration and detection constant (HPA: ubiquitous granular cytoplasmic expression; standard IHC practice). If staining remains weak, adjust heating duration or test a citrate-buffer fallback on adjacent sections, selecting the condition that preserves morphology and limits diffuse DAB (standard IHC practice).
How should I investigate fixation as a cause of weak TOMM22 staining?
The selected paraffin-section image does not report its fixative, so TOMM22-specific fixation sensitivity is unknown (datasheet A08668-1: fixative unreported). Record the fixative and fixation duration for each specimen, then compare matched sections before attributing weak staining to antigen retrieval or antibody concentration (standard IHC practice). Keep section thickness, EDTA pH 8.0 retrieval, and chromogenic detection constant during that comparison (datasheet A08668-1: retrieval; standard IHC practice). Judge staining alongside tissue morphology and the expected granular cytoplasmic pattern; weak DAB alone does not establish low TOMM22 abundance (HPA: tissue IHC profile; standard IHC practice).
What TOMM22 staining pattern should count as correctly localised in IHC?
Look for cytoplasmic granules in viable cells, consistent with TOMM22 on the mitochondrial outer membrane (HPA: ubiquitous granular cytoplasmic expression; UniProt Q9NS69 localization). TOMM22 has a transmembrane segment at residues 84–103, with residues 2–83 cytoplasmic and 104–142 facing the intermembrane space (UniProt Q9NS69 topology). Score intracellular granularity separately from uniform cytoplasmic haze, nuclear staining, and extracellular deposits, which do not match the expected compartment (HPA: tissue IHC profile; standard IHC practice). Interpret intensity within the same cell type and processing batch because mitochondrial distribution and section quality affect how readily granules can be resolved (standard IHC practice).
Could epitope location explain inconsistent TOMM22 IHC staining?
The antibody epitope is not specified in the selected tissue caption, so do not assign poor staining to a particular side of TOMM22 (datasheet A08668-1: epitope unreported). Its cytoplasmic region spans residues 2–83, its membrane segment 84–103, and its intermembrane region 104–142 (UniProt Q9NS69 topology). UniProt lists 0 annotated isoforms and reports phosphorylation at residues 15, 43, and 45; neither annotation establishes an effect on this antibody (UniProt Q9NS69 record). If epitope-dependent masking is suspected, compare retrieval conditions and an independently validated antibody with a documented epitope on matched sections (standard IHC practice).
How can IF help check a TOMM22 chromogenic IHC pattern?
Use IF as a separate localization check for the granular cytoplasmic pattern seen in tissue IHC (HPA: tissue IHC profile; HPA: mitochondria enhanced in ICC/IF). In bronchial sections, multiplex TOMM22 with a respiratory epithelial cell marker to identify the cell population reported as high for TOMM22 (HPA: bronchus respiratory epithelial cells, High; standard IF practice). Choose fluorophores after inspecting unstained tissue autofluorescence and include single-channel controls to assess bleed-through (standard IF practice). Because the antibody epitope is unspecified, compare permeabilization conditions with its membrane topology in mind: residues 2–83 face the cytoplasm and 104–142 face the intermembrane space (datasheet A08668-1: epitope unreported; UniProt Q9NS69 topology; standard IF practice).
How do I reduce diffuse DAB background in TOMM22 IHC?
First compare a no-primary control with the stained section to separate detection-system background from antibody-dependent signal (standard IHC practice). Block endogenous peroxidase before HRP detection, and inspect whether DAB accumulates at section edges or damaged areas (standard IHC practice). The selected caption used 10% goat serum, 1:100 primary antibody overnight at 4°C, and HRP/DAB detection; these are reference conditions for A08668-1 (datasheet A08668-1). If background persists, optimize blocking, antibody concentration, washing, and DAB development one variable at a time while preserving interpretable cytoplasmic granules (standard IHC practice; HPA: tissue IHC profile).
How should I quantify TOMM22 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and viable tissue area before scoring, then apply one threshold and imaging setup across the comparison (standard IHC practice). An H-score combines the percentage of cells at each 0–3 intensity grade into a 0–300 score; report percentage positive alongside it (standard IHC practice). For spatial analyses, report positive-cell density per mm² of viable tissue and normalize comparisons to the sampled viable area or counted cells (standard IHC practice). Record granular cytoplasmic staining separately from diffuse background, and compare like cell types because TOMM22 expression is widespread (HPA: ubiquitous granular cytoplasmic expression; UniProt Q9NS69: ubiquitous tissue specificity; standard IHC practice).
How can I distinguish true TOMM22 staining from artefact?
A convincing positive pattern is granular and cytoplasmic in intact cells, matching the reported tissue staining and mitochondrial localization (HPA: tissue IHC profile; UniProt Q9NS69 localization). Check whether signal is confined to nuclei, extracellular debris, section edges, or necrotic areas; those patterns warrant artefact review (HPA: tissue IHC profile; standard IHC practice). Compare the no-primary control and peroxidase-blocked workflow to investigate endogenous enzyme signal under HRP/DAB detection (datasheet A08668-1: HRP/DAB detection; standard IHC practice). Because TOMM22 is ubiquitous, staining in an unexpected cell population needs cell identification and matched controls rather than an assumption that the population must be negative (UniProt Q9NS69: ubiquitous tissue specificity; standard IHC practice).
Boster reagents
Best TOMM22 / Mitochondrial import receptor subunit TOM22 homolog IHC Antibodies
Anti-TOMM22 options include human paraffin-section IHC images for A08668-1 (A08668-1 IHC captions) and an IF image for M08668 with no sample identified (M08668 IF caption).
Real IHC data
Anti-TOM22/TOMM22 antibody
Cat # A08668-1
Real IF data
Anti-TOMM22/TOM22 Rabbit Monoclonal Antibody
Cat # M08668
A08668-1 will render with human lung cancer paraffin-section IHC (A08668-1 IHC caption); its catalog lists IHC and IF use and Human, Mouse, and Rat reactivity (A08668-1 catalog applications/reactivity). M08668 will render with an IF image at 1:50, with no sample identified (M08668 IF caption); its catalog lists IHC and ICC/IF use and Human reactivity (M08668 catalog applications/reactivity).
Which to pick: For tissue IHC, choose A08668-1: its own captions show human lung and thyroid cancer paraffin sections with EDTA retrieval at pH 8.0 and DAB detection; the fixative is unreported (A08668-1 IHC captions). For IF/ICC, M08668 is the rabbit monoclonal option with an IF image and listed ICC/IF use (M08668 catalog clone/applications; M08668 IF caption). For cross-species work, choose rabbit polyclonal A08668-1, whose listed reactivity includes Human, Mouse, and Rat; M08668 lists Human only (catalog clonality/reactivity).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9NS69 (TOM22_HUMAN, Mitochondrial import receptor subunit TOM22 homolog).
- Human Protein Atlas. TOMM22 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. TOMM22 subcellular location (ICC-IF): Localized to the mitochondria..
- Human Protein Atlas. TOMM22 antibody validation summary (2 antibodies).
- Machine learning and single-cell analysis identify the mitophagy-associated gene TOMM22 as a potential diagnostic biomarker for intervertebral disc degeneration. Heliyon 2024 — PMC11407931.
- Chronic treatment with fluoxetine regulates mitochondrial features and plasticity-associated transcriptomic pathways in parvalbumin-positive interneurons of prefrontal cortex. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 2025 — PMC12518560.
- Identification of sixteen novel candidate genes for late onset Parkinson's disease. Molecular neurodegeneration 2021 — PMC8215754.
- Mitochondrial Translocase TOMM22 Is Overexpressed in Pancreatic Cancer and Promotes Aggressive Growth by Modulating Mitochondrial Protein Import and Function. Molecular cancer research : MCR 2024 — PMC11673509.
- PubMed PMID:10982837 — UniProt-cited evidence.
- PubMed PMID:10900208 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for TOMM22 (Mitochondrial import receptor subunit TOM22 homolog). Expected localisation Granular cytoplasm (HPA tissue IHC); mitochondrial outer membrane (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A08668-1). Validated IHC antibody: A08668-1 at 1:50 recommended; image 1:100 (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative None in HPA (detected in all 45 tissues); use no-primary + isotype controls. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A08668-1); 2. Fixation: Image fixative and duration unreported (datasheet A08668-1); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: EDTA pH 8.0 (datasheet A08668-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A08668-1); 8. Primary antibody: Rabbit anti-TOMM22, 1:50 recommended; image 1:100 (datasheet A08668-1); 9. Primary incubation: Overnight at 4 °C (datasheet A08668-1). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Bone marrow hematopoietic cells stain highly; score by cell type (HPA tissue IHC); Isoform / epitope: No isoforms listed; epitope side unspecified (UniProt); Regulation: No regulator reported (UniProt). Evidence: UniProt Q9NS69, HPA tissue IHC · Supported, HPA ICC-IF · mitochondria., Datasheet A08668-1, PMC8215754, PMC11673509. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/TOMM22/immunohistochemistry-ihc-guide.