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TARS2 / Threonine--tRNA ligase, mitochondrial · IHC design guide
Design Immunohistochemistry for TARS2
Plan TARS2 paraffin-section IHC using the reported cytoplasmic and nuclear tissue pattern (HPA tissue IHC). The guide covers positive tissues, antibody concentration and chromogenic detection using the IHC-validated antibody (HPA tissue IHC; datasheet A12437).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
TARS2 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 | Cytoplasmic/nuclear staining (HPA tissue IHC); mitochondrial matrix protein (UniProt) | |
| Staining pattern | Widespread cytoplasmic/nuclear staining; high in glandular cells (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A12437) | |
| Positive control | Gallbladder+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 paraffin-section fixation consistent (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A12437) | |
| Caveat | Staining has medium consistency with RNA expression (HPA tissue IHC) | |
| Regulation | No expression regulator reported (UniProt) | |
| Isoform / epitope | 2 isoforms; epitope effects are unresolved (UniProt) |
Section 1
Recommended TARS2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol uses EDTA retrieval (datasheet A12437). The published TARS2 IHC protocol below uses citrate retrieval (PMC8974053).
| Sample | Paraffin-embedded human colonic adenocarcinoma tissue; fixative not specified (datasheet A12437) |
| Fixation | Image fixative and duration unreported (datasheet A12437); 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 A12437); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A12437) |
| Primary antibody | Rabbit anti-TARS2, 2-5 μg/ml (datasheet A12437) |
| Primary incubation | Overnight at 4 °C (datasheet A12437) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A12437) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | TARS2-positive staining in glandular cells of gallbladder (HPA tissue IHC: High). HPA tissue profile: Ubiquitous cytoplasmic and nuclear expression. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 HIER for the catalog antibody (datasheet A12437); consider citrate pH 6.0 as a published alternative (PMC8974053).
Section 2
What Is the Expected TARS2 Staining Pattern?
TARS2 is annotated in the mitochondrial matrix and has no transmembrane segment (UniProt Q9BW92). In tissue IHC, expect staining in cytoplasm, with possible nuclear staining across many cell types (HPA: ubiquitous cytoplasmic and nuclear expression). Glandular cells and kidney tubule cells provide stronger examples (HPA: High). HPA rates the tissue pattern Approved, with medium agreement between staining and RNA data and external verification pending (HPA: reliability).
| Strong cytoplasmic staining in gallbladder or thyroid glandular cells, or kidney tubule cells (HPA: High). | This matches reported tissue IHC; assess staining within the named cells against nearby tissue and controls (HPA: High; general IHC practice). HPA approval is provisional evidence of pattern, not proof that every stained structure contains TARS2 (HPA: reliability). |
| Cytoplasmic staining with some nuclear signal across several tissues (HPA: tissue IHC profile). | Both compartments occur in the HPA tissue profile, although UniProt places TARS2 in the mitochondrial matrix (HPA: tissue IHC; UniProt Q9BW92). Interpret nuclear signal cautiously rather than rejecting it solely on topology. |
| Predominantly membranous or extracellular chromogen, without a plausible cellular pattern (UniProt Q9BW92 topology). | A membrane-enriched pattern conflicts with TARS2 lacking a transmembrane segment (UniProt Q9BW92). Review morphology, control sections and detection background before assigning such signal to TARS2 (general IHC practice). |
| Apparent strong staining restricted to smooth muscle cells (HPA: Low in smooth muscle). | This exceeds the reported low smooth muscle staining and warrants a specificity check (HPA: Low). Compare an expected high-staining cell population and a negative reagent control; cross-reactivity or endogenous detection activity may explain the discrepancy (general IHC practice). |
| Widespread, structureless color or no visible signal in a high-staining reference tissue (HPA: High tissue examples). | Diffuse color limits cellular scoring; absent signal in an HPA high-staining tissue calls for a run check before biological interpretation (general IHC practice; HPA: High). Neither observation alone establishes a true change in TARS2 expression. |
💡Expected TARS2 appearanceCall a section positive when glandular or kidney tubule cells show clear cytoplasmic staining, potentially with nuclear signal (HPA: High; HPA: tissue IHC profile); isolated membrane or extracellular color is suspect given the matrix annotation and absent transmembrane segment (UniProt Q9BW92).
| Compartment evidence (UniProt Q9BW92; HPA: tissue IHC profile). | UniProt assigns TARS2 to the mitochondrial matrix, while HPA reports cytoplasmic and nuclear tissue staining. Record both observations; the supplied evidence does not resolve whether nuclear IHC represents TARS2. |
| Tissue and cell choice (HPA: High; HPA: Low). | Gallbladder, rectum, small intestine and thyroid glandular cells, plus kidney tubule cells, are reported High; smooth muscle cells are Low. Low is a weaker comparator, not a validated negative control (HPA: tissue IHC). |
| Antibody evidence (HPA: HPA028626 IHC Approved; HPA: reliability). | One listed antibody, HPA028626, has IHC Approved status. The tissue profile has medium staining–RNA agreement and awaits external verification; the supplied record does not claim Enhanced validation (HPA: antibody status; HPA: reliability). |
| Isoforms and processing (UniProt Q9BW92). | UniProt lists two isoforms and a mitochondrial transit peptide keyword, but supplies no section-specific epitope or isoform staining data. These annotations cannot predict which isoform the IHC-validated antibody detects (UniProt Q9BW92). |
| IF/ICC Q&A: What compartment is reported (HPA: subcellular ICC-IF)? | HPA reports nucleoplasm and cytosol, both uncertain, in ICC-IF; UniProt annotates the mitochondrial matrix. Use the separate IF/ICC guide for its workflow, and avoid treating uncertain ICC-IF localization as IHC confirmation (HPA: subcellular ICC-IF; UniProt Q9BW92). |
| Situation | Likely cause | Next action |
|---|---|---|
| No signal in kidney tubules or high-staining glandular cells (HPA: High). | A failed IHC run or insufficient detection is possible; tissue identity and cell preservation also affect interpretation (general IHC practice). | Check a reference section, primary-antibody inclusion and detection reagents; review antigen retrieval against the catalog antibody's IHC-P instructions (general IHC practice). |
| Heavy color covers tissue architecture (general IHC practice). | Excess detection signal, incomplete blocking or endogenous enzyme activity can obscure cellular staining (general IHC practice). | Inspect a no-primary control; adjust blocking, primary dilution or chromogen development using the IHC-P protocol as the starting point (general IHC practice). |
| Strong smooth muscle signal dominates the section (HPA: Low). | The result differs from HPA's low smooth muscle staining; cross-reactivity or background is possible (HPA: Low; general IHC practice). | Compare high-staining cells in the same run and review a no-primary control before scoring smooth muscle as TARS2-positive (HPA: High; general IHC practice). |
| Signal is chiefly membranous or extracellular (UniProt Q9BW92 topology). | That distribution is difficult to reconcile with a matrix protein lacking a transmembrane segment (UniProt Q9BW92). | Recheck compartment boundaries with the counterstain and compare control sections; withhold a TARS2 assignment if the pattern persists (general IHC practice). |
| Nuclear staining accompanies cytoplasmic staining (HPA: tissue IHC profile). | HPA reports both compartments in tissue IHC, while the UniProt matrix annotation leaves the nuclear component unresolved (HPA: tissue IHC; UniProt Q9BW92). | Score nuclear and cytoplasmic signal separately, document the discrepancy, and avoid using nuclear staining alone as a specificity criterion (general IHC practice). |
| Sections in one run differ greatly in intensity (general IHC practice). | Uneven reagent coverage, development or section quality can complicate comparison (general IHC practice). | Review staining and counterstain uniformity, then compare matched cell types with a reference section processed in the same run (general IHC practice). |
Experiment evidence
IHC & IF images showing TARS2 staining
A12437 · IHCIHC analysis of TARS2 using anti-TARS2 antibody (A12437). TARS2 was detected in a paraffin-embedded section of human colonic adenocarcinoma
A12437 · IHCIHC analysis of TARS2 using anti-TARS2 antibody (A12437). TARS2 was detected in a paraffin-embedded section of human lung cancer tissue. Hea
A12437 · IFIF analysis of TARS2 using anti-TARS2 antibody (A12437). TARS2 was detected in an immunocytochemical section of T-47D cells. Enzyme antigen
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000143374-TARS2/tissue/cerebral+cortex#imid_7225747
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000143374-TARS2/tissue/colon#imid_7225663
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000143374-TARS2/tissue/liver#imid_7225656
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000143374-TARS2/tissue/kidney#imid_7225657
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA028626; green = TARS2, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA028626; green = TARS2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for TARS2 IHC & IF
🧪Run kidney first and look for staining in tubular cells (HPA: High in kidney cells in tubules). HPA detects TARS2 in all 45 scored tissues, so there is no supported negative tissue; use no-primary and isotype slides as negative controls, while any unstained cells within the kidney section should show counterstain without DAB and should not be assumed to lack TARS2 (HPA: no negative rows).
Positive control tissue: Gallbladder (Glandular cells, HPA High)
Negative control tissue: None in HPA: TARS2 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 TARS2 in A-431, U-251MG, U2OS, with annotated localisation: Nucleoplasm (uncertain), Cytosol (uncertain) (HPA subcellular).
Technical controls: Include a no-primary (secondary-only) control, a rabbit IgG isotype control matched to the primary antibody’s clonality, and TARS2-knockout material or an immunizing-peptide competition control if available (caption: rabbit primary; standard IHC practice). Block endogenous peroxidase and assess endogenous biotin background in kidney tubules when using the caption’s biotinylated secondary and SABC-DAB detection (caption: biotinylated secondary and SABC-DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A12437 paraffin-section caption does not state a fixative (caption: fixative not stated). The caption uses heat-mediated EDTA retrieval at pH 8.0, but whether retrieval is required for TARS2 is unreported (caption: EDTA retrieval, pH 8.0). The supplied evidence does not establish that frozen sections or tissue IF are easier; kidney tubular staining with biotin-based detection warrants attention to endogenous biotin background (HPA: High in kidney cells in tubules; caption: SABC-DAB; standard IHC practice).
HPA tissue IHC evidence for TARS2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Medium consistency between antibody staining and RNA expression data. Pending external verification.). 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 |
|---|---|---|---|---|
| Gallbladder | Glandular cells | High | Protein (IHC) | HPA → |
| Kidney | Cells in tubules | High | Protein (IHC) | HPA → |
| Rectum | Glandular cells | High | Protein (IHC) | HPA → |
| Small intestine | Glandular cells | High | Protein (IHC) | HPA → |
| Thyroid gland | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: TARS2 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced TARS2 IHC Tips
Troubleshoot TARS2 chromogenic IHC in paraffin sections by checking retrieval, staining compartment, background controls and cell-level scoring.
Which antigen retrieval conditions should I start with for TARS2 paraffin-section IHC?
Start with heat-mediated antigen retrieval in EDTA at pH 8.0 for paraffin sections (caption A12437). Keep the buffer and heating method consistent across comparison slides, and record the heating and cooling times because the caption does not specify them (caption A12437; standard IHC practice). If staining is weak, test a modest range of heating times on adjacent sections while holding antibody concentration and detection constant; excessive heating can damage morphology (standard IHC practice). The reported image used 2 μg/ml primary antibody overnight at 4°C, so changes to retrieval can be assessed against a documented staining condition (caption A12437).
How should I troubleshoot variable staining caused by fixation?
The selected image shows a paraffin-embedded section, but its fixative is unreported; target-specific fixation sensitivity is therefore unknown (caption A12437). Record each specimen’s fixative and fixation duration, then compare similarly processed sections before attributing a staining difference to TARS2 abundance (standard IHC practice). If archival samples vary in processing history, include a consistently handled reference section in each run and judge staining alongside preserved tissue morphology (standard IHC practice). Adjust fixation and retrieval as separate variables in any prospective comparison, since this caption supports pH 8.0 EDTA retrieval but supplies no fixation condition (caption A12437).
Should TARS2 staining be cytoplasmic, nuclear, or mitochondrial?
TARS2 is annotated as a mitochondrial matrix protein without a transmembrane segment, so assess whether cytoplasmic DAB staining has a plausible intracellular distribution (UniProt Q9BW92). HPA tissue IHC reports ubiquitous cytoplasmic and nuclear staining, while its ICC/IF nucleoplasm and cytosol assignments are marked uncertain (HPA tissue IHC; HPA subcellular). Chromogenic sections cannot reliably resolve individual mitochondria, so a diffuse cytoplasmic signal alone does not establish matrix localisation (standard IHC practice). Score cytoplasmic and nuclear staining separately, and investigate strong nuclear-only signal with controls and an independent localisation method before treating it as established TARS2 biology (UniProt Q9BW92; HPA subcellular; standard IHC practice).
Could isoforms or epitope accessibility explain discordant TARS2 staining?
TARS2 has 2 annotated isoforms, a TGS domain at residues 55–121, and a reported phosphoserine at residue 52 (UniProt Q9BW92). The supplied caption does not identify the A12437 epitope, so it cannot establish which isoforms or modified states the antibody detects (caption A12437; UniProt Q9BW92). When staining differs between specimens, request the immunogen or epitope details and check whether that sequence is shared before proposing isoform-specific expression (standard IHC practice). Compare serial sections under the same pH 8.0 EDTA retrieval and detection conditions first, because accessibility and processing can also change apparent staining (caption A12437; standard IHC practice).
How can IF help resolve uncertain TARS2 localisation in tissue?
For multiplex IF, pair TARS2 with a cell-identity marker appropriate to the sampled compartment, such as an epithelial marker when assessing glandular cells (HPA tissue IHC; standard IF practice). Choose spectrally separated fluorophores and consider a far-red channel for the weaker signal if tissue autofluorescence compromises shorter wavelengths (standard IF practice). Because TARS2 is annotated in the mitochondrial matrix and has no transmembrane segment, permeabilisation must allow access beyond the plasma membrane if the antibody recognizes an internal mitochondrial epitope; the epitope itself is unspecified (UniProt Q9BW92; caption A12437). Titrate detergent, include single-stain controls, and compare the resulting pattern with the uncertain nucleoplasm and cytosol ICC/IF assignments (HPA subcellular; standard IF practice).
What should I check when TARS2 DAB staining is widespread or granular?
The reported IHC image used 10% goat serum blocking, a biotinylated secondary, streptavidin–biotin detection and DAB (caption A12437). Run a no-primary control through the same detection steps to identify background from the detection system, and include a peroxidase block in the chromogenic workflow (standard IHC practice). If granular signal persists in the no-primary control, evaluate endogenous biotin or deposited chromogen before increasing the primary antibody concentration (caption A12437; standard IHC practice). Compare background and morphology on adjacent sections while titrating the reported 2 μg/ml primary condition, since broad cytoplasmic staining is also described in tissue IHC (caption A12437; HPA tissue IHC).
How should I quantify TARS2 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, because HPA describes cytoplasmic and nuclear tissue staining and lists high signal in several glandular populations (HPA tissue IHC). For each compartment, record the percentage of positive cells and intensity grades, then calculate an H-score from 0–300 using percentages at intensities 0–3 (standard IHC practice). Normalise cell-based scores to the number of evaluable cells; for area-based analysis, report positive cells or stained area per mm² of viable tissue (standard IHC practice). Apply one threshold and imaging setup across the batch, excluding folds and necrotic regions consistently (standard IHC practice).
How can I distinguish credible TARS2 staining from artefact?
A credible pattern should occur in intact cells and be assessed against the mitochondrial matrix annotation, the reported cytoplasmic and nuclear tissue profile, and the uncertain ICC/IF localisation assignments (UniProt Q9BW92; HPA tissue IHC; HPA subcellular). HPA reports high staining in kidney tubule cells and several glandular populations, while smooth muscle cells are listed as low; use those observations as context rather than absolute positive or negative controls (HPA tissue IHC). Distrust signal restricted to section edges, folds, necrosis or extracellular deposits, and check a no-primary slide for endogenous enzyme or detection background (standard IHC practice). Reconcile strong nuclear-only or unexpected cell-specific staining with morphology and an independent assay before assigning biological meaning (UniProt Q9BW92; standard IHC practice).
Boster reagents
Best TARS2 / Threonine--tRNA ligase, mitochondrial IHC Antibodies
A12437 has IHC images from human colonic adenocarcinoma, human lung cancer, and rat brain paraffin sections, plus IF data from T-47D cells (A12437 image captions).
Real IHC data
Anti-TARS2 Antibody ®
Cat # A12437
A12437 is listed for IHC and IF/ICC (catalog applications); its IHC images show human colonic adenocarcinoma, human lung cancer, and rat brain paraffin sections (A12437 IHC captions). Its IF image shows T-47D cells (A12437 IF caption), and its listed reactivity is human, mouse, and rat (catalog reactivity).
Which to pick: Choose A12437 for paraffin-section IHC: its images document staining in human and rat tissues (A12437 IHC captions); the fixative is unreported (A12437 IHC captions). Choose A12437 for IF/ICC in T-47D cells (A12437 IF caption; catalog applications). For cross-species work, A12437 lists human, mouse, and rat reactivity (catalog reactivity), while the pictured IHC evidence covers human and rat tissue and the IF evidence covers T-47D cells (A12437 image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9BW92 (SYTM_HUMAN, Threonine--tRNA ligase, mitochondrial).
- Human Protein Atlas. TARS2 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. TARS2 subcellular location (ICC-IF): Localized to the nucleoplasm and cytosol..
- Human Protein Atlas. TARS2 antibody validation summary (1 antibodies).
- Knockdown of mitochondrial threonyl-tRNA synthetase 2 inhibits lung adenocarcinoma cell proliferation and induces apoptosis. Bioengineered 2022 — PMC8974053.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:16710414 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for TARS2 (Threonine--tRNA ligase, mitochondrial). Expected localisation Cytoplasmic/nuclear staining (HPA tissue IHC); mitochondrial matrix protein (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A12437). Validated IHC antibody: A12437 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Gallbladder (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 colonic adenocarcinoma tissue; fixative not specified (datasheet A12437); 2. Fixation: Image fixative and duration unreported (datasheet A12437); 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 A12437); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A12437); 8. Primary antibody: Rabbit anti-TARS2, 2-5 μg/ml (datasheet A12437); 9. Primary incubation: Overnight at 4 °C (datasheet A12437). Watch for: Fixation: Keep paraffin-section fixation consistent (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A12437); Caveat: Staining has medium consistency with RNA expression (HPA tissue IHC); Isoform / epitope: 2 isoforms; epitope effects are unresolved (UniProt); Regulation: No expression regulator reported (UniProt). Evidence: UniProt Q9BW92, HPA tissue IHC · Approved, HPA ICC-IF · nucleoplasm and cytosol., Datasheet A12437, PMC8974053. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/TARS2/immunohistochemistry-ihc-guide.