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TGM2 / Protein-glutamine gamma-glutamyltransferase 2 · IHC design guide
Design Immunohistochemistry for TGM2
Plan TGM2 staining in paraffin sections using endometrial stromal fibroblasts and placental decidual cells as high-staining reference cells (HPA tissue IHC). This guide covers the expected cytoplasmic pattern (HPA tissue IHC), consistent fixation (standard IHC practice), and possible extracellular matrix signal (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
TGM2 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 | Predominantly cytoplasmic in tissue sections (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic in placenta, endometrium and smooth muscle (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen) | |
| Positive control | Endometrium+4 more · see all | |
| Negative control | Adrenal gland+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific). Selected-image fixative and duration unreported (datasheet PA2153); verify before use. | |
| Caveat | Secreted TGM2 may produce extracellular matrix signal (UniProt) | |
| Regulation | Expression regulation not annotated (UniProt) | |
| Isoform / epitope | Three isoforms; epitope differences are unverified (UniProt) |
Section 1
Recommended TGM2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet) appears alongside published TGM2 IHC protocols from renal, meningioma, and colorectal samples (PMC3292891; PMC5697495; PMC4172767; PMC10581896).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet PA2153); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat-induced epitope retrieval in Tris-EDTA buffer, pH 9.0, 20 min at 95–98 °C (standard rule: nuclear antigen) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% normal serum of the secondary host, 30 min, room temperature (standard) |
| Primary antibody | Rabbit anti-TGM2, 0.5-1μg/ml (datasheet PA2153) |
| Primary incubation | Overnight at 4 °C (standard) |
| Detection | HRP-polymer secondary, DAB chromogen 5–10 min (standard) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | TGM2-positive staining in stromal fibroblasts of endometrium (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic staining mainly in placenta, endometrium, fibromuscular tissue and smooth muscle. No signal in the no-primary control. |
💡Decision noteStart with Tris-EDTA pH 9.0 heat retrieval at 95–98 °C for 20 min (page retrieval setting); optimize with tissue controls (standard IHC practice).
Section 2
What Is the Expected TGM2 Staining Pattern?
TGM2 is mainly cytosolic, with smaller nuclear and extracellular pools and no transmembrane segment (UniProt P21980). In paraffin IHC, expect cytoplasmic staining in endometrial stromal fibroblasts and placental decidual cells, both rated High (HPA: tissue IHC). HPA rates the tissue staining pattern Enhanced (HPA: reliability).
| Strong cytoplasm in endometrial stromal fibroblasts | Expected positive pattern (HPA: High in endometrial stromal fibroblasts). |
| Predominantly nuclear staining | Question the pattern: nuclear TGM2 is much lower than cytosolic TGM2 (UniProt P21980). |
| Glandular staining in adrenal gland | Unexpected (HPA: glandular cells not detected); check nonspecific binding or endogenous detection activity. |
| Diffuse haze across cells and matrix | Cell-specific staining is hard to judge; review blocking and washes (general IHC practice). |
| No signal in placental decidual cells | Unexpected (HPA: High in decidual cells); check the staining run before scoring negative. |
💡Expected TGM2 appearanceA positive slide shows strong cytoplasm in endometrial stromal fibroblasts or placental decidual cells (HPA: High); uniform haze suggests background (general IHC practice).
| Cell type | Endometrial stromal fibroblasts and placental decidual cells are High (HPA: tissue IHC). |
| Compartment | Cytosol predominates; nuclear TGM2 is much lower (UniProt P21980). |
| Extracellular TGM2 | Matrix staining can be plausible because TGM2 is secreted (UniProt P21980). |
| Antibody validation | HPA021019, HPA029518 and CAB002598 are IHC Enhanced (HPA: antibodies). |
| IF/ICC pattern? | Mainly cytosol, with plasma membrane also observed (HPA: approved ICC-IF locations). |
| Situation | Likely cause | Next action |
|---|---|---|
| No stain in endometrial stromal fibroblasts | Unexpected for a High cell type (HPA: tissue IHC). | Check positive control, retrieval and detection steps (general IHC practice). |
| Diffuse chromogen across the section | Blocking, washing or detection background may obscure cells (general IHC practice). | Review blocking, washes and detection controls (general IHC practice). |
| Adrenal glandular cells stain strongly | Unexpected: HPA reports these cells as not detected (HPA: tissue IHC). | Check no-primary control and nonspecific binding (general IHC practice). |
| Nuclear signal dominates | Nuclear TGM2 is normally much lower than cytosolic TGM2 (UniProt P21980). | Compare with cytoplasmic staining and controls (general IHC practice). |
| Extracellular deposits appear | Secreted TGM2 can localize to matrix (UniProt P21980). | Assess deposits alongside cell staining and controls (general IHC practice). |
| All cells appear equally dark | Overdeveloped chromogen may hide cell differences (general IHC practice). | Shorten chromogen development and compare controls (general IHC practice). |
Experiment evidence
IHC & IF images showing TGM2 staining
PA2153 · IHCAnti-TGM2 antibody, PA2153, IHC(P) IHC(P): Human Lung Cancer Tissue
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000198959-TGM2/tissue/cerebral+cortex#imid_7478697
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000198959-TGM2/tissue/colon#imid_7478631
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000198959-TGM2/tissue/liver#imid_7478624
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000198959-TGM2/tissue/kidney#imid_7478633
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB002598; green = TGM2, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB002598; green = TGM2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for TGM2 IHC & IF
🧪Run endometrium first: stromal fibroblasts should stain (HPA: High in endometrial stromal fibroblasts); use adrenal gland glandular cells as the negative tissue (HPA: Not detected). Cells outside the stromal fibroblast population on the positive slide are candidate internal negatives, but their expected staining is not specified by the supplied HPA rows; assess them by morphology before treating them as negative (HPA: endometrium row).
Positive control tissue: Endometrium (Stromal fibroblasts, HPA High)
Negative control tissue: Adrenal gland (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show TGM2 in A-431, U-251MG, U2OS, with annotated localisation: Cytosol (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and host-species-matched nonimmune IgG for a polyclonal primary or an isotype-matched control for a monoclonal primary (standard IHC practice). Use TGM2-knockout material as a biological negative where available, or an immunizing-peptide block if the peptide is available; check endogenous peroxidase in the chromogenic endometrium section (standard IHC practice).
⚠️Feasibility: A target-specific fixation window and antigen-retrieval requirement are unreported in the supplied evidence; the selected PA2153 IHC(P) lung-cancer caption does not state a fixative (PA2153 caption). These data do not establish whether frozen sections or IF are easier than paraffin IHC, although ICC-IF images are available for A-431, U-251MG and U2OS (HPA: subcellular). Extracellular staining may complicate assignment of signal to endometrial stromal fibroblasts because TGM2 can be secreted to the extracellular matrix (UniProt P21980: subcellular location).
HPA tissue IHC evidence for TGM2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High consistency between antibody staining and RNA expression data. At least one protein variant secreted, tissue location of RNA and protein might differ and correlation is complex. Antibody staining in cells/structures not annotated, view images.). 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 |
|---|---|---|---|---|
| Endometrium | Stromal fibroblasts | High | Protein (IHC) | HPA → |
| Placenta | Decidual cells | High | Protein (IHC) | HPA → |
| Heart muscle | Cardiomyocytes | Medium | Protein (IHC) | HPA → |
| Lung | Alveolar cells | Medium | Protein (IHC) | HPA → |
| Smooth muscle | Smooth muscle cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced TGM2 IHC Tips
Troubleshoot TGM2 staining in paraffin sections by checking retrieval, compartment, cell type and controls before assigning biological meaning.
How should I retrieve TGM2 when paraffin sections stain weakly?
Start with Tris-EDTA at pH 9.0, heated to 95–98 °C for 20 min (page retrieval setting). Let sections cool in buffer, then compare staining with a matched section processed in the same run; keep detection conditions identical when judging retrieval (standard IHC practice). If staining remains weak, test a shorter heating interval or an alternative retrieval buffer as a fallback, while watching for tissue loss and diffuse background (standard IHC practice). Score cytoplasmic signal in stromal fibroblasts of endometrium or decidual cells of placenta as reference patterns, without assuming every cell in those tissues must stain (HPA: High in those cell types).
Could fixation explain weak or uneven TGM2 staining?
Target-specific sensitivity of TGM2 to fixation is unknown from the supplied evidence; the selected PA2153 lung cancer caption reports IHC(P) but does not state a fixative (PA2153 IHC(P) caption). Record the actual fixative, fixation duration, section thickness and storage history for each case before comparing staining intensity (standard IHC practice). Use sections with matched processing and the same Tris-EDTA pH 9.0, 95–98 °C, 20 min retrieval to assess whether weak staining tracks with a processing batch (page retrieval setting; standard IHC practice). Interpret any batch association as a troubleshooting clue, then verify it with a repeat section and an appropriate positive control (standard IHC practice).
Should TGM2 stain cytoplasm, nuclei or extracellular matrix?
Expect cytoplasmic staining as the main tissue pattern, particularly in endometrium, placenta, fibromuscular tissue and smooth muscle (HPA: tissue IHC profile). Cytosol is the main approved subcellular location, with plasma membrane also approved; UniProt additionally lists nucleus, perinuclear region, mitochondrion and extracellular matrix (HPA: subcellular; UniProt P21980: subcellular location). Assess nuclear or extracellular staining separately from cytoplasmic signal, because UniProt describes lower nuclear abundance and nonclassical secretion (UniProt P21980: subcellular location). For an unexpected compartment, inspect morphology and compare the same compartment in a no-primary control before reporting a new localization (standard IHC practice).
Can this antibody distinguish TGM2 isoforms or modified epitopes?
The record lists 3 TGM2 isoforms, but the supplied PA2153 caption does not identify an epitope or demonstrate isoform discrimination (UniProt P21980: isoforms; PA2153 IHC(P) caption). Treat chromogenic staining as TGM2-associated signal until antibody epitope mapping or isoform-specific validation establishes a narrower claim (standard IHC interpretation). UniProt records acetylation at residue 2, phosphorylation at 60 and acetylation at 468; their effects on this antibody's binding are unknown (UniProt P21980: modified residues). If cases disagree, compare staining under identical retrieval and detection conditions, and use an independently validated epitope or orthogonal assay to investigate the discrepancy (standard IHC practice).
How can I check TGM2 staining by multiplex immunofluorescence?
Use IF as a separate validation experiment, pairing TGM2 with a validated marker for the cell population being examined, such as the stromal fibroblasts or decidual cells reported positive in tissue IHC (HPA: High in those cell types; standard IF practice). Select spectrally separated fluorophores after inspecting unstained tissue, and place the weaker signal in a channel with less tissue autofluorescence (standard IF practice). For a cytosolic epitope, test gentle permeabilisation, such as 0.1% Triton X-100 for 5 min; a surface-facing epitope may be assessed without permeabilisation (HPA: cytosol and plasma membrane; standard IF practice). Include single-color and no-primary controls before comparing IF with chromogenic IHC (standard IF practice).
What causes diffuse brown staining in TGM2 IHC?
First examine a no-primary section to separate detection-system background from antibody-dependent staining, and inspect tissue edges and damaged areas independently (standard IHC practice). For peroxidase detection, a 3% hydrogen peroxide block for about 10 min and thorough washes can help assess endogenous enzyme contribution; these are general workflow steps, not TGM2-specific evidence (standard IHC practice). Titrate the primary antibody and detection reagent against a positive reference section, because excess reagent can obscure cell boundaries (standard IHC practice). Retain plausible cytoplasmic and extracellular patterns for evaluation, since TGM2 is chiefly cytosolic but can reach the extracellular matrix (UniProt P21980: subcellular location).
How should I score TGM2 staining across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, then record the percentage of positive cells and cytoplasmic intensity on a 0–3 scale (standard IHC practice; HPA: cytoplasmic tissue profile). An H-score sums each intensity category multiplied by its percentage, yielding 0–300; report the scoring rule and any threshold used (standard IHC practice). For extracellular staining, measure positive area per tissue area or signal density per mm² within a defined region instead of assigning that signal to nearby cells (standard IHC practice; UniProt P21980: extracellular matrix). Normalize cell-based results to eligible cells and area-based results to evaluable tissue area, excluding folds, necrosis and section edges consistently (standard IHC practice).
How do I distinguish genuine TGM2 signal from artefact?
A convincing result follows interpretable cell boundaries and a plausible compartment: cytoplasm is the principal tissue pattern, while plasma membrane and extracellular signal can also occur (HPA: tissue IHC profile; HPA: subcellular; UniProt P21980: subcellular location). Check whether staining lies in the relevant cells; HPA reports high signal in endometrial stromal fibroblasts and placental decidual cells, but those observations do not make every cell positive (HPA: tissue IHC). Treat edge-only staining, necrotic debris or signal reproduced in a no-primary section as possible artefact (standard IHC practice). Compare serial sections and peroxidase-blocked controls before attributing unexpected brown deposits to TGM2 (standard IHC practice).
Boster reagents
Best TGM2 / Protein-glutamine gamma-glutamyltransferase 2 IHC Antibodies
The rendered anti-TGM2 card shows paraffin-section IHC in human lung cancer tissue (PA2153 image caption); the catalog lists human and rat reactivity (PA2153 applications/reactivity).
Real IHC data
Anti-Transglutaminase 2/TGM2 Antibody ®
Cat # PA2153
PA2153 is the sole SKU with a rendered card (cards payload). Its figure shows IHC in human lung cancer tissue, while its catalog entry lists IHC and ICC applications and human and rat reactivity (PA2153 image caption; PA2153 applications/reactivity).
Which to pick: Choose PA2153 for human tissue IHC when its paraffin-section example fits your sample; the caption does not report the fixative (PA2153 image caption). For IF/ICC, PA2153 lists ICC at 0.5–1 μg/ml, but no IF image is supplied (PA2153 applications/dilution; PA2153 IF image alts). For cross-species tissue IHC, PB9448 has the broadest listed reactivity—human, mouse and rat—and paraffin-section images from all three species; its captions do not report the fixative (PB9448 reactivity; PB9448 IHC image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P21980 (TGM2_HUMAN, Protein-glutamine gamma-glutamyltransferase 2).
- Human Protein Atlas. TGM2 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. TGM2 subcellular location (ICC-IF): Mainly localized to the cytosol. In addition localized to the plasma membrane..
- Human Protein Atlas. TGM2 antibody validation summary (3 antibodies).
- Tumor suppressive microRNA-1285 regulates novel molecular targets: aberrant expression and functional significance in renal cell carcinoma. Oncotarget 2012 — PMC3292891.
- Thioredoxin-Interact ing-Pro t e in [TXNIP] and Transglutaminase 2 [TGM2] Expression in Meningiomas of Different Grades and the Role of Their Expression in Meningioma Recurrence and Prognosis. Asian Pacific journal of cancer prevention : APJCP 2017 — PMC5697495.
- Transglutaminase 2 expression is increased as a function of malignancy grade and negatively regulates cell growth in meningioma. PloS one 2014 — PMC4172767.
- Transglutaminase 2 is associated with adverse colorectal cancer survival and represents a therapeutic target. Cancer gene therapy 2023 — PMC10581896.
- PubMed PMID:1670766 — UniProt-cited evidence.
- PubMed PMID:1358880 — UniProt-cited evidence.
- PubMed PMID:8611626 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for TGM2 (Protein-glutamine gamma-glutamyltransferase 2). Expected localisation Predominantly cytoplasmic in tissue sections (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen). Validated IHC antibody: PA2153 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Endometrium (Stromal fibroblasts); negative Adrenal gland. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet PA2153); 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-induced epitope retrieval in Tris-EDTA buffer, pH 9.0 , 20 min at 95–98 °C…; 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% normal serum of the secondary host, 30 min , room temperature (standard); 8. Primary antibody: Rabbit anti-TGM2, 0.5-1μg/ml (datasheet PA2153); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific). Selected-image fixative and duration unreported (datasheet PA2153); verify before use.; Caveat: Secreted TGM2 may produce extracellular matrix signal (UniProt); Isoform / epitope: Three isoforms; epitope differences are unverified (UniProt); Regulation: Expression regulation not annotated (UniProt). Evidence: UniProt P21980, HPA tissue IHC · Enhanced, HPA ICC-IF · Mainly localized to the cytosol. In addition localized to the plasma…, Datasheet PA2153, PMC3292891, PMC5697495. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/TGM2/immunohistochemistry-ihc-guide.