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TGM2 / Protein-glutamine gamma-glutamyltransferase 2 · IHC design guide
Design Immunohistochemistry for TGM2
Plan TGM2 paraffin IHC around cytoplasmic staining in placental decidual cells and endometrial stromal fibroblasts (HPA tissue IHC). Score cellular and extracellular staining separately because TGM2 can be secreted to the extracellular matrix (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 | Cytoplasmic in tissue (HPA tissue IHC); extracellular matrix localization also reported (UniProt) | |
| Staining pattern | Cytoplasmic staining in decidual cells and stromal fibroblasts (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) | |
| Caveat | Secreted TGM2 may produce extracellular matrix staining (UniProt) | |
| Regulation | Staining regulation not specified (UniProt) | |
| Isoform / epitope | 3 isoforms; epitope coverage and compartment bias unknown (UniProt) |
Section 1
Recommended TGM2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is accompanied by published TGM2 methods for renal, meningioma, and colorectal specimens (PMC3292891; PMC5697495; 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 noteFor paraffin sections, start with Tris-EDTA pH 9.0 HIER at 95–98 °C for 20 min (page antigen-retrieval setting).
Section 2
What Is the Expected TGM2 Staining Pattern?
TGM2 should stain mainly in the cytoplasm, with prominent IHC signal in endometrial stromal fibroblasts and placental decidual cells (HPA: Enhanced tissue IHC; High in both cell types). Cytosol is its main location; lower nuclear signal and extracellular matrix localization are possible (UniProt P21980: subcellular location). TGM2 has no transmembrane segment (UniProt P21980: topology).
| Strong cytoplasmic staining in endometrial stromal fibroblasts or placental decidual cells. | This matches the clearest reported tissue pattern (HPA: High in both cell types; Enhanced tissue IHC). Score the named cells separately from adjacent structures, since a tissue-level result can conceal cell-specific differences (general IHC practice). |
| Cytoplasmic staining in cardiomyocytes, alveolar cells, or smooth muscle cells. | A moderate signal is consistent with the reported pattern (HPA: Medium in these cell types). Weaker staining than in the High examples can still be expected; compare like-for-like sections and detection settings before interpreting intensity differences (HPA: tissue IHC; general IHC practice). |
| Predominantly intense nuclear staining with little or no cytoplasmic signal. | Review this as a possible compartment artefact: TGM2 is mainly cytosolic, although lower nuclear and chromatin localization is reported (UniProt P21980: subcellular location). Nuclear staining alone cannot prove specificity; check an appropriate control and the accompanying cytoplasmic pattern (general IHC practice). |
| Strong staining in a cell population reported as Not detected, such as adrenal glandular cells. | The pattern conflicts with the HPA observation for that cell type (HPA: adrenal glandular cells, Not detected). Cross-reactivity or endogenous chromogenic detection activity is possible; verify the stained cells and compare a no-primary control (general IHC practice). |
| Diffuse color across cells, stroma, and section edges, or no signal in a known-positive section. | A pattern without cell-level localization suggests background, while absence from a High reference population makes the run difficult to interpret (general IHC practice; HPA: High in endometrial stromal fibroblasts and placental decidual cells). Check controls before assigning either result to TGM2 expression (general IHC practice). |
💡Expected TGM2 appearanceCall an IHC result positive when cytoplasmic staining is clear in endometrial stromal fibroblasts or placental decidual cells at the reported High level; diffuse color without cell-level localization is suspect (HPA: tissue IHC; general IHC practice).
| Tissue and cell selection | Endometrial stromal fibroblasts and placental decidual cells offer High reference patterns; HPA reports Not detected in several specific cell populations, including adrenal glandular cells (HPA: tissue IHC). Interpret each named cell population rather than treating an entire organ as uniformly positive or negative (general IHC practice). |
| Compartment and extracellular signal | Cytosol is the principal location; lower nuclear and chromatin localization and secretion to extracellular matrix are also reported (UniProt P21980: subcellular location). Matrix-associated color may warrant review, but it should be judged against tissue structure and controls before being assigned to TGM2 (general IHC practice). |
| Protein topology and processing | TGM2 has no transmembrane segment or signal peptide and is reported to reach extracellular matrix by a non-classical secretion pathway (UniProt P21980: topology, processing, subcellular location). Membrane-associated staining is therefore possible without interpreting TGM2 as a membrane-spanning protein (UniProt P21980: topology; HPA: ICC-IF plasma membrane localization). |
| IHC antibody validation | Three listed antibodies have Enhanced IHC status; this supports the reported tissue pattern through independent antibodies or orthogonal data (HPA: antibody validation). It does not establish that every antibody or detection setup will produce identical intensity (HPA: antibody validation; general IHC practice). |
| IF/ICC: where should signal appear? | Mainly in the cytosol, with additional plasma membrane localization in the HPA ICC-IF record (HPA: subcellular location, approved). This describes the expected IF/ICC compartment and does not specify an IF/ICC protocol or establish an identical appearance in paraffin IHC (HPA: ICC-IF; general IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| No signal in endometrial stromal fibroblasts or placental decidual cells. | These cells are reported High, so absent staining raises a run or specimen concern; it does not by itself establish loss of TGM2 (HPA: tissue IHC; general IHC practice). | Review the positive control, antibody dilution, retrieval and detection steps, then repeat with a matched known-positive section if needed (general IHC practice). |
| Strong nuclear signal dominates while cytoplasm remains pale. | This differs from the mainly cytosolic pattern, although lower nuclear localization is documented (UniProt P21980: subcellular location). | Inspect morphology and the no-primary control; compare a known-positive section before accepting nuclear staining as specific (general IHC practice). |
| Color appears in HPA Not detected cells. | Cell identification, cross-reactivity, or endogenous detection activity may explain a discordant result (HPA: tissue IHC; general IHC practice). | Confirm the cell type, examine a no-primary control, and review the detection-blocking step appropriate to the chromogen system (general IHC practice). |
| Diffuse color obscures the cytoplasmic pattern. | Nonspecific background can prevent cell-level interpretation (general IHC practice). | Check no-primary and reagent controls, then review blocking, washes, antibody dilution and development time (general IHC practice). |
| Extracellular or membrane-edge color is the only apparent signal. | TGM2 can occur in extracellular matrix, and ICC-IF also reports plasma membrane localization; color at an edge alone remains ambiguous (UniProt P21980: subcellular location; HPA: ICC-IF). | Check whether staining follows recognizable matrix or cell boundaries and whether the positive control shows the expected cytoplasmic signal (general IHC practice; HPA: tissue IHC). |
| A section gives weaker staining than the High reference tissue. | Some HPA-listed cell types are Medium or Low, and intensity also depends on the staining run (HPA: tissue IHC; general IHC practice). | Compare the same cell type under matched conditions and retain a High reference section in the run before calling the weaker result negative (HPA: tissue IHC; 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 in adrenal gland glandular cells); cells serving as internal negatives on the endometrial slide should show counterstain without specific chromogen deposit (standard IHC practice).
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; nonimmune immunoglobulin matched to the primary antibody’s host and isotype, including subclass if monoclonal; and TGM2 knockout material processed alongside the samples if available (standard IHC practice). For chromogenic detection, quench endogenous peroxidase and check for residual background on the no-primary endometrial section (standard IHC practice).
⚠️Feasibility: A target-specific fixation window and retrieval dependency are unreported in the supplied evidence; the PA2153 IHC(P) human lung cancer tissue caption does not report a fixative (PA2153 tissue-IHC caption). These data do not establish whether frozen sections or IF are easier than paraffin IHC (PA2153 tissue-IHC caption; HPA subcellular ICC-IF images). Blood-associated peroxidase can complicate endometrial chromogen scoring, so compare with the no-primary section (standard IHC practice).
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
Use compartment and cell type controls to interpret TGM2 staining in paraffin section IHC (UniProt P21980 localisation; HPA tissue IHC).
How should I retrieve TGM2 when staining is weak?
Use Tris-EDTA pH 9.0 heat induced epitope retrieval at 95–98 °C for 20 min (page retrieval specification). Compare retrieved and unretrieved serial sections while keeping antibody concentration, detection chemistry, and imaging conditions constant (standard IHC practice). If staining remains weak, test an alternative retrieval buffer only as a fallback, and judge it against a positive cell population such as endometrial stromal fibroblasts (HPA: High in endometrial stromal fibroblasts). Check tissue integrity and background alongside signal, because excessive retrieval can damage section morphology and complicate compartment scoring (standard IHC practice).
Could fixation explain weak or uneven TGM2 staining?
Target specific fixation sensitivity is unknown because the supplied TGM2 tissue IHC caption does not state a fixative (PA2153 IHC(P) caption). Record the specimen’s fixative, fixation duration, processing history, and section age before comparing cases (standard IHC practice). For weak or uneven staining, compare sections processed under matched conditions and inspect morphology for poor preservation or uneven reagent penetration (standard IHC practice). Keep retrieval and detection conditions constant during that comparison, then adjust one workflow variable at a time; neither tissue staining patterns nor TGM2 topology establishes a fixation requirement (standard IHC practice; UniProt P21980 topology).
Which TGM2 staining compartments should I expect in tissue sections?
Assess cytoplasmic staining first: TGM2 is mainly cytosolic, with lower nuclear and chromatin abundance, and can also occur at the cell membrane and in extracellular matrix (UniProt P21980 localisation). HPA describes cytoplasmic tissue staining and approves cytosol as the main subcellular location, with plasma membrane as an additional location (HPA tissue IHC; HPA subcellular). Score nuclear, membrane associated, and extracellular signal separately from cytoplasmic signal rather than combining them into one intensity grade (standard IHC practice). Use cell morphology and a matched control section to check whether an unexpected compartment persists under consistent detection conditions (standard IHC practice).
Why might antibodies disagree on the TGM2 staining pattern?
TGM2 has 3 listed isoforms and no annotated transmembrane segment, so an antibody’s recognised epitope matters when comparing staining patterns (UniProt P21980 isoforms and topology). Check the antibody’s stated immunogen or epitope, if available, before treating divergent staining as biological variation (standard IHC practice). Retrieval can alter epitope accessibility in paraffin sections, so compare antibodies under documented retrieval conditions and inspect the same cell populations and compartments (standard IHC practice). The listed N acetylation, phosphoserine, and acetyllysine sites do not establish that the catalog antibody distinguishes modified TGM2; require direct epitope evidence for that claim (UniProt P21980 modified residues; standard IHC practice).
How can I check TGM2 localisation by multiplex IF?
Use IF as a separate localisation check alongside chromogenic IHC, pairing TGM2 with a validated marker for the cell population being assessed, such as a stromal fibroblast marker in endometrium (HPA: High in endometrial stromal fibroblasts; standard IF practice). Select spectrally separated fluorophores and place the weaker signal in a channel less affected by the specimen’s autofluorescence (standard IF practice). For cytosolic or nuclear epitopes, optimise permeabilisation after fixation; for an accessible cell surface epitope, compare with a nonpermeabilised condition (UniProt P21980 localisation; standard IF practice). Include single colour and secondary only controls before interpreting apparent overlap as colocalisation (standard IF practice).
How do I distinguish TGM2 signal from chromogenic background?
Inspect a section processed without primary antibody to assess detection background, and compare it with an antibody stained serial section using the same exposure to chromogen (standard IHC practice). Block endogenous peroxidase before HRP and DAB detection, then check whether diffuse colour persists in the control section (standard IHC practice). If staining is widespread, optimise antibody concentration, blocking, wash conditions, and chromogen development one variable at a time (standard IHC practice). Evaluate background separately in cytoplasm and extracellular matrix, because TGM2 can occur in both locations and a blanket background subtraction could remove plausible signal (UniProt P21980 localisation; standard IHC practice).
How should I quantify TGM2 across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the compartment and cell population before scoring: HPA reports cytoplasmic staining in several tissues, while TGM2 can also occur extracellularly (HPA tissue IHC; UniProt P21980 localisation). For cellular staining, report the percentage of positive cells and an H-score derived from intensity categories; normalise counts to the number of evaluable cells in the defined region (standard IHC practice). For extracellular staining, report stained area or density per mm² of evaluable tissue, separately from the cellular score (standard IHC practice). Apply one threshold across batches using reference sections, and exclude folds, tears, and necrotic areas from the measured denominator (standard IHC practice).
What would make a TGM2 positive result unconvincing?
A plausible positive pattern includes cytoplasmic staining in expected cells, such as endometrial stromal fibroblasts or placental decidual cells, with possible membrane or extracellular signal (HPA tissue IHC; UniProt P21980 localisation). Treat isolated intense nuclear staining cautiously because TGM2 is mainly cytosolic and occurs at much lower levels in the nucleus and chromatin (UniProt P21980 localisation). Check abrupt section edge staining, necrotic areas, and signal in morphologically unexpected cells against adjacent intact tissue and matched controls (standard IHC practice). If colour persists without primary antibody, investigate endogenous peroxidase activity or detection reagents before assigning it to TGM2 (standard IHC practice).
Boster reagents
Best TGM2 / Protein-glutamine gamma-glutamyltransferase 2 IHC Antibodies
Catalog images document TGM2 IHC in human cancer tissues and mouse and rat spleen (PA2153 and PB9448 image captions). PA2153 lists ICC, but supplies no IF image (PA2153 catalog).
Real IHC data
Anti-Transglutaminase 2/TGM2 Antibody ®
Cat # PA2153
PA2153 is the only rendering SKU; its own IHC(P) image shows human lung cancer tissue (PA2153 image caption). It lists Human/Rat reactivity and ICC as an application, without an IF image (PA2153 catalog).
Which to pick: Choose PA2153 for human paraffin-section IHC because its own image documents human lung cancer tissue; the fixative is unreported (PA2153 image caption). For ICC, PA2153 lists 0.5–1 μg/ml, but supplies no IF image (PA2153 catalog). For cross-species tissue IHC, PB9448 lists Human/Mouse/Rat reactivity and has paraffin-section images from human cancers and mouse and rat spleen; those captions do not report the fixative (PB9448 catalog and 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 Cytoplasmic in tissue (HPA tissue IHC); extracellular matrix localization also reported (UniProt). 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); Caveat: Secreted TGM2 may produce extracellular matrix staining (UniProt); Isoform / epitope: 3 isoforms; epitope coverage and compartment bias unknown (UniProt); Regulation: Staining regulation not specified (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.