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GLUL / Glutamine synthetase · IHC design guide
Design Immunohistochemistry for GLUL
Plan GLUL chromogenic IHC on paraffin sections with the catalog antibody at 2–5 μg/ml (datasheet A03191-3). Assess cytoplasmic staining by cell type and liver zone (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
GLUL 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 tissue staining (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic in adipocytes, macrophages, glia; zonal in liver (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A03191-3) | |
| Positive control | Adipose tissue+4 more · see all | |
| Negative control | Adrenal gland+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A03191-3) | |
| Caveat | Pericentral hepatocyte enrichment can skew liver scoring (HPA tissue IHC) | |
| Regulation | Cell type and liver zone specific (HPA tissue IHC) | |
| Isoform / epitope | No annotated isoforms, signal peptide or propeptide (UniProt) |
Section 1
Recommended GLUL IHC & IF Protocols
The catalog antibody has a datasheet IHC-P protocol (datasheet A03191-3); the published pancreas protocol below provides an alternative (PMC6886125).
| Sample | Paraffin-embedded human appendiceal adenocarcinoma tissue; fixative not specified (datasheet A03191-3) |
| Fixation | Image fixative and duration unreported (datasheet A03191-3); 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 A03191-3); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A03191-3) |
| Primary antibody | Rabbit anti-GLUL, 2-5 μg/ml (datasheet A03191-3) |
| Primary incubation | Overnight at 4 °C (datasheet A03191-3) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A03191-3) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | GLUL-positive staining in adipocytes of adipose tissue (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in several different cell types. Distinct expression in adipocytes, macrophages, glial cells and in hepatocytes around the central vein. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA at pH 8.0 for the catalog antibody (datasheet A03191-3); the published pancreas protocol used citrate at pH 6.0 (PMC6886125).
Section 2
What Is the Expected GLUL Staining Pattern?
GLUL should show predominantly cytoplasmic staining in paraffin-section IHC: UniProt places it mainly in the cytosol, with a membrane-associated fraction and no transmembrane segment (UniProt P15104). Expect distinct signal in adipocytes, macrophages, glial cells, and hepatocytes around central veins (HPA tissue IHC). The tissue profile is Approved, with medium consistency between staining and RNA data and support from paired antibodies (HPA tissue IHC).
| Cytoplasmic staining in adipocytes or glial cells, with adjacent cells staining less strongly. | This matches the reported cell-selective pattern; adipocytes and glial cells are scored High in the listed tissues (HPA tissue IHC). Compare cells within the section rather than treating every unstained neighbor as a failed stain (general IHC practice). |
| Predominantly nuclear staining, or a sharp membrane-only outline with little cytoplasm. | Question this as a GLUL pattern: its main location is cytosolic, although a fraction associates with membrane (UniProt P15104). Nuclear localization is absent from the supplied localization records (UniProt P15104; HPA subcellular). Review controls and staining conditions before scoring such signal (general IHC practice). |
| Strong signal in a cell population reported as Not detected, such as heart cardiomyocytes. | That conflicts with the named cell population in the HPA profile; it does not make the entire heart a negative tissue (HPA tissue IHC). Consider cross-reactivity or endogenous chromogenic activity and check an appropriate detection control (general IHC practice). |
| Color spread across stroma, lumens, or most cells without clear cellular boundaries. | A broad haze is less consistent with the reported cell-selective cytoplasmic pattern (HPA tissue IHC). Background can arise from nonspecific binding or detection chemistry; inspect a control without primary antibody and review blocking and washing (general IHC practice). |
| No stain in adipocytes or glial cells in an otherwise interpretable section. | Those are useful positive reference populations because HPA reports High staining in adipocytes and glial cells in listed tissues (HPA tissue IHC). Check tissue identity, section quality, antibody and detection controls, and the validated IHC-P workflow before calling the specimen negative (general IHC practice). |
💡Expected GLUL appearanceCall a result positive when cell-selective, mainly cytoplasmic signal is clear in expected cells, especially High-scoring adipocytes or glial cells; isolated nuclear color or uniform tissue-wide haze warrants investigation (HPA tissue IHC; UniProt P15104; general IHC practice).
| Cell type and tissue region | HPA reports distinct hepatocyte staining around central veins and High staining in adipocytes and glial cells (HPA tissue IHC). Score the relevant cells and liver region; a negative result in a different population does not contradict those observations (HPA tissue IHC). |
| Subcellular distribution and topology | GLUL is mainly cytosolic, with a membrane-associated fraction and no transmembrane segment (UniProt P15104). A fine cytoplasmic pattern fits this record; membrane-associated signal may coexist, but a membrane-only IHC result needs scrutiny (UniProt P15104; general IHC practice). |
| Strength of validation evidence | The tissue profile is Approved despite medium staining–RNA consistency, and paired antibodies support its expression profile (HPA tissue IHC). Three listed antibodies have Approved IHC status; this supports comparison with the HPA pattern but does not prove that every deposit is specific (HPA antibodies; general IHC practice). |
| IF/ICC Q: What should fluorescence show? | A: HPA reports approved cytosol and mitochondria as main locations, with plasma membrane and connecting piece as additional locations (HPA subcellular). These ICC-IF observations provide a localization cross-check; assess paraffin-section chromogenic results against the tissue IHC pattern (HPA tissue IHC; HPA subcellular). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected positive cells have no chromogenic signal. | The run may have failed, or the sampled section may lack the expected cell population (general IHC practice). | Confirm cell identity and an on-slide or parallel positive control; review the catalog antibody’s validated IHC-P conditions and detection controls (general IHC practice). |
| Signal appears chiefly in nuclei. | That compartment conflicts with the reported mainly cytosolic localization (UniProt P15104; HPA subcellular). | Check the primary-antibody omission control and inspect whether precipitate or counterstain is being mistaken for target signal (general IHC practice). |
| Most cells stain equally despite distinct expected populations. | Uniform color may reflect nonspecific staining rather than the reported cell-selective profile (HPA tissue IHC; general IHC practice). | Compare expected and reported-negative cell populations; review blocking, antibody concentration, washes, and detection-control staining (HPA tissue IHC; general IHC practice). |
| Color remains when the primary antibody is omitted. | The signal can arise from detection chemistry or endogenous activity rather than antibody-bound GLUL (general IHC practice). | Check the chromogenic detection controls and apply the assay’s appropriate endogenous-activity blocking step (general IHC practice). |
| A reported-negative population stains strongly. | Cross-reactivity or endogenous detection activity is possible; HPA calls specific populations Not detected, including cardiomyocytes and glomerular cells (HPA tissue IHC; general IHC practice). | Verify the scored cell type, inspect the no-primary control, and compare a documented positive population in the same run (HPA tissue IHC; general IHC practice). |
| Cytoplasmic staining is patchy across adjacent sections. | Differences in sampled cells or staining-run consistency may affect the comparison (general IHC practice). | Compare matching tissue regions and cell types first; then review section quality and the validated IHC-P workflow across runs (general IHC practice). |
Experiment evidence
IHC & IF images showing GLUL staining
A03191-3 · IHCIHC analysis of GLUL using anti-GLUL antibody (A03191-3). GLUL was detected in a paraffin-embedded section of human appendiceal adenocarcino
A03191-3 · IHCIHC analysis of GLUL using anti-GLUL antibody (A03191-3). GLUL was detected in a paraffin-embedded section of human gastric adenocarcinoma t
A03191-3 · IFIF analysis of GLUL using anti-GLUL antibody (A03191-3). GLUL was detected in an immunocytochemical section of A431 cells. Enzyme antigen re
M03191 · IHCImmunohistochemical analysis of paraffin-embedded Human glioblastoma, using the Antibody at 1:250 dilution.
M03191 · IHCImmunohistochemical analysis of paraffin-embedded Human prostate cancer, using the Antibody at 1:250 dilution.
M03191 · IFImmunofluorescent analysis using the Antibody at 1:50 dilution.
M03191-2 · IHCRat liver was stained with anti-Glutamine Synthetase rabbit antibody
M03191-2 · IHCHuman hepatocellular carcinoma was stained with anti-Glutamine Synthetase rabbit antibody
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000135821-GLUL/tissue/cerebral+cortex#imid_2256216
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000135821-GLUL/tissue/colon#imid_2256142
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000135821-GLUL/tissue/liver#imid_2256143
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000135821-GLUL/tissue/kidney#imid_2256152
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB008636; green = GLUL, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB008636; green = GLUL, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for GLUL IHC & IF
🧪Run cerebral cortex first and expect staining in glial cells (HPA: High in cerebral-cortex glial cells). Use heart muscle cardiomyocytes as the negative comparison (HPA: Not detected in cardiomyocytes); on the cortex slide, neighboring neuronal somata should remain near background and serve as candidate internal negatives, checked against the no-primary control (standard IHC practice).
Positive control tissue: Adipose tissue (Adipocytes, HPA High)
Negative control tissue: Adrenal gland (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show GLUL in A-431, U-251MG, U2OS, Sperm, with annotated localisation: Mitochondria (approved), Cytosol (approved) (HPA subcellular).
Technical controls: Include no-primary (secondary-only) and isotype controls, using rabbit IgG matched to the catalog primary’s clonality and preparation, plus a matched GLUL-knockout specimen as a biological negative (caption: rabbit anti-GLUL primary; standard IHC practice). For cerebral cortex, block endogenous peroxidase and check endogenous biotin before interpreting SABC/DAB signal (caption: SABC/DAB detection; standard IHC practice).
⚠️Feasibility: The selected A03191-3 paraffin-section caption does not report a fixative, and the supplied evidence reports no target-specific fixation window or fixation effect (caption: fixative unreported). Heat retrieval in EDTA at pH 8.0 is documented, but whether GLUL staining depends on that retrieval condition is unreported; the evidence also does not establish that frozen sections or IF are easier (caption: heat retrieval in EDTA, pH 8.0). In cerebral cortex, endogenous pigment can complicate chromogenic interpretation, so compare cellular signal with the negative controls (standard IHC practice).
HPA tissue IHC evidence for GLUL
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Medium consistency between antibody staining and RNA expression data. Paired antibodies with high similarity supports the protein expression profile.). 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 |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | High | Protein (IHC) | HPA → |
| Caudate | Glial cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Glial cells | High | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | High | Protein (IHC) | HPA → |
| Hippocampus | Glial cells | High | 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 → |
| Endometrium | Cells in endometrial stroma | Not detected | Protein (IHC) | HPA → |
| Heart muscle | Cardiomyocytes | Not detected | Protein (IHC) | HPA → |
| Kidney | Cells in glomeruli | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced GLUL IHC Tips
Troubleshoot GLUL staining in paraffin sections by checking retrieval, cellular localisation, tissue context and detection controls.
Which antigen retrieval should I try first for weak GLUL staining?
Start with heat mediated retrieval in EDTA at pH 8.0 for this catalog antibody (datasheet A03191-3). The documented paraffin section workflow then used 10% goat serum, 2 μg/ml primary antibody overnight at 4°C, and biotinylated secondary antibody for 30 minutes at 37°C (datasheet A03191-3). If signal remains weak, compare retrieval heating and cooling conditions while keeping section thickness, antibody incubation and detection constant (standard IHC practice). Include a known positive cell population on the same run so that a retrieval failure can be distinguished from genuinely low GLUL expression in the test region (HPA: high in glial cells; standard IHC practice).
Could fixation explain weak or patchy GLUL staining?
The selected paraffin section caption does not report a fixative, so target specific GLUL sensitivity to fixation is unknown (datasheet A03191-3). Record the specimen’s actual fixative and fixation interval, then compare sections processed under matched conditions before attributing staining differences to biology (standard IHC practice). For this antibody, keep the documented EDTA retrieval at pH 8.0 and 2 μg/ml primary incubation constant during that comparison (datasheet A03191-3). UniProt reports cytosolic localisation and modified residues, but neither establishes a fixation effect or an optimal fixation time for this antibody (UniProt P15104 localisation and modified residues).
Where should GLUL staining appear in a convincing section?
Expect predominantly cytoplasmic staining, assessed in identifiable cells rather than across an undifferentiated tissue field (HPA: cytoplasmic expression in several cell types; standard IHC practice). GLUL mainly localises to the cytosol, with a fraction associated with the cell membrane, and has no transmembrane segment (UniProt P15104 localisation and topology). Mitochondrial and plasma membrane localisation are also reported, so a minor noncytosolic component should be judged against cell morphology and controls (HPA: approved subcellular locations). In liver, compare the distribution around the central vein, where hepatocyte staining is distinct, while checking that diffuse extracellular chromogen is not being counted as cellular signal (HPA: hepatocytes around the central vein; standard IHC practice).
Can an isoform or modified epitope explain discordant staining?
The supplied record lists 0 alternative isoforms, so an isoform switch is not an evidenced explanation for discordant IHC staining (UniProt P15104 isoforms). It places a beta grasp region at residues 24–106 and a catalytic region at 113–373, but the antibody epitope is not specified here (UniProt P15104 domains; datasheet A03191-3). Acetylated residues and phosphorylation sites are annotated, yet their effect on this antibody’s binding in sections is unknown (UniProt P15104 modified residues). If staining differs between preparations, compare retrieval and antibody controls first; interpreting a particular modification as epitope masking would require epitope mapping or direct validation (standard IHC practice).
How should I cross-check an IHC pattern with multiplex IF?
Use IF as a separate validation experiment and pair GLUL with a marker for the expected cell type, such as a glial cell marker when examining the reported glial pattern (HPA: high in glial cells; standard IF practice). Choose fluorophores and control channels after measuring tissue autofluorescence, especially where broad background could mimic cytoplasmic signal (standard IF practice). Because GLUL is mainly cytosolic and has no transmembrane segment, assess permeabilisation for access to an intracellular epitope; the epitope’s exact position is unspecified (UniProt P15104 localisation and topology; datasheet A03191-3; standard IF practice). Compare compartment and cell identity with chromogenic IHC, without assuming its pH 8.0 retrieval conditions transfer to IF (datasheet A03191-3; standard IF practice).
How can I reduce diffuse or misleading DAB background?
First inspect no primary and secondary only controls to separate nonspecific detection from GLUL dependent staining (standard IHC practice). The documented workflow uses a biotinylated secondary, streptavidin biotin complex and DAB, so evaluate endogenous biotin and peroxidase activity with appropriate controls and a peroxidase block (datasheet A03191-3; standard IHC practice). Check whether the documented 10% goat serum block and 2 μg/ml primary concentration give adequate contrast in your tissue (datasheet A03191-3). Optimise washes and DAB development using matched sections, then judge residual colour against expected cytoplasmic staining rather than accepting uniform staining across every compartment (HPA: cytoplasmic profile; standard IHC practice).
What is a defensible way to quantify heterogeneous GLUL IHC? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and anatomical region before scoring, since GLUL expression varies by cell type and shows a distinct distribution in hepatocytes around the central vein (HPA: tissue IHC profile). Report an H-score or the percentage of positive cells with prespecified intensity thresholds, and retain separate scores for relevant cell populations (standard IHC practice). Normalise positive counts to the total number of evaluable cells in that population; for area based density, state the measured tissue area in mm² (standard IHC practice). Use matched staining runs and exclude folds, necrosis and edge artefacts consistently so that technical variation does not become an apparent expression difference (standard IHC practice).
When should an apparent GLUL positive region be questioned?
A credible signal should occupy identifiable cell cytoplasm and fit the sampled cell population; HPA reports high staining in adipocytes and glial cells but no detection in normal appendix glandular cells (HPA: tissue IHC profile). The catalog image documents staining in a human appendiceal adenocarcinoma section, which does not establish expression in normal appendix glands (datasheet A03191-3; HPA: appendix glandular cells not detected). Question staining confined to cut edges, necrotic areas or empty spaces, and compare it with no primary controls (standard IHC practice). If DAB persists without primary antibody, investigate endogenous peroxidase or detection background before assigning that colour to GLUL (standard IHC practice).
Boster reagents
Best GLUL / Glutamine synthetase IHC Antibodies
Catalog anti-GLUL antibodies have IHC images from human tumors and rat and mouse tissues; an IF image documents A431 cells (catalog image captions).
Real IHC data
Anti-GLUL Antibody ®
Cat # A03191-3
Real IHC data
Anti-Glutamine Synthetase GLUL Rabbit Monoclonal Antibody
Cat # M03191
Real IHC data
Anti-Glutamine Synthetase Rabbit Monoclonal Antibody
Cat # M03191-2
A03191-3 has paraffin-section IHC images from human appendiceal, gastric, liver and lung cancers, plus IF data from A431 cells (catalog image captions). M03191 has paraffin-section IHC images from human glioblastoma and prostate cancer, rat kidney and mouse ovary; M03191-2 has IHC images from rat and mouse liver and human hepatocellular carcinoma (catalog image captions).
Which to pick: For tissue IHC, A03191-3 provides a documented paraffin-section workflow using EDTA retrieval and 2 μg/ml primary antibody (A03191-3 IHC caption); the fixative is unreported (A03191-3 IHC caption). For IF/ICC, choose A03191-3, which lists both applications and has an A431 cell IF image (A03191-3 applications and IF caption). For cross-species tissue IHC, consider M03191-2: it is a rabbit monoclonal reactive with human, mouse and rat, with IHC images from all three species (M03191-2 catalog and IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P15104 (GLNA_HUMAN, Glutamine synthetase).
- Human Protein Atlas. GLUL tissue IHC expression (reliability: Approved).
- Human Protein Atlas. GLUL subcellular location (ICC-IF): Mainly localized to the cytosol and mitochondria. In addition localized to the plasma membrane and connecting piece..
- Human Protein Atlas. GLUL antibody validation summary (3 antibodies).
- Well-differentiated liver cancers reveal the potential link between ACE2 dysfunction and metabolic breakdown. Scientific reports 2022 — PMC8814043.
- Aberrant expression and distribution of enzymes of the urea cycle and other ammonia metabolizing pathways in dogs with congenital portosystemic shunts. PloS one 2014 — PMC4063766.
- A simple, rapid fluorescent reporter-based method for detection of ectopic cre recombinase expression in presumed retinal cell type-targeted mouse lines. Experimental eye research 2023 — PMC10756212.
- Glutamine Anabolism Plays a Critical Role in Pancreatic Cancer by Coupling Carbon and Nitrogen Metabolism. Cell reports 2019 — PMC6886125.
- PubMed PMID:2888076 — UniProt-cited evidence.
- PubMed PMID:1681907 — UniProt-cited evidence.
- PubMed PMID:7909780 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for GLUL (Glutamine synthetase). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A03191-3). Validated IHC antibody: A03191-3 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adipose tissue (Adipocytes); negative Adrenal gland. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human appendiceal adenocarcinoma tissue; fixative not specified (datasheet A03191-3); 2. Fixation: Image fixative and duration unreported (datasheet A03191-3); 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 A03191-3); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A03191-3); 8. Primary antibody: Rabbit anti-GLUL, 2-5 μg/ml (datasheet A03191-3); 9. Primary incubation: Overnight at 4 °C (datasheet A03191-3). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A03191-3); Caveat: Pericentral hepatocyte enrichment can skew liver scoring (HPA tissue IHC); Isoform / epitope: No annotated isoforms, signal peptide or propeptide (UniProt); Regulation: Cell type and liver zone specific (HPA tissue IHC). Evidence: UniProt P15104, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the cytosol and mitochondria. In addition…, Datasheet A03191-3, PMC6886125. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/GLUL/immunohistochemistry-ihc-guide.