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GLUL / Glutamine synthetase · IHC design guide
Design Immunohistochemistry for GLUL
Plan paraffin-section GLUL IHC around its cytoplasmic staining in adipocytes, glia, macrophages and pericentral hepatocytes (HPA tissue IHC). This guide covers fixation, staining controls and scoring across tissue regions (standard IHC practice).
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 staining in tissue (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic in adipocytes, glia, macrophages and pericentral hepatocytes (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 | Keep fixation consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Pericentral hepatocyte staining can make liver scoring region-dependent (HPA tissue IHC) | |
| Regulation | Expression varies by cell type (HPA tissue IHC) | |
| Isoform / epitope | No annotated isoforms; mature chain begins at residue 2 (UniProt) |
Section 1
Recommended GLUL IHC & IF Protocols
The catalog antibody’s IHC-P protocol is supplemented by published GLUL staining methods for human liver and pancreas sections (PMC8814043; 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 pH 8.0 retrieval for the catalog antibody (datasheet A03191-3); citrate pH 6.0 is a published alternative for pancreas IHC (PMC6886125).
Section 2
What Is the Expected GLUL Staining Pattern?
Expect predominantly cytoplasmic GLUL staining in adipocytes, glial cells, macrophages, and hepatocytes around the central vein (HPA: tissue IHC). GLUL mainly resides in the cytosol, although a fraction associates with the cell membrane; it has no transmembrane segment (UniProt P15104: localization and topology). HPA rates the tissue profile Approved, with medium consistency between antibody staining and RNA expression (HPA: tissue IHC reliability).
| Distinct cytoplasmic staining in adipocytes or glial cells. | This fits the reported pattern; HPA grades adipocytes and glial cells in caudate, cerebral cortex, and hippocampus High (HPA: tissue IHC). Compare cells within the section: an expected compartment and cell type together make a stronger interpretation than stain intensity alone (general IHC practice). |
| Strong staining confined to nuclei, with little cytoplasmic signal. | Predominantly nuclear staining conflicts with GLUL's mainly cytosolic localization (UniProt P15104: localization; HPA: subcellular). Check antibody and detection controls before calling it GLUL; a membrane-associated fraction can occur, so limited peripheral staining alone is not a wrong-compartment result (UniProt P15104: localization). |
| Prominent staining in a cell population HPA lists as not detected. | For example, HPA reports Not detected in lymph-node germinal-center cells and kidney glomerular cells; that finding does not describe every cell in either tissue (HPA: tissue IHC). Verify the cell identity and inspect controls for cross-reactivity or endogenous detection activity before assigning target expression (general IHC practice). |
| Weak, diffuse color covers cells and surrounding tissue. | This is difficult to score as GLUL when cytoplasmic cell boundaries are obscured (HPA: tissue IHC profile; general IHC practice). Compare a no-primary control, inspect endogenous detection activity, and assess blocking, washing, and chromogen development as general IHC workflow checks (general IHC practice). |
| No signal in adipocytes or glial cells expected to stain strongly. | An absent signal in these known-positive cell populations argues for a technical check before a biological absence call (HPA: High in adipocytes and glial cells). Verify that the relevant cells are present, then review antibody use, detection reagents, retrieval, and slide quality (general IHC practice). |
💡Expected GLUL appearanceCall a convincing positive when distinct, predominantly cytoplasmic signal appears in expected cells, especially High-staining adipocytes or glial cells; uniform haze or isolated nuclear color is suspect (HPA: tissue IHC; UniProt P15104: localization; general IHC practice).
| Cell and tissue context | HPA reports High staining in adipocytes, glial cells, placental trophoblasts, testicular Leydig cells, and bladder urothelial cells; it also describes hepatocytes around the central vein (HPA: tissue IHC). Judge the identified cell population, since HPA's not-detected entries are cell-specific rather than whole-organ negatives (HPA: tissue IHC). |
| Compartment and topology | GLUL is mainly cytosolic, with a membrane-associated fraction and no transmembrane segment (UniProt P15104: localization and topology). HPA also approves cytosol and mitochondria as main ICC-IF locations (HPA: subcellular). Thus, predominantly cytoplasmic IHC staining fits the evidence; avoid requiring a crisp membrane outline (UniProt P15104: localization). |
| Interpretive confidence | HPA's tissue profile is Approved but has medium staining-versus-RNA consistency; paired antibodies show high similarity (HPA: tissue IHC reliability). Its listed antibodies HPA007316, HPA007571, and CAB008636 each have Approved IHC status (HPA: antibodies). Treat this as support for the reported pattern, while checking unusual results against controls (general IHC practice). |
| Antigen retrieval | Use the validated IHC-P conditions for the chosen antibody when available, and optimize retrieval with a known-positive control if needed (general IHC practice). The supplied UniProt and HPA records give no GLUL-specific retrieval condition or fixation-sensitivity result; neither tissue staining nor topology establishes one (UniProt P15104; HPA: tissue IHC). |
| IF/ICC: what localization should I expect? | HPA approves cytosol and mitochondria as main ICC-IF locations, with plasma membrane and connecting piece as additional locations (HPA: subcellular). UniProt describes mainly cytosolic GLUL with a membrane-associated fraction (UniProt P15104: localization). Use the separate IF/ICC guide for that application. |
| Situation | Likely cause | Next action |
|---|---|---|
| Positive control shows no staining. | The expected cells may be absent from the section, or an IHC workflow step may have failed (HPA: tissue IHC; general IHC practice). | Confirm adipocytes or glial cells are present; then check antibody use, retrieval, detection reagents, and slide quality with the chosen antibody's IHC-P instructions (HPA: High in those cells; general IHC practice). |
| Signal is mainly nuclear. | That distribution conflicts with the reported predominantly cytoplasmic pattern (HPA: tissue IHC; UniProt P15104: localization). | Review counterstain and no-primary controls, confirm which color is chromogen, and reassess whether cytoplasmic signal is present (general IHC practice). Do not score nuclear color alone as convincing GLUL. |
| Many unrelated cell types stain uniformly. | Diffuse binding or endogenous detection activity can obscure the cell-specific pattern (general IHC practice; HPA: tissue IHC profile). | Check a no-primary control and the detection system; review blocking, washing, and chromogen development (general IHC practice). Compare the result with expected cytoplasmic staining in identified cells (HPA: tissue IHC). |
| A supposed negative tissue contains positive cells. | HPA's negative labels apply to named cells, such as glomerular cells in kidney, not necessarily to every cell in that organ (HPA: tissue IHC). | Identify the stained population before calling the control failed. Compare like cells across sections, and use a no-primary control if the staining remains unexpected (HPA: tissue IHC; general IHC practice). |
| Peripheral staining appears alongside cytoplasmic signal. | A fraction of GLUL can associate with the cell membrane, despite lacking a transmembrane segment (UniProt P15104: localization and topology). | Assess whether cytoplasmic staining remains the dominant pattern and whether the stained cells fit HPA tissue observations (UniProt P15104: localization; HPA: tissue IHC). Check detection controls if the peripheral signal is widespread (general IHC practice). |
| Positive cells stain much less than expected. | Apparent intensity depends on both the sampled cell population and assay performance; HPA levels describe observed cells, not a guaranteed intensity in every run (HPA: tissue IHC; general IHC practice). | Verify cell identity against HPA's named populations, compare an appropriate positive control, and review the chosen antibody's IHC-P instructions and detection development (HPA: tissue IHC; 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 (High; HPA: cerebral cortex glial cells). Use heart muscle cardiomyocytes as the negative tissue (Not detected; HPA: heart muscle cardiomyocytes); cells without visible staining on the cortex slide can indicate background, but HPA does not identify an internal GLUL-negative cell population there.
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), concentration-matched rabbit IgG isotype, and GLUL knockout tissue or cells as a biological negative (caption: rabbit primary; standard IHC practice). In cortex, assess endogenous peroxidase and tissue pigment before interpreting brown DAB signal, and check endogenous biotin if using the caption’s biotin-based detection system (caption: SABC with DAB; standard IHC practice).
⚠️Feasibility: The target-specific fixation window and fixation effect are unreported; the selected A03191-3 paraffin-section caption does not state a fixative (caption: fixative unreported). That caption uses heat-mediated EDTA retrieval at pH 8.0, but does not establish that retrieval is required (caption: EDTA retrieval). The supplied evidence does not establish whether frozen sections or IF are easier; cortex pigment can complicate chromogenic scoring (HPA: cerebral cortex glial cells; 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 chromogenic IHC in paraffin sections by checking retrieval, staining controls, compartment, cell identity, and scoring against documented expression patterns.
Which retrieval condition should I start with for GLUL in paraffin sections?
Start with heat-mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet A03191-3). The documented tissue image used that condition, followed by 2 μg/mL primary antibody overnight at 4°C (caption A03191-3). If staining is weak, compare serial sections while changing heat exposure one step at a time; record the heating and cooling conditions because the caption does not specify them (caption A03191-3; standard IHC practice). Check whether signal improves in expected GLUL-positive cells without staining blank areas or damaging tissue morphology (HPA: high in adipocytes and glial cells; standard IHC practice).
Could fixation explain weak or inconsistent GLUL staining?
Target-specific fixation sensitivity is unknown because the selected paraffin-section caption does not state a fixative or fixation interval (caption A03191-3). Record the fixative, time before fixation, and fixation duration for each specimen, then compare sections processed together under the same EDTA pH 8.0 retrieval condition (datasheet A03191-3; standard IHC practice). If signal differs between batches, examine morphology and control tissue before attributing the difference to GLUL abundance (standard IHC practice). Keep the documented 2 μg/mL primary concentration constant during that comparison so changes in antibody dose do not obscure a processing effect (caption A03191-3; standard IHC practice).
What staining pattern and compartment should I expect for GLUL?
Expect predominantly cytoplasmic staining: GLUL mainly localizes to the cytosol, with a fraction associated with the cell membrane (UniProt P15104), and tissue IHC reports cytoplasmic expression across several cell types (HPA: tissue IHC profile). GLUL has no transmembrane segment, so a sharp membrane-only outline needs independent validation before being called the expected pattern (UniProt P15104 topology; standard IHC practice). Assess the stained cell population as well as its compartment; HPA reports high signal in adipocytes and glial cells and distinct hepatocyte staining around the central vein (HPA: tissue IHC profile). Chromogenic sections alone may not resolve a mitochondrial fraction that has been observed by IF (HPA: approved subcellular locations; standard microscopy practice).
How should I troubleshoot an unexpected GLUL epitope-dependent pattern?
The supplied record lists 0 alternative isoforms and identifies the mature chain as residues 2–373 (UniProt P15104). It places a beta-grasp domain at residues 24–106 and a catalytic domain at 113–373, but the antibody's binding site is not provided here (UniProt P15104; supplied antibody evidence). Acetylated residues and phosphorylation sites are recorded, yet their effect on this antibody's staining is untested in the supplied evidence (UniProt P15104; supplied antibody evidence). If a pattern changes after retrieval, compare matched sections and seek an independent GLUL-specific control before assigning the change to an isoform or modification (standard IHC validation practice).
How can I check GLUL localisation by multiplex immunofluorescence?
Pair GLUL with a validated marker for the expected cell population, such as glial cells in brain material, and inspect colocalisation at the single-cell level (HPA: high in glial cells; standard IF practice). Choose spectrally separated fluorophores and consider a red or far-red GLUL channel where tissue autofluorescence compromises shorter wavelengths (standard IF practice). Permeabilise appropriately for intracellular epitopes: GLUL is mainly cytosolic and also has approved mitochondrial localisation, while its membrane-associated fraction has no transmembrane segment (UniProt P15104 topology; HPA: subcellular locations). Optimise IF fixation and permeabilisation independently; the supplied IHC caption reports no fixative and supplies no IF fixation condition (caption A03191-3).
What should I check when GLUL IHC has diffuse background?
Compare a no-primary control with the stained section to identify signal arising from the detection system (standard IHC practice). The documented image used 10% goat serum, a biotinylated secondary antibody, a streptavidin–biotin complex, and DAB (caption A03191-3). For that chromogenic workflow, verify peroxidase blocking and assess endogenous biotin if background persists; these are general detection controls, not evidence of a GLUL-specific problem (standard IHC practice). Titrate primary antibody around the documented 2 μg/mL condition and inspect whether background falls while expected cytoplasmic staining remains in the relevant cells (caption A03191-3; HPA: tissue IHC profile; standard IHC practice).
How should I score GLUL staining across heterogeneous sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and viable tissue region before scoring, because GLUL expression differs by cell type and hepatocyte position around the central vein (HPA: tissue IHC profile; standard IHC practice). Record the percentage of positive cells and staining intensity separately, or calculate an H-score from intensity categories 0–3 and their cell percentages, yielding 0–300 (standard IHC scoring practice). Normalise positive-cell counts to the number of eligible cells, or stained area to viable tissue area in mm², using the same denominator across samples (standard IHC practice). Keep retrieval, detection, imaging, and scoring thresholds consistent, and report cell-specific results rather than a whole-section average alone (standard IHC practice).
How do I distinguish genuine GLUL staining from artefact?
Give greatest weight to cytoplasmic staining in plausible cells, such as adipocytes or glial cells, while checking the tissue context and morphology (HPA: tissue IHC profile; standard IHC practice). A membrane-only outline warrants further validation because GLUL mainly localizes to the cytosol and lacks a transmembrane segment (UniProt P15104). Treat staining confined to cut edges or necrotic regions cautiously, and compare it with intact areas on the same section (standard IHC practice). If DAB appears in the no-primary control, investigate endogenous peroxidase or the biotin-based detection system before assigning it to GLUL (caption A03191-3; standard IHC practice).
Boster reagents
Best GLUL / Glutamine synthetase IHC Antibodies
Anti-GLUL antibodies have IHC images from human, mouse and rat tissues (catalog IHC image captions), with an IF/ICC image from A431 cells (A03191-3 IF image caption).
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 IHC images from human appendiceal, gastric, liver and lung tumors (A03191-3 IHC image captions); M03191 has paraffin-section images from human glioblastoma and prostate cancer, rat kidney and mouse ovary (M03191 IHC image captions). M03191-2 has IHC images from rat and mouse liver and human hepatocellular carcinoma (M03191-2 IHC image captions).
Which to pick: For paraffin-section IHC, choose A03191-3 if its documented EDTA retrieval at pH 8.0 and 2 μg/ml staining example suit your tissue; the fixative is unreported (A03191-3 IHC image caption). For IF/ICC, choose A03191-3: its A431 cell image documents 5 μg/ml primary antibody and a fluorescent secondary (A03191-3 IF image caption). For IHC across human, mouse and rat, consider the rabbit monoclonal M03191-2, which has an IHC application listing and images from all three species; its image captions do not report section processing or fixative (M03191-2 catalog applications, title and IHC image 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 staining in tissue (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: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Pericentral hepatocyte staining can make liver scoring region-dependent (HPA tissue IHC); Isoform / epitope: No annotated isoforms; mature chain begins at residue 2 (UniProt); Regulation: Expression varies by cell type (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, PMC8814043, PMC6886125. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/GLUL/immunohistochemistry-ihc-guide.