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GSTK1 / Glutathione S-transferase kappa 1 · IHC design guide
Design Immunohistochemistry for GSTK1
Plan GSTK1 paraffin IHC around granular cytoplasmic tissue staining (HPA tissue IHC). This guide covers the catalog antibody’s 1:50 starting dilution and tissue comparisons, including smooth muscle cells with no detected staining (datasheet: M06112-1; HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
GSTK1 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 | Granular cytoplasm (HPA tissue IHC); peroxisome (UniProt) | |
| Staining pattern | Granular cytoplasm across diverse cell types (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet M06112-1) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Smooth muscle |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Smooth muscle cells have no detected staining (HPA tissue IHC) | |
| Regulation | No specific expression regulator reported (UniProt) | |
| Isoform / epitope | 4 isoforms; epitope coverage is unknown (UniProt) |
Section 1
Recommended GSTK1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet M06112-1) and a published GSTK1 protocol for head and neck squamous cell carcinoma tissues (PMC10020208) provide chromogenic IHC starting points.
| Sample | Paraffin-embedded human breast cancer tissue; fixative not specified (datasheet M06112-1) |
| Fixation | Image fixative and duration unreported (datasheet M06112-1); 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 M06112-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet M06112-1) |
| Primary antibody | Rabbit monoclonal (clone 21G63) anti-GSTK1, 1:50 (datasheet M06112-1) |
| Primary incubation | Overnight at 4 °C (datasheet M06112-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet M06112-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | GSTK1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Ubiquitous granular cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet M06112-1). The published protocol does not specify retrieval (PMC10020208).
Section 2
What Is the Expected GSTK1 Staining Pattern?
GSTK1 should appear as granular cytoplasmic staining consistent with peroxisomes, rather than a nuclear or membrane pattern (HPA tissue IHC; HPA ICC-IF; UniProt Q9Y2Q3 topology). Expression is widespread, with high staining reported in adrenal glandular cells, bronchial respiratory epithelium, and cortical glia (HPA tissue IHC). Treat the pattern as a supported expectation, not a definitive diagnostic rule: HPA reports medium agreement between staining and RNA data, pending external verification (HPA tissue IHC).
| Granular cytoplasmic signal in adrenal glandular cells or bronchial respiratory epithelial cells. | This fits the reported high staining in these cells and the peroxisomal location (HPA tissue IHC; HPA ICC-IF). Judge granularity and cell identity alongside intensity; nearby cells need not stain equally. |
| Predominantly nuclear, crisp plasma-membrane, or extracellular staining. | These compartments do not match the supported peroxisomal pattern (HPA ICC-IF; UniProt Q9Y2Q3 topology). Check whether the signal persists in a detection-only control before interpreting it as GSTK1. |
| Strong staining assigned to smooth muscle cells. | HPA reports GSTK1 as not detected in smooth muscle cells (HPA tissue IHC). Recheck cell identification and compare a primary-antibody omission control; cross-reactivity or endogenous detection activity may explain discordant staining. |
| Uniform chromogen haze across cells and extracellular areas. | A field-wide haze obscures the granular cytoplasmic pattern reported by HPA (HPA tissue IHC). In general IHC practice, review blocking, washes, antibody concentration, and the detection-only control before scoring cells. |
| No visible signal in an adequately preserved section of adrenal gland or bronchus. | Absence conflicts with the reported high staining in the specified cells (HPA tissue IHC). Check that those cells are present, then review the catalog antibody's IHC-P conditions and detection controls; one blank section does not establish absent GSTK1. |
💡Expected GSTK1 appearanceCall a section positive when identified HPA high-staining cells show clear, granular cytoplasmic chromogen (HPA tissue IHC); dominant nuclear, membrane, or field-wide staining is discordant with the supported peroxisomal location (HPA ICC-IF; UniProt Q9Y2Q3 topology).
| Tissue and cell selection | GSTK1 is ubiquitous by UniProt, while HPA reports high, low, and undetected staining in different cell types (UniProt Q9Y2Q3; HPA tissue IHC). Select and score the named cells, rather than assigning one intensity to an entire tissue. |
| Pattern confidence | The tissue pattern is Supported, with medium agreement between antibody staining and RNA and external verification pending (HPA tissue IHC). Use the reported pattern as a reference and interpret unexpected results with controls. |
| Antibody evidence | HPA006311 and HPA022904 each have Supported IHC status; HPA022904 also has Supported ICC status (HPA antibodies). These ratings support the stated applications, but do not validate an unlisted reagent or dilution. |
| Compartment and topology | UniProt places GSTK1 in peroxisomes and annotates no transmembrane segment; HPA ICC-IF also supports peroxisomes (UniProt Q9Y2Q3 topology; HPA ICC-IF). Expect intracellular granules, without claiming that each chromogenic punctum identifies one organelle. |
| Isoforms and processing | UniProt lists four isoforms, one annotated chain spanning residues 1–226, and no signal peptide or propeptide (UniProt Q9Y2Q3). The payload gives no antibody epitope, so it cannot establish which isoforms the IHC reagent detects. |
| What should IF/ICC show? | Peroxisomal localization is supported, with ICC-IF images listed for A-431, U-251MG, and U2OS (HPA ICC-IF). That is a localization cross-check; this IHC section does not supply an IF/ICC protocol. |
| Situation | Likely cause | Next action |
|---|---|---|
| No staining in adrenal glandular cells or bronchial respiratory epithelium. | These cells are reported High (HPA tissue IHC); the missing signal could reflect cell selection or an IHC workflow failure, rather than proven absence of GSTK1. | Confirm the named cells on the section. Review the catalog antibody's IHC-P instructions, including its specified retrieval and dilution, then check detection reagents with an appropriate positive control (general IHC practice). |
| Only weak signal in a tissue expected to be high. | HPA levels describe particular cells, and its tissue pattern has medium staining–RNA agreement (HPA tissue IHC). Whole-section scoring may dilute a focal high-cell result. | Score the reported cell population directly and compare it with a known high-staining cell population on a comparable section (HPA tissue IHC); review routine IHC controls before changing conditions. |
| Smooth muscle appears strongly positive. | That cell type is reported Not detected (HPA tissue IHC); mistaken cell assignment, cross-reactivity, or endogenous chromogenic activity are possible. | Verify morphology and compare primary-antibody omission and detection-only controls (general IHC practice). Treat a persistent granular signal as discordant with HPA, rather than automatically declaring it false. |
| Nuclei or cell borders dominate the image. | Dominant nuclear or membrane staining conflicts with the supported peroxisomal location and absence of a transmembrane segment (HPA ICC-IF; UniProt Q9Y2Q3 topology). | Check the counterstain and chromogen separately, then inspect a detection-only control and a reported high-staining cell population (general IHC practice; HPA tissue IHC). |
| Diffuse brown background prevents cell-level scoring. | Field-wide signal can arise from nonspecific binding or endogenous detection activity in chromogenic IHC (general IHC practice); it does not establish GSTK1 distribution. | Review blocking, washes, antibody dilution, and the detection-only control under the chosen IHC detection system (general IHC practice). Score only when cellular granules are distinguishable. |
| A low-staining cell type looks as strong as a reported high-staining type. | HPA reports low staining in oral squamous epithelium and high staining in adrenal glandular cells, with medium overall staining–RNA agreement (HPA tissue IHC). | Compare the identified cell types under the same scoring criteria, inspect background controls, and record the discrepancy (general IHC practice; HPA tissue IHC). Do not infer a GSTK1-specific fixation effect from it. |
Experiment evidence
IHC & IF images showing GSTK1 staining
M06112-1 · IHCIHC analysis of GSTK1 using anti-GSTK1 antibody (M06112-1). GSTK1 was detected in a paraffin-embedded section of human breast cancer tissue.
M06112-1 · IHCIHC analysis of GSTK1 using anti-GSTK1 antibody (M06112-1). GSTK1 was detected in a paraffin-embedded section of human prostate cancer tissu
A06112-3 · IHCIHC analysis of GSTK1 using anti-GSTK1 antibody (A06112-3). GSTK1 was detected in a paraffin-embedded section of human breast cancer tissue.
A06112-3 · IHCIHC analysis of GSTK1 using anti-GSTK1 antibody (A06112-3). GSTK1 was detected in a paraffin-embedded section of mouse heart tissue. Heat me
A06112-3 · IFIF analysis of GSTK1 using anti-GSTK1 antibody (A06112-3). GSTK1 was detected in a paraffin-embedded section of human breast cancer tissue.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000197448-GSTK1/tissue/cerebral+cortex#imid_2017352
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000197448-GSTK1/tissue/colon#imid_2017270
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000197448-GSTK1/tissue/liver#imid_2017271
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000197448-GSTK1/tissue/kidney#imid_2017272
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA022904; green = GSTK1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA022904; green = GSTK1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for GSTK1 IHC & IF
🧪Run bronchus first: respiratory epithelial cells should stain strongly (HPA: High in bronchus respiratory epithelial cells). Run smooth muscle as the negative tissue (HPA: Not detected in smooth muscle cells); smooth muscle cells within the bronchus section should show background-only staining as an internal comparator (HPA: Not detected in smooth muscle cells).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: Smooth muscle (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show GSTK1 in A-431, U-251MG, U2OS, with annotated localisation: Peroxisomes (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; a concentration-matched rabbit isotype control (selected M06112-1 caption: rabbit primary); and GSTK1-knockout material as a biological negative. Quench endogenous peroxidase and check background in the bronchus section before interpreting DAB staining (standard chromogenic IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the fixative is unreported in the selected M06112-1 tissue-IHC caption. That paraffin-section example uses heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required (selected M06112-1 caption). Frozen sections or IF/ICC cannot be judged easier from the supplied evidence; bronchus background requires attention to endogenous peroxidase in chromogenic IHC and autofluorescence if IF is used (standard IHC/IF practice).
HPA tissue IHC evidence for GSTK1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — Medium consistency between antibody staining and RNA expression data. Pending external verification.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Endocrine cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Caudate | Glial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Smooth muscle | Smooth muscle cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced GSTK1 IHC Tips
Troubleshoot GSTK1 staining in chromogenic paraffin-section IHC using the catalog antibody’s tissue example and independent localisation evidence.
What retrieval should I try first when GSTK1 staining is weak?
Start with heat-mediated antigen retrieval in EDTA at pH 8.0 for GSTK1 paraffin-section IHC (datasheet M06112-1). Keep heating and cooling conditions consistent across sections, then compare staining with a no-primary control to separate retrieval effects from detection background (standard IHC practice). The selected tissue example used 1:50 primary antibody overnight at 4°C, so use those conditions as a reference when assessing retrieval (datasheet M06112-1). If staining remains weak, test a second retrieval condition on adjacent sections while retaining EDTA pH 8.0 as the comparator (standard IHC practice). Judge improvement by clearer granular cytoplasmic staining rather than stronger diffuse color (HPA: ubiquitous granular cytoplasmic expression).
Could fixation explain variable GSTK1 staining between paraffin sections?
The selected paraffin-section example does not report its fixative, so GSTK1-specific fixation sensitivity is unknown (datasheet M06112-1). Record fixative, time in fixative, and processing history for each specimen before attributing a staining difference to GSTK1 abundance (standard IHC practice). Compare adjacent sections with identical EDTA pH 8.0 retrieval, 1:50 primary antibody, and overnight incubation at 4°C (datasheet M06112-1). Where fixation histories differ, include a comparably processed reference tissue and assess morphology alongside staining (standard IHC practice). Neither the reported peroxisomal localisation nor the annotated modified residues establish a fixation preference for this antibody (UniProt Q9Y2Q3; datasheet M06112-1).
What staining pattern should count as plausible GSTK1 signal?
Expect granular cytoplasmic staining in tissue sections, consistent with the reported IHC profile and peroxisomal localisation (HPA: ubiquitous granular cytoplasmic expression; UniProt Q9Y2Q3: peroxisome). Evaluate granules within morphologically intact cells rather than counting diffuse pigment over damaged areas (standard IHC practice). Breast glandular cells have reported high staining and provide a relevant cellular reference for the selected breast cancer section (HPA: high in breast glandular cells; datasheet M06112-1: human breast cancer tissue). A nuclear-only pattern warrants scrutiny because the supplied localisation evidence points to peroxisomes (HPA: peroxisomes supported; UniProt Q9Y2Q3: peroxisome). Compare cellular distribution with a no-primary section before assigning weak puncta to GSTK1 (standard IHC practice).
How might isoforms or epitope accessibility affect GSTK1 IHC?
GSTK1 has 4 annotated isoforms, but the selected tissue caption does not identify the antibody epitope or establish isoform recognition (UniProt Q9Y2Q3: isoforms 1–4; datasheet M06112-1). Check the antibody’s epitope information, if available, against each isoform before interpreting an absent stain as absent total GSTK1 (standard antibody validation practice). The record lists modified residues, including acetyllysine at positions 71 and 85, without showing that either affects this antibody (UniProt Q9Y2Q3: modified residues). Keep EDTA retrieval at pH 8.0 constant during epitope comparisons (datasheet M06112-1). Use independently validated controls to investigate discordant staining rather than assigning it to a particular isoform or modification (standard IHC practice).
How should I check GSTK1 localisation by multiplex IF?
Use IF as a separate localisation check: GSTK1 is reported in peroxisomes, while tissue IHC shows granular cytoplasmic expression (HPA: peroxisomes supported; HPA: ubiquitous granular cytoplasmic expression). Pair GSTK1 with a validated marker of the expected cell type; breast glandular cells are a documented high-staining example (HPA: high in breast glandular cells; standard IF practice). Choose spectrally separated fluorophores and inspect an unstained section to avoid mistaking tissue autofluorescence for puncta (standard IF practice). GSTK1 has no annotated transmembrane segment, but its epitope’s membrane-facing side is unspecified; optimise permeabilisation for antibody access without assuming that side (UniProt Q9Y2Q3 topology; standard IF practice). Include single-label controls to assess channel bleed-through (standard IF practice).
What should I check when DAB background obscures GSTK1 granules?
Run no-primary and secondary-only controls to identify signal from the detection system before changing the GSTK1 primary antibody (standard IHC practice). The selected example used 10% goat serum blocking, a peroxidase-conjugated secondary, and DAB detection (datasheet M06112-1). Add an endogenous peroxidase block and inspect its control because native enzyme activity can produce DAB color independently of GSTK1 (standard chromogenic IHC practice). Reduce nonspecific binding by checking wash consistency and titrating the primary around the reported 1:50 condition on adjacent sections (datasheet M06112-1; standard IHC practice). Accept a change only when granular cytoplasmic contrast improves without increasing control-section staining (HPA: ubiquitous granular cytoplasmic expression; standard IHC practice).
How should I score GSTK1 staining across specimens? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and score granular cytoplasmic staining separately from diffuse background, matching the reported tissue pattern (HPA: ubiquitous granular cytoplasmic expression; standard IHC practice). For comparable fields, report the percentage of positive cells and an H-score using intensity categories 0–3; state the positivity threshold before scoring (standard IHC practice). If spatial distribution matters, report positive-cell density per mm² of viable tissue and exclude necrotic or folded regions (standard IHC practice). Normalise counts to the number of eligible cells or viable tissue area, and compare sections processed in the same staining run (standard IHC practice). Record compartment and cell type because GSTK1 expression is reported across many tissues (UniProt Q9Y2Q3: ubiquitous; HPA: low tissue specificity).
How can I distinguish true GSTK1 staining from artefact?
Treat intracellular granular cytoplasmic staining as plausible GSTK1 signal because tissue IHC reports that pattern and localisation evidence supports peroxisomes (HPA: ubiquitous granular cytoplasmic expression; HPA: peroxisomes supported). Check whether the stained cells fit the tissue context: breast glandular cells are reported high, whereas smooth muscle cells are reported not detected (HPA: breast glandular cells high; HPA: smooth muscle cells not detected). A nuclear-only pattern, section-edge emphasis, or color concentrated in necrosis needs investigation before biological interpretation (HPA: peroxisomes supported; standard IHC practice). Compare no-primary controls and apply endogenous peroxidase blocking to assess enzyme-derived DAB deposits (standard chromogenic IHC practice). Treat the HPA tissue pattern as supported but pending external verification (HPA: reliability description).
Boster reagents
Best GSTK1 / Glutathione S-transferase kappa 1 IHC Antibodies
Both antibodies have paraffin-section IHC images from human breast cancer tissue (catalog image captions); A06112-3 also has mouse and rat heart IHC images and a human breast cancer IF image (catalog image captions).
Real IHC data
Anti-GSTK1 Rabbit Monoclonal Antibody
Cat # M06112-1
Real IHC data
Anti-GSTK1 Antibody ®
Cat # A06112-3
M06112-1 has IHC images from human breast and prostate cancer paraffin sections; its listed reactivity is Human (M06112-1 catalog). A06112-3 has IHC images from human breast cancer and mouse and rat heart paraffin sections, plus a human breast cancer IF image (A06112-3 catalog image captions).
Which to pick: For human tissue IHC, choose the rabbit monoclonal M06112-1 at 1:50 using its documented EDTA pH 8.0 retrieval as a starting point (M06112-1 catalog and IHC caption). For IF/ICC, M06112-1 lists both applications, while A06112-3 lists IF and has a human tissue IF image (catalog applications; A06112-3 IF caption). For mouse or rat tissue IHC, choose A06112-3, which lists both species and shows heart-section IHC at 2 μg/ml after EDTA pH 8.0 retrieval; the fixative is unreported in both SKUs’ paraffin-section IHC captions (A06112-3 catalog and IHC captions; M06112-1 IHC caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9Y2Q3 (GSTK1_HUMAN, Glutathione S-transferase kappa 1).
- Human Protein Atlas. GSTK1 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. GSTK1 subcellular location (ICC-IF): Localized to the peroxisomes..
- Human Protein Atlas. GSTK1 antibody validation summary (2 antibodies).
- Prognostic biomarker GSTK1 in head and neck squamous cell carcinoma and its correlation with immune infiltration and DNA methylation. Frontiers in genetics 2023 — PMC10020208.
- GSTK1 suppresses HCC aggravation via L-carnitine metabolism by PGAM5/DRP1 complex-mediated mitochondrial quality control. Journal of experimental & clinical cancer research : CR 2025 — PMC12763885.
- miR-124 coordinates metabolic regulators acting at early stages of human neurogenesis. Communications biology 2024 — PMC11511827.
- Expression level and DNA methylation status of glutathione-S-transferase genes in normal murine prostate and TRAMP tumors. The Prostate 2009 — PMC2836025.
- PubMed PMID:14709161 — UniProt-cited evidence.
- PubMed PMID:14742434 — UniProt-cited evidence.
- PubMed PMID:11042152 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for GSTK1 (Glutathione S-transferase kappa 1). Expected localisation Granular cytoplasm (HPA tissue IHC); peroxisome (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet M06112-1). Validated IHC antibody: M06112-1 at 1:50 (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Smooth muscle. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human breast cancer tissue; fixative not specified (datasheet M06112-1); 2. Fixation: Image fixative and duration unreported (datasheet M06112-1); 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 M06112-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet M06112-1); 8. Primary antibody: Rabbit monoclonal (clone 21G63) anti-GSTK1, 1:50 (datasheet M06112-1); 9. Primary incubation: Overnight at 4 °C (datasheet M06112-1). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Smooth muscle cells have no detected staining (HPA tissue IHC); Isoform / epitope: 4 isoforms; epitope coverage is unknown (UniProt); Regulation: No specific expression regulator reported (UniProt). Evidence: UniProt Q9Y2Q3, HPA tissue IHC · Supported, HPA ICC-IF · peroxisomes., Datasheet M06112-1, PMC10020208. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/GSTK1/immunohistochemistry-ihc-guide.