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STK38L / Serine/threonine-protein kinase 38-like · IHC design guide
Design Immunohistochemistry for STK38L
Plan chromogenic STK38L staining in paraffin sections using the reported cytoplasmic and membranous tissue pattern (HPA tissue IHC). Compare results with the catalog antibody’s human tonsil IHC image (datasheet A06774), and interpret staining with its specificity limitation in mind (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
STK38L 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 and membranous tissue staining (HPA tissue IHC) | |
| Staining pattern | Glandular and endothelial cells; cytoplasmic/membranous (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A06774) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific). Selected-image fixative and duration unreported (datasheet A06774); verify before use. | |
| Caveat | Antibody staining may reflect more than one gene (HPA tissue IHC) | |
| Regulation | Expression regulation is unspecified (UniProt) | |
| Isoform / epitope | 2 isoforms; epitope differences are unspecified (UniProt) |
Section 1
Recommended STK38L IHC & IF Protocols
The catalog antibody protocol uses Tris-EDTA pH 9.0 retrieval (datasheet A06774). The published human PDAC tissue microarray protocol uses sodium citrate pH 6.0 (PMC5667982).
| Sample | Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A06774) |
| Fixation | Image fixative and duration unreported (datasheet A06774); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Tris-EDTA pH 9.0 (datasheet A06774); 20 min, 95–100 °C (standard) |
| 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-STK38L, 1:50 recommended; image 1:200 (datasheet A06774) |
| 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 | STK38L-positive staining in glandular cells of adrenal gland (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic and membranous expression in several different tissue types. No signal in the no-primary control. |
💡Decision noteStart with Tris-EDTA pH 9.0 for the catalog antibody (datasheet A06774); use citrate pH 6.0 when following the published protocol (PMC5667982).
Section 2
What Is the Expected STK38L Staining Pattern?
STK38L is expected in the cytoplasm and may appear along cell membranes or the actin cytoskeleton (UniProt Q9Y2H1; HPA tissue IHC). Look for staining in selected glandular, respiratory epithelial, endothelial, and neuronal cells (HPA tissue IHC). It has no transmembrane segment (UniProt Q9Y2H1 topology). Treat the pattern as provisional: HPA rates tissue IHC Approved but reports low agreement with RNA and cautions that the antibodies may target proteins from multiple genes (HPA tissue IHC).
| Cytoplasmic staining, sometimes with a cell-edge accent, in bronchial respiratory epithelium, colon endothelium, or caudate neurons. | This fits the reported compartments and Medium staining in those cell types (HPA tissue IHC). A cell-edge accent is compatible with membrane association; it does not imply that STK38L spans the membrane (UniProt Q9Y2H1 topology). |
| Strong nuclear-only staining, with little cytoplasmic signal. | A nuclear-only pattern conflicts with the reported cytoplasmic, cytoskeletal, and membrane locations (UniProt Q9Y2H1; HPA tissue IHC). Treat it as a suspected artefact and review morphology, counterstain, and detection controls before assigning it to STK38L (general IHC practice). |
| Prominent staining in adipocytes, liver cholangiocytes, or pancreatic exocrine cells. | HPA lists these cells as Not detected (HPA tissue IHC). Check for antibody cross-reactivity or endogenous detection activity before calling the signal target-specific; a single positive-looking section cannot resolve HPA's multi-gene targeting caution (HPA tissue IHC; general IHC practice). |
| Diffuse colour across stroma, empty spaces, and several unrelated cell types. | A widespread deposit without clear cellular boundaries is background rather than a convincing cytoplasmic pattern (general IHC practice; HPA tissue IHC). Compare it with a no-primary control and inspect blocking, washing, and chromogen development (general IHC practice). |
| No staining in bronchial respiratory epithelium despite intact tissue morphology. | HPA reports Medium staining there, so an absent signal calls for a technical check (HPA tissue IHC). Compare a known-positive section in the same run and review retrieval, antibody dilution, and detection according to the antibody's validated IHC workflow (general IHC practice). |
💡Expected STK38L appearanceCall a result consistent with STK38L when selected bronchial epithelial, colon endothelial, or caudate neuronal cells show discernible Medium cytoplasmic staining, with possible membrane accent (HPA tissue IHC); nuclear-only colour or strong signal in HPA-undetected cell types warrants investigation (UniProt Q9Y2H1; HPA tissue IHC).
| Cell type and compartment | HPA reports cytoplasmic and membranous staining across several tissues, including Medium signal in bronchial respiratory epithelium and colon endothelium (HPA tissue IHC). UniProt also places STK38L with the actin cytoskeleton and at membranes (UniProt Q9Y2H1). |
| Antibody evidence and specificity | The tissue IHC antibody HPA038623 is Approved, while HPA reports low staining-to-RNA consistency and cautions about multi-gene targeting (HPA antibodies; HPA tissue IHC). Interpret an apparently correct pattern with controls and avoid treating the rating as proof of specificity. |
| Isoforms and epitope coverage | UniProt lists 2 STK38L isoforms, but the supplied sources do not map antibody epitopes or establish isoform-specific staining (UniProt Q9Y2H1; HPA antibodies). An uneven cell pattern alone cannot identify which isoform is present. |
| Chromogenic detection activity | Endogenous enzyme activity can create colour unrelated to primary-antibody binding in enzyme-based IHC (general IHC practice). A no-primary control helps distinguish this from cellular staining; the supplied sources do not identify a STK38L-specific detection interference. |
| Situation | Likely cause | Next action |
|---|---|---|
| Positive-control epithelium has little or no colour. | Weak detection or a missed workflow step is possible; bronchial respiratory epithelium is reported at Medium staining (HPA tissue IHC; general IHC practice). | Run a known-positive section alongside the sample. Check the IHC-validated antibody's retrieval, dilution, and detection instructions, then inspect whether the control recovers (general IHC practice). |
| Nuclei dominate the staining. | Nuclear-only colour does not match the reported STK38L locations (UniProt Q9Y2H1; HPA tissue IHC). Counterstain or nonspecific detection may be obscuring the cellular pattern (general IHC practice). | Inspect a no-primary control and compare nuclear colour with the counterstain. Score STK38L only where a reproducible cytoplasmic or membrane-associated signal is clear (general IHC practice; HPA tissue IHC). |
| HPA-undetected cells appear strongly positive. | Adipocytes and pancreatic exocrine cells are listed as Not detected; cross-reactivity or endogenous detection activity is possible (HPA tissue IHC; general IHC practice). | Compare a no-primary control and an HPA-reported positive cell population in the same run. Keep the result provisional if the discrepancy persists, given HPA's multi-gene targeting caution (HPA tissue IHC). |
| Brown colour spreads beyond cell boundaries. | Diffuse chromogen deposit can reflect background from detection, insufficient washing, or overdevelopment (general IHC practice). It does not establish the cellular pattern reported by HPA (HPA tissue IHC). | Review the no-primary control, washing, blocking, and chromogen development. Reassess only after cell boundaries and cytoplasmic localisation can be judged (general IHC practice). |
| Does an IF/ICC image settle an uncertain IHC result? | HPA reports supported cytosolic ICC-IF localisation, but cautions that the antibodies may target proteins from multiple genes (HPA subcellular). The ICC-IF antibody HPA051324 is marked Supported; the tissue IHC antibody HPA038623 is Approved (HPA antibodies). | Use the cytosolic IF observation as a compartment check, then assess IHC cell type, controls, and antibody specificity on the stained section. IF/ICC protocol selection belongs in its separate guide (HPA subcellular; HPA tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing STK38L staining
A06774 · IHCImmunohistochemical analysis of paraffin-embedded human tonsil. 1, Antibody was diluted at 1:200 (4° overnight). 2, Tris-EDTA, pH9.0 was use
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000211455-STK38L/tissue/cerebral+cortex#imid_12570933
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000211455-STK38L/tissue/colon#imid_12568683
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000211455-STK38L/tissue/liver#imid_12568692
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000211455-STK38L/tissue/kidney#imid_12568693
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA051324; green = STK38L, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA051324; green = STK38L, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for STK38L IHC & IF
🧪Run breast first: glandular cells should stain (HPA: Medium in breast glandular cells). Run adipose tissue as the negative: adipocytes are not detected (HPA: Not detected in adipose tissue adipocytes); on the breast slide, adjacent adipocytes should show no convincing cellular signal, but treat them as a provisional internal negative rather than a validated control (HPA: Not detected in adipose tissue adipocytes).
Positive control tissue: Adrenal gland (Glandular cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show STK38L in A-431, U-251MG, U2OS, RPTEC/TERT1, hTERT-RPE1 (serum starved), with annotated localisation: Cytosol (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and an isotype control matched to the primary antibody’s host species and clonality (standard IHC practice). Use verified STK38L-knockout material as a biological negative; quench endogenous peroxidase before chromogenic detection and assess background in adipose-rich breast areas (standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported in the supplied evidence, and the selected A06774 paraffin-section caption does not state a fixative (A06774 tissue-IHC caption). That caption uses Tris-EDTA retrieval at pH 9.0 and primary antibody at 1:200 overnight at 4°C; it provides a starting condition, not evidence that retrieval is required (A06774 tissue-IHC caption). Neither frozen sections nor IF can be judged easier from the supplied evidence; breast adipocytes have a thin cytoplasmic rim that can make background hard to score (standard histology practice).
HPA tissue IHC evidence for STK38L
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low consistency between antibody staining and RNA expression data. Caution, targets protein from more than one gene.). 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 | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Breast | Glandular cells | Medium | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Medium | Protein (IHC) | HPA → |
| Caudate | Neuronal cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Liver | Cholangiocytes | Not detected | Protein (IHC) | HPA → |
| Oral mucosa | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
| Pancreas | Exocrine glandular cells | Not detected | Protein (IHC) | HPA → |
| Parathyroid gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced STK38L IHC Tips
Troubleshoot chromogenic STK38L staining in paraffin sections using the catalog antibody’s tissue image, protein annotation, and cell level staining evidence.
Which retrieval conditions should I try first for weak STK38L staining?
Start with heat-mediated retrieval in Tris-EDTA at pH 9.0 for paraffin sections (datasheet A06774). The catalog antibody’s human tonsil image used that buffer, a 1:200 primary dilution at 4°C overnight, and a 1:200 secondary for 30 minutes at room temperature (datasheet A06774). If staining remains weak, compare a modest change in retrieval time on matched sections while holding antibody dilution and detection constant; excessive heating can damage morphology (standard IHC practice). Judge the result by preserved tissue structure and plausible cytoplasmic or membranous signal, rather than stronger staining alone (HPA tissue IHC; standard IHC practice).
How should I troubleshoot fixation related loss of STK38L signal?
Target-specific fixation sensitivity is unknown: the catalog image identifies paraffin-embedded human tonsil but does not state its fixative (datasheet A06774). Do not attribute weak STK38L staining to a particular fixative without comparing sections with documented processing histories (standard IHC practice). On similarly processed sections, hold retrieval at Tris-EDTA pH 9.0 and primary incubation at 1:200, 4°C overnight while checking whether staining varies with preservation or tissue depth (datasheet A06774; standard IHC practice). Include a known staining control in the same run, assess morphology, and record fixation details so processing effects can be distinguished from biological variation (standard IHC practice).
What staining pattern is credible for STK38L in tissue?
Expect predominantly cytoplasmic staining, with possible membranous or cytoskeletal association: STK38L is annotated in cytoplasm, cytoskeleton, and membrane, and associates with actin (UniProt Q9Y2H1). Tissue images describe cytoplasmic and membranous expression across several tissue types, while the supported cellular imaging location is cytosol (HPA tissue IHC; HPA subcellular). STK38L has no transmembrane segment, so a crisp membrane outline alone should prompt review of morphology, detection background, and antibody specificity (UniProt Q9Y2H1 topology; standard IHC practice). Score cytoplasm and membrane separately where possible, comparing each compartment with a negative reagent control and adjacent cells (standard IHC practice).
Could isoforms or modifications explain inconsistent STK38L staining?
STK38L has 2 annotated isoforms, but the supplied catalog image does not identify the antibody epitope or establish which isoform it detects (UniProt Q9Y2H1; datasheet A06774). Its kinase domain spans residues 90–383, and annotated modified residues include Thr75, Ser282, and Thr442 (UniProt Q9Y2H1). Without an epitope map, do not assign a staining difference to isoform selection, phosphorylation, or retrieval masking; those explanations require direct validation (standard IHC practice). Compare serial sections under the same retrieval and detection conditions, then use an independent antibody or orthogonal measurement if the biological conclusion depends on isoform or modification specificity (standard IHC practice).
How can I cross-check an IHC pattern with multiplex IF?
Use IF as a separate check of the cell and compartment pattern, pairing STK38L with a validated marker for the cell population being scored in IHC (standard IF practice). Select spectrally separated fluorophores and assign the expected weaker signal to a channel with low tissue autofluorescence; inspect unstained and single-label controls before interpreting overlap (standard IF practice). STK38L is cytosolic and actin-associated, with reported membrane association but no transmembrane segment, so use controlled permeabilisation to access an intracellular epitope (UniProt Q9Y2H1 topology and localisation; standard IF practice). The supported cellular imaging location is cytosol, but the supplied IF summary cautions that its antibodies target proteins from multiple genes; concordance therefore does not establish specificity (HPA subcellular).
What should I check when brown signal appears across the section?
First compare the full staining run with a no-primary control to identify detection-system or endogenous-enzyme signal (standard IHC practice). For chromogenic peroxidase detection, check the peroxide block, washes, and DAB development time; these are general workflow controls, not evidence specific to STK38L (standard IHC practice). The catalog tonsil image used primary and secondary dilutions of 1:200, with the primary incubated at 4°C overnight and secondary for 30 minutes at room temperature (datasheet A06774). If diffuse colour persists, titrate detection exposure on matched sections and retain settings that preserve interpretable cytoplasmic or membranous contrast (HPA tissue IHC; standard IHC practice).
How should I score heterogeneous STK38L staining in IHC sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and anatomical region before scoring, then report either the percentage of positive cells with intensity categories or an H-score using the same thresholds across sections (standard IHC practice). If counting discrete positive cells, report density per mm² of viable tissue and state the area excluded for folds, edges, and necrosis (standard IHC practice). Record cytoplasmic and membranous staining separately because both patterns appear in the tissue profile, and specify the compartment used for the primary endpoint (HPA tissue IHC). Normalise to the number of eligible cells or evaluable tissue area, and compare sections processed and imaged under matched conditions (standard IHC practice).
When does apparent STK38L positivity need further validation?
A credible result combines cellular staining in an expected compartment with intact morphology and a clean no-primary control (UniProt Q9Y2H1 localisation; standard IHC practice). Investigate strong nuclear-only signal, staining confined to cut edges or necrosis, and colour persisting without primary antibody as possible localisation or chromogenic artefacts (UniProt Q9Y2H1 localisation; standard IHC practice). The tissue profile reports medium staining in several glandular, respiratory epithelial, neuronal, and endothelial cell populations, but also cautions that antibody staining has low consistency with RNA data and may detect proteins from more than one gene (HPA tissue IHC). For a consequential cell-type claim, confirm the pattern with an independent specificity check before treating intensity as STK38L abundance (HPA tissue IHC; standard IHC practice).
Boster reagents
Best STK38L / Serine/threonine-protein kinase 38-like IHC Antibodies
A06774 has a paraffin-section IHC image from human tonsil (image caption) and lists IF plus Human, Mouse and Rat reactivity (catalog: applications and reactivity).
Real IHC data
Anti-NDR2 STK38L Antibody
Cat # A06774
A06774 will render with an IHC image of paraffin-embedded human tonsil (image caption). Its catalog lists IHC and IF applications and Human, Mouse and Rat reactivity; no IF image is supplied (catalog: applications, reactivity and image captions).
Which to pick: For tissue IHC, choose A06774: its own image caption documents paraffin-embedded human tonsil with Tris-EDTA retrieval at pH 9.0 and primary antibody at 1:200 overnight at 4 °C; the fixative is unreported (image caption). For IF, A06774 is listed at 1:50, but ICC-specific validation and an IF image are unreported (catalog: IF dilution, applications and image captions). For cross-species work, A06774 is a rabbit polyclonal listed as reactive with Human, Mouse and Rat, while its IHC image documents human tissue only (catalog: host, dilution_raw and reactivity; image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9Y2H1 (ST38L_HUMAN, Serine/threonine-protein kinase 38-like).
- Human Protein Atlas. STK38L tissue IHC expression (reliability: Approved).
- Human Protein Atlas. STK38L subcellular location (ICC-IF): Localized to the cytosol. Caution: Based on antibodies targeting proteins from multiple genes..
- Human Protein Atlas. STK38L antibody validation summary (2 antibodies).
- STK38L kinase ablation promotes loss of cell viability in a subset of KRAS-dependent pancreatic cancer cell lines. Oncotarget 2017 — PMC5667982.
- PubMed PMID:15037617 — UniProt-cited evidence.
- PubMed PMID:10231032 — UniProt-cited evidence.
- PubMed PMID:12168954 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for STK38L (Serine/threonine-protein kinase 38-like). Expected localisation Cytoplasmic and membranous tissue staining (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A06774). Validated IHC antibody: A06774 at 1:50 recommended; image 1:200 (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A06774); 2. Fixation: Image fixative and duration unreported (datasheet A06774); 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: Tris-EDTA pH 9.0 (datasheet A06774); 20 min, 95–100 °C (standard); 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-STK38L, 1:50 recommended; image 1:200 (datasheet A06774); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific). Selected-image fixative and duration unreported (datasheet A06774); verify before use.; Caveat: Antibody staining may reflect more than one gene (HPA tissue IHC); Isoform / epitope: 2 isoforms; epitope differences are unspecified (UniProt); Regulation: Expression regulation is unspecified (UniProt). Evidence: UniProt Q9Y2H1, HPA tissue IHC · Approved, HPA ICC-IF · cytosol. Caution: Based on antibodies targeting proteins from…, Datasheet A06774, PMC5667982. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/STK38L/immunohistochemistry-ihc-guide.