PLK2 / Serine/threonine-protein kinase PLK2 · IHC design guide

Design Immunohistochemistry for PLK2

Plan chromogenic PLK2 IHC on paraffin sections using the catalog antibody at 0.5–1 μg/mL (datasheet A02881). Assess cytoplasmic staining in glandular cells and account for its low consistency with RNA expression (HPA tissue IHC).

Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use

Immunohistochemistry protocol sheet for PLK2 (IHC for PLK2): expected localisation Predominantly cytoplasmic in tissue (HPA tissue IHC), antibody A02881, validated IHC image, and IHC protocol steps — Printable **PLK2** IHC protocol sheet — expected localisation Predominantly cytoplasmic in tissue (HPA tissue IHC), antibody A02881, controls and protocol steps. Open the full PLK2 IHC guide →

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PLK2 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	Predominantly cytoplasmic in tissue (HPA tissue IHC)
	Staining pattern	Cytoplasmic in most tissues; high in glandular cells (HPA tissue IHC)
	Antigen retrieval	Citrate pH 6 HIER, heat-mediated (datasheet A02881)
	Positive control ⓘ	Adrenal gland+4 more · see all
	Negative control ⓘ	None in HPA (detected in all 45 tissues); use no-primary + isotype controls

Important caveats

Reasons your staining may differ from the expected pattern.

	Fixation	Keep fixation consistent (standard IHC practice; not target-specific); Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A02881)
	Caveat	Staining has low consistency with RNA expression (HPA tissue IHC)
	Regulation	p53 induction suggests a stress response (UniProt)
	Isoform / epitope	2 isoforms; confirm epitope coverage (UniProt)

Section 1

Recommended PLK2 IHC & IF Protocols

The catalog antibody’s IHC-P protocol (datasheet A02881) is accompanied by four published PLK2 IHC protocols (PMC7300400; PMC12460256; PMC5487358; PMC7504392).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human tonsil tissues; fixative not specified (datasheet A02881)
Fixation	Image fixative and duration unreported (datasheet A02881); verify before use.
Sectioning	4–5 µm sections on charged slides (standard)
Deparaffinisation	Xylene, graded ethanol series to water (standard)
Antigen retrieval	Heat retrieval: Citrate pH 6, 20 min (datasheet A02881)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% goat serum (datasheet A02881)
Primary antibody	Rabbit anti-PLK2, 0.5-1μg/ml (datasheet A02881)
Primary incubation	Overnight at 4 °C (datasheet A02881)
Detection	Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A02881)
Counterstain	Hematoxylin, blue, dehydrate and mount (standard)
Expected result	PLK2-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in most tissues. No signal in the no-primary control.

💡Decision noteStart with heated citrate pH 6 retrieval (datasheet A02881; PMC7504392). Consider pH 8.0 EDTA during optimization (PMC5487358).

Section 2

What Is the Expected PLK2 Staining Pattern?

PLK2 staining in paraffin sections is expected mainly in the cytoplasm of glandular, respiratory epithelial and neuronal cells, depending on tissue (HPA: cytoplasmic expression in most tissues; HPA: High in the listed cells). Centrosomal or dendritic localization is biologically plausible (UniProt Q9NYY3: subcellular location). PLK2 has no transmembrane segment (UniProt Q9NYY3: topology). Interpret staining cautiously: HPA rates tissue IHC Approved but reports low consistency with RNA expression (HPA: reliability).

What am I looking at on my slide?
Cytoplasmic staining in colon glandular cells or bronchial respiratory epithelial cells.	This matches reported high staining in those cells (HPA: High in colon glandular cells; HPA: High in bronchial respiratory epithelial cells). Judge intensity against neighboring cells and the no-primary control (general IHC practice).
Predominantly nuclear staining in a paraffin section, with little cytoplasmic signal.	This differs from the reported tissue IHC profile and warrants review of controls (HPA: cytoplasmic expression in most tissues). Nuclear signal alone is not proof of an artefact: ICC-IF also reports approved nucleoplasmic localization (HPA: subcellular location).
Strong staining in a cell population outside the reported high-staining populations.	Check whether the signal follows tissue structure and survives control review; cross-reactivity or endogenous chromogenic activity is possible (general IHC practice). HPA reports low tissue specificity, so an unlisted cell type cannot be declared PLK2-negative (HPA: RNA specificity).
Uniform haze across cells, extracellular space and blank regions.	A pattern without cell boundaries is difficult to assign to PLK2 (general IHC practice). Review no-primary staining, blocking, washing and detection conditions before interpreting intensity; HPA's cytoplasmic profile does not validate diffuse background (HPA: tissue IHC profile).
No staining in colon glandular cells or cerebellar Purkinje cells.	Those cells are reported High, so absent signal calls for a check of section quality, retrieval, antibody and detection workflow (HPA: High in colon glandular cells; HPA: High in Purkinje cells; general IHC practice). It does not alone establish absent PLK2 expression.

💡Expected PLK2 appearanceCall a result consistent when identifiable glandular, respiratory epithelial or neuronal cells show cytoplasmic staining, potentially strong in listed High populations (HPA: tissue IHC profile); broad haze or control-positive chromogen is suspect (general IHC practice).

How each factor affects the staining
Tissue and cell context	High staining is reported in several glandular populations, bronchial respiratory epithelium and selected neurons; adipocytes and chondrocytes are reported Low (HPA: tissue IHC). These are comparison points, not universal positive or negative controls.
Subcellular context	UniProt places PLK2 in cytoplasm, centrosomes, centrioles and dendrites (UniProt Q9NYY3: subcellular location). Its centrosomal distribution changes from early G1 to S phase (UniProt Q9NYY3); routine chromogenic IHC may not resolve individual centrioles (general IHC practice).
Protein form and topology	PLK2 has two reported isoforms and a 1–685 amino-acid chain, with no signal peptide, propeptide or transmembrane segment (UniProt Q9NYY3: isoforms, processing and topology). The payload does not identify the catalog antibody's epitope, so isoform coverage cannot be assigned.
Strength of IHC evidence	HPA calls tissue IHC Approved while noting low consistency between staining and RNA expression; CAB009624 is IHC Approved, whereas HPA069329 has no listed IHC status (HPA: reliability; HPA: antibodies). Approval does not settle every discordant cell-level result.
IF/ICC question: should its pattern match paraffin IHC?	Not necessarily. ICC-IF reports approved nucleoplasm, mitochondria and cytosol locations (HPA: subcellular location), while tissue IHC is described as mainly cytoplasmic (HPA: tissue IHC profile). Compare compartments within each application and its controls (general IHC practice).
Antigen retrieval and fixation	Retrieval conditions can affect paraffin IHC generally (general IHC practice). No source here reports PLK2-specific fixation sensitivity or an epitope-specific retrieval requirement; do not attribute a weak or absent PLK2 result to either without controlled comparison.

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
A reported High population has no signal.	The section, antibody incubation, retrieval or detection may have failed (general IHC practice); a single negative section does not overturn the reported High pattern (HPA: tissue IHC).	Run a reported High tissue alongside the sample, inspect tissue preservation and verify each detection step (HPA: tissue IHC; general IHC practice). Optimize retrieval empirically; no PLK2-specific setting is supplied.
Nuclear staining dominates the paraffin section.	This diverges from HPA's mainly cytoplasmic tissue profile, although nucleoplasm is an approved ICC-IF location (HPA: tissue IHC; HPA: subcellular location).	Review the no-primary control and the distribution across cell types; report nuclear and cytoplasmic signals separately (general IHC practice). Avoid calling nuclear signal either confirmed PLK2 or artefact from compartment alone.
Strong signal appears in an unexpected cell population.	Cross-reactivity or endogenous detection activity is possible (general IHC practice). Low tissue RNA specificity also limits claims that unlisted cells must be negative (HPA: RNA specificity).	Check morphology and no-primary staining, then compare with a reported High cell population in the same run (general IHC practice; HPA: tissue IHC). Record the discordant population without assigning identity from stain alone.
Diffuse stain obscures cell boundaries.	Background from nonspecific binding, insufficient washing or detection chemistry can obscure localization (general IHC practice). This cannot be equated with HPA's cytoplasmic profile (HPA: tissue IHC).	Inspect no-primary and reagent controls; review blocking, washing and detection exposure as general workflow variables (general IHC practice). Reassess only where cytoplasm can be distinguished from extracellular background.
Chromogen develops in a no-primary section.	Primary-antibody-independent detection, including endogenous activity, can produce signal (general IHC practice). Its presence cannot support a PLK2-specific call.	Identify the detection chemistry and use its appropriate endogenous-activity control; adjust blocking or detection conditions as needed (general IHC practice). Re-evaluate sample staining after control signal is resolved.
A high-intensity tissue shows little discernible centrosomal puncta.	HPA describes broad cytoplasmic tissue staining, while UniProt's centrosomal localization is subcellular and cell-cycle dependent (HPA: tissue IHC; UniProt Q9NYY3: subcellular location).	Score the supported cell-type and cytoplasmic pattern first (HPA: tissue IHC). Do not require resolved centrioles for a positive chromogenic section; optical resolution and section plane limit puncta assessment (general IHC practice).

Source: UniProt Q9NYY3 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing PLK2 staining

IHC analysis of PLK2 using anti-PLK2 antibody (A02881). PLK2 was detected in paraffin-embedded section of human tonsil tissues. Heat mediated antigen retrieval was performed in citrate buffer (pH6, epitope retrieval solution) for 20 mins. The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 1μg/ml rabbit anti-PLK2 Antibody (A02881) overnight at 4°C. Biotinylated goat anti-rabbit IgG was used as secondary antibody and incubated for 30 minutes at 37°C. The tissue section was developed using Strepavidin-Biotin-Complex (SABC)(Catalog # SA1022) with DAB as the chromogen.

A02881 · IHCIHC analysis of PLK2 using anti-PLK2 antibody (A02881). PLK2 was detected in paraffin-embedded section of human tonsil tissues. Heat mediate

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000145632-PLK2/tissue/cerebral+cortex#imid_3575856

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000145632-PLK2/tissue/colon#imid_3530302

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000145632-PLK2/tissue/liver#imid_3530311

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000145632-PLK2/tissue/kidney#imid_3530320

HPA · ICC-IF HaCaTHuman Protein Atlas immunofluorescence, HaCaT, antibody HPA069329; green = PLK2, blue = nucleus, red = microtubules.

← swipe / scroll for more images →

Real IHC / IF data behind the staining-pattern expectations in this section.

Sample controls for PLK2 IHC & IF

🧪Run cerebellum first and assess Purkinje cells for staining (HPA: High in Purkinje cells). HPA lists no negative tissue and detects PLK2 in all 45 scored tissues, so no-primary and isotype controls carry the negative; cells on the positive slide can serve as internal negatives only if independently shown to lack PLK2, in which case they should show counterstain and background alone (HPA: no negative rows; standard IHC practice).

Positive control tissue: Adrenal gland (Glandular cells, HPA High)

Negative control tissue: None in HPA: PLK2 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PLK2 in HaCaT, U-251MG, U2OS, A-431, with annotated localisation: Nucleoplasm (approved), Mitochondria (approved), Cytosol (approved) (HPA subcellular).

Technical controls: Include a no-primary, secondary-only slide, an isotype control matched to the rabbit primary antibody’s immunoglobulin class and clonality where known, and a matched PLK2-knockout specimen as a biological negative (selected IHC caption: rabbit primary; standard IHC practice). For cerebellum, quench endogenous peroxidase before DAB detection and account for neuronal pigment when interpreting signal; check endogenous biotin if using the caption’s streptavidin–biotin detection (selected IHC caption: SABC/DAB; standard IHC practice).

⚠️Feasibility: Paraffin-section staining is documented with citrate retrieval at pH 6 for 20 minutes, but retrieval dependence has not been established (selected IHC caption). A PLK2-specific fixation window or fixation effect is unreported, and the exact A02881 caption does not state a fixative (selected IHC caption). The supplied evidence does not establish whether frozen sections or IF are easier than paraffin IHC; cerebellar neuronal pigment can complicate chromogenic interpretation (HPA: High in Purkinje cells; standard IHC practice).

HPA tissue IHC evidence for PLK2

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low consistency between antibody staining and RNA expression data.). 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	Glandular cells	High	Protein (IHC)	HPA →
Breast	Glandular cells	High	Protein (IHC)	HPA →
Bronchus	Respiratory epithelial cells	High	Protein (IHC)	HPA →
Cerebellum	Purkinje cells	High	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
None in HPA: PLK2 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.

Section 3

Advanced PLK2 IHC Tips

Troubleshoot PLK2 staining in paraffin sections by checking retrieval, compartment, controls and cell-level scoring before interpreting chromogenic signal.

What retrieval should I start with if PLK2 staining is weak?

Start with heat-mediated retrieval in citrate buffer at pH 6 for 20 minutes (datasheet A02881). That condition precedes PLK2 staining in a paraffin-embedded human tonsil section using 1 μg/ml primary antibody overnight at 4°C (datasheet A02881). If signal remains weak, compare a longer or shorter heating interval on matched sections while keeping detection and exposure to DAB consistent (standard IHC practice). Include a section processed without primary antibody to identify detection background (standard IHC practice). Record retrieval time and staining intensity together, because a stronger brown signal alone does not establish PLK2 specificity (standard IHC practice).

Could fixation explain weak or uneven PLK2 staining?

Target-specific PLK2 fixation sensitivity is unknown: the selected tissue caption describes a paraffin-embedded section but does not state its fixative (datasheet A02881). Check the specimen record for fixative, fixation duration and delay before fixation, then compare sections with documented processing histories (standard IHC practice). Keep citrate pH 6 retrieval for 20 minutes constant during that comparison (datasheet A02881). Examine morphology alongside signal, since damaged or poorly preserved areas can make chromogenic staining difficult to interpret (standard IHC practice). Do not attribute a fixation effect to PLK2 from tissue staining patterns or its protein features alone.

Where should convincing PLK2 staining appear in a tissue section?

Assess PLK2 primarily within cells: tissue IHC reports cytoplasmic expression in most tissues (HPA: tissue IHC), while protein annotation places it in the cytoplasm, dendrites and centrosomal structures (UniProt Q9NYY3: subcellular location). A compact centrosomal signal may occupy only a small part of a cell, and its association with centrioles changes between early G1 and the onset of S phase (UniProt Q9NYY3: subcellular location). Interpret diffuse extracellular DAB cautiously and compare it with cell boundaries and a section without primary antibody (standard IHC practice). Nucleoplasmic and mitochondrial locations have also been reported by cell imaging, so compartment alone cannot prove specificity (HPA: subcellular).

How do isoforms and epitope placement affect PLK2 IHC interpretation?

PLK2 has 2 annotated isoforms, but the supplied antibody caption does not identify its epitope or establish isoform coverage (UniProt Q9NYY3: isoforms; datasheet A02881). Review the antibody's immunogen or mapped epitope before calling a negative section isoform-negative (standard antibody validation practice). The annotated kinase domain spans residues 82–334, whereas polo boxes span 503–581 and 601–685 (UniProt Q9NYY3: domains). Phosphothreonine at residue 239 is annotated, but its effect on this antibody's staining is unestablished (UniProt Q9NYY3: modified residue). Compare staining with an independently validated antibody to a different mapped epitope when an isoform-specific conclusion is essential (standard IHC practice).

How should I investigate PLK2 by multiplex IF after seeing a DAB pattern?

Treat IF/ICC as a separate assay: the selected antibody evidence describes chromogenic staining of a paraffin section, not IF performance (datasheet A02881). For a neuronal specimen, pair PLK2 with a validated neuronal cell marker; neuronal cells in cerebral cortex show high tissue IHC staining in the supplied profile (HPA: cerebral cortex neuronal cells). Choose spectrally separated fluorophores and inspect unstained tissue in each channel to avoid mistaking autofluorescence for colocalisation (standard IF practice). PLK2 lacks a transmembrane segment, so use permeabilisation appropriate for an intracellular epitope and validate that step for the IF specimen (UniProt Q9NYY3: topology; standard IF practice). Include single-stain and no-primary controls when assessing overlap (standard IF practice).

What should I check when PLK2 DAB staining is widespread?

Compare the stained section with a no-primary control and inspect pigment, folds and section edges before assigning widespread brown signal to PLK2 (standard IHC practice). The reported tissue profile is broadly cytoplasmic, but its approved staining has low consistency with RNA expression data (HPA: tissue IHC). In the selected tonsil example, blocking used 10% goat serum before an overnight incubation with 1 μg/ml primary antibody at 4°C (datasheet A02881). Check peroxidase blocking and wash adequacy, then shorten DAB development if the control also darkens (standard chromogenic IHC practice). Judge any change against preserved cellular morphology and the control, rather than total brown area alone (standard IHC practice).

How should I quantify PLK2 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and tissue region before scoring, then report the percentage of positive cells and an intensity-weighted H-score using the same thresholds across slides (standard IHC quantification practice). Normalize positive-cell counts to all evaluable cells of that population, or report positive-cell density per mm² of evaluable tissue (standard IHC quantification practice). Exclude folds, necrosis and section edges using the same rules for every specimen (standard IHC quantification practice). Because the supplied profile includes high glandular staining in colon and high neuronal staining in cerebral cortex, do not pool unlike cell populations into one score (HPA: colon glandular cells; HPA: cerebral cortex neuronal cells). Report retrieval and staining batch alongside scores (standard IHC practice).

How can I distinguish true PLK2 staining from artefact?

Look for cell-associated staining in a plausible compartment and compare its distribution with a no-primary section; PLK2 is annotated in the cytoplasm and centrosomal structures (UniProt Q9NYY3: subcellular location; standard IHC practice). The tissue profile reports high staining in appendix glandular cells and low staining in adipocytes, but also reports low consistency between antibody staining and RNA expression (HPA: appendix glandular cells; HPA: adipocytes; HPA: tissue IHC reliability). Treat signal confined to necrosis, section edges or endogenous peroxidase-positive areas as suspect until controls resolve it (standard IHC practice). A plausible compartment or cell type supports interpretation but does not independently identify the antigen (standard IHC practice). Confirm consequential findings with an independently validated reagent or orthogonal expression evidence (standard IHC practice).

Boster reagents

Best PLK2 / Serine/threonine-protein kinase PLK2 IHC Antibodies

Two anti-PLK2 antibodies have paraffin-section IHC images from human tonsil, human lung cancer, and rat intestine and brain; PA2131 also has a chromogenic ICC image from A549 cells (catalog image captions).

Real IHC data

Anti-PLK2 Antibody ®

Cat # A02881

View product →

A02881 has a paraffin-section IHC image from human tonsil (A02881 IHC caption). PA2131 has paraffin-section IHC images from human lung cancer, rat intestine, and rat brain, plus a DAB-based ICC image from A549 cells (PA2131 image captions).

Which to pick: For tissue IHC, choose A02881 for its human tonsil example or PA2131 for its human and rat tissue examples; neither IHC caption reports the fixative (each SKU’s IHC caption). For ICC, PA2131 lists that application and shows a chromogenic A549 example; fluorescent IF validation is unreported (PA2131 applications and ICC caption). For cross-species IHC, PA2131 has human and rat tissue images; both antibodies list human, mouse, and rat reactivity, but neither has a mouse IHC image in this payload (catalog reactivity; each SKU’s IHC captions).

Each figure is that product's own IHC / IF validation image from its datasheet.

References

UniProt Consortium. UniProt entry Q9NYY3 (PLK2_HUMAN, Serine/threonine-protein kinase PLK2).
Human Protein Atlas. PLK2 tissue IHC expression (reliability: Approved).
Human Protein Atlas. PLK2 subcellular location (ICC-IF): Mainly localized to the nucleoplasm, cytosol and mitochondria..
Human Protein Atlas. PLK2 antibody validation summary (2 antibodies).
PLK2 modulation of enriched TAp73 affects osteogenic differentiation and prognosis in human osteosarcoma. Cancer medicine 2020 — PMC7300400.
PLK2 as a key regulator of glycolysis and immune dysregulation in polycystic ovary syndrome. Frontiers in immunology 2025 — PMC12460256.
PLK2 Plays an Essential Role in High D-Glucose-Induced Apoptosis, ROS Generation and Inflammation in Podocytes. Scientific reports 2017 — PMC5487358.
Targeting Adaptive IRE1α Signaling and PLK2 in Multiple Myeloma: Possible Anti-Tumor Mechanisms of KIRA8 and Nilotinib. International journal of molecular sciences 2020 — PMC7504392.
PubMed PMID:11696980 — UniProt-cited evidence.
PubMed PMID:15372022 — UniProt-cited evidence.
PubMed PMID:15489334 — UniProt-cited evidence.