SNAPIN / SNARE-associated protein Snapin · IHC design guide

Design Immunohistochemistry for SNAPIN

Plan paraffin section IHC for SNAPIN using its reported cytoplasmic tissue pattern and high staining in lung macrophages (HPA tissue IHC). This guide covers fixation consistency, antibody dilution, chromogenic detection, and interpretation, with medium IHC–RNA consistency in mind (HPA tissue IHC).

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

Immunohistochemistry protocol sheet for SNAPIN (IHC for SNAPIN): expected localisation General cytoplasmic tissue staining (HPA tissue IHC), antibody A03491, validated IHC image, and IHC protocol steps — Printable **SNAPIN** IHC protocol sheet — expected localisation General cytoplasmic tissue staining (HPA tissue IHC), antibody A03491, controls and protocol steps. Open the full SNAPIN IHC guide →

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SNAPIN 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	General cytoplasmic tissue staining (HPA tissue IHC)
	Staining pattern	Cytoplasmic staining, high in lung macrophages (HPA tissue IHC)
	Antigen retrieval	Citrate pH 6.0 HIER, heat-mediated (datasheet A03491)
	Positive control ⓘ	Adipose tissue+4 more · see all
	Negative control ⓘ	Smooth muscle

Important caveats

Reasons your staining may differ from the expected pattern.

	Fixation	Keep fixation consistent across paraffin sections (standard IHC practice; not target-specific)
	Caveat	Medium IHC–RNA consistency; verify specificity (HPA tissue IHC)
	Regulation	No expression regulator established (UniProt)
	Isoform / epitope	0 annotated isoforms; epitope dependence unknown (UniProt)

Section 1

Recommended SNAPIN IHC & IF Protocols

The catalog antibody’s IHC-P protocol is accompanied by 3 published SNAPIN IHC protocols covering mouse pancreas, human liver cancer specimens, and rat brain (PMC8237857; PMC12775592; PMC12338511).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded rat brain tissue; fixative not specified (datasheet A03491)
Fixation	Image fixative and duration unreported (datasheet A03491); 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 6.0 (datasheet A03491); 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-SNAPIN, 1:50-1:200 (datasheet A03491)
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	SNAPIN-positive staining in adipocytes of adipose tissue (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression. No signal in the no-primary control.

💡Decision noteStart with heat-mediated citrate retrieval at pH 6.0 for paraffin sections (datasheet A03491; PMC12775592). The frozen-pancreas protocol specifies microwave citrate retrieval (PMC8237857).

Section 2

What Is the Expected SNAPIN Staining Pattern?

SNAPIN should appear mainly cytoplasmic in tissue IHC, with signal in several cell types, including lung macrophages, cerebellar Purkinje cells, and kidney glomerular cells (HPA: general cytoplasmic expression; High in each listed cell type). Its reported membrane associations include Golgi, lysosomal, and vesicle membranes, despite no transmembrane segment (UniProt O95295: subcellular location; topology). HPA rates the tissue IHC pattern Approved, with medium consistency against RNA and external verification pending (HPA: reliability).

What am I looking at on my slide?
Cytoplasmic staining in lung macrophages, with a clear cell-associated pattern.	This fits the reported high staining in macrophages and general cytoplasmic IHC profile (HPA: lung macrophages High; tissue IHC profile). Judge the labeled cells and surrounding background separately; a dark field alone does not establish a convincing cellular pattern (general IHC practice).
Cytoplasmic signal in Purkinje cells or cells in kidney glomeruli.	Both are reported high-staining populations and can serve as tissue-pattern references (HPA: cerebellum Purkinje cells High; kidney cells in glomeruli High). The reference is supportive, not definitive, because HPA reports only medium consistency with RNA and pending external verification (HPA: reliability description).
Predominantly strong nuclear staining without a convincing cytoplasmic component.	Treat this as discordant with the general tissue IHC pattern and review specificity and detection background (HPA: general cytoplasmic expression). Do not automatically reject discrete nucleolar signal in IF/ICC: HPA reports that additional location with uncertain confidence (HPA: subcellular location).
Prominent staining of smooth muscle cells while expected cytoplasmic staining is weak.	Smooth muscle cells are reported as not detected, so this distribution raises concern for cross-reactivity or endogenous chromogenic activity (HPA: smooth muscle cells Not detected; general IHC practice). Check morphology and detection controls before calling the smooth muscle signal SNAPIN-specific (general IHC practice).
Widespread diffuse color obscures cell boundaries, or no signal appears in a reported high-staining population.	Diffuse color limits localization scoring; absent signal in a reported high-staining population makes the run hard to interpret (general IHC practice; HPA: lung macrophages High). Review controls and the detection workflow before treating either appearance as a true expression result (general IHC practice).

💡Expected SNAPIN appearanceCall positive a cell-associated, mainly cytoplasmic signal in a reported high-staining population such as lung macrophages; prominent smooth muscle staining or strong nuclear-only color warrants review (HPA: tissue IHC profile; lung macrophages High; smooth muscle cells Not detected).

How each factor affects the staining
Compartment and topology	SNAPIN is annotated in cytosol, the perinuclear region, and on Golgi, lysosomal, and vesicle membranes; it has no transmembrane segment (UniProt O95295: subcellular location; topology). Interpret tissue IHC primarily against HPA's general cytoplasmic pattern, without requiring one sharply defined organelle pattern in chromogenic sections (HPA: tissue IHC profile; general IHC practice).
Choice of tissue reference	Adipocytes, adrenal glandular cells, bone marrow hematopoietic cells, ovary follicle cells, lung macrophages, Purkinje cells, and kidney glomerular cells are reported High (HPA: tissue IHC). Smooth muscle cells are reported Not detected (HPA: tissue IHC). These are observed patterns, not guarantees for every specimen or run (HPA: Approved; medium consistency; external verification pending).
Antibody evidence	The listed antibody HPA046974 is Approved for IHC; HPA's tissue IHC reliability description says external verification is pending (HPA: antibody validation; tissue IHC reliability). Compare compartment and cell distribution with the HPA observations, and keep uncertain cases provisional rather than treating an Approved label as independent proof of specificity (general IHC practice).
Processing and modified residues	UniProt lists no signal peptide, propeptide, annotated isoforms, or glycosylation sites, and lists several modified residues (UniProt O95295: processing; isoforms; glycosylation; modified residues). Those annotations do not identify the antibody epitope or predict an antigen-retrieval condition or fixation sensitivity; no target-specific effect is established by the supplied sources.
IF/ICC Q: What localization is reported?	A: Golgi apparatus is the approved main location in HPA ICC-IF; nucleoli are an additional uncertain location (HPA: subcellular). That IF/ICC observation can inform compartment review, while tissue IHC interpretation follows HPA's general cytoplasmic profile (HPA: tissue IHC profile).

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
No stain in lung macrophages or another reported High population.	The run may have insufficient detectable signal, or the chosen cells may be absent from the examined area (general IHC practice; HPA: lung macrophages High).	Confirm the expected cells on the counterstained section, then review the run's positive control, antigen-retrieval and detection records (general IHC practice). Do not infer that SNAPIN is absent from this single negative slide.
Smooth muscle cells stain prominently.	This conflicts with HPA's Not detected observation and may reflect cross-reactivity or endogenous detection activity (HPA: smooth muscle cells Not detected; general IHC practice).	Check a no-primary control and the chromogenic detection controls; compare the same section's expected cytoplasmic populations before assigning the smooth muscle color to SNAPIN (general IHC practice; HPA: tissue IHC profile).
Color is diffuse across tissue or obscures cell borders.	Background from blocking, washing, or detection can prevent compartment assignment (general IHC practice).	Review no-primary control, blocking, washes, and detection exposure; score SNAPIN only where cell-associated cytoplasmic signal remains distinguishable (general IHC practice; HPA: general cytoplasmic expression).
Signal is mainly nuclear in the chromogenic section.	The distribution is discordant with HPA's general cytoplasmic tissue IHC profile; IF/ICC nucleolar localization is reported with uncertain confidence (HPA: tissue IHC profile; subcellular location).	Review morphology, counterstain, and no-primary control before interpreting the nuclear color; seek a convincing cytoplasmic component in a reported positive population (general IHC practice; HPA: tissue IHC).
Reported High and Not detected populations look equally stained.	Poor contrast between the populations weakens the tissue-pattern evidence and may indicate background or a specificity problem (HPA: High populations; smooth muscle cells Not detected; general IHC practice).	Score cell types separately, inspect no-primary control, and compare intensity with HPA's population-specific observations; flag an unresolved distribution as inconclusive (general IHC practice; HPA: tissue IHC).
Punctate or perinuclear cytoplasmic staining is hard to classify.	UniProt reports perinuclear, Golgi, lysosomal, and vesicle-associated locations, while HPA summarizes tissue IHC as generally cytoplasmic (UniProt O95295: subcellular location; HPA: tissue IHC profile).	Record the observed compartment and cell type without assigning a specific organelle from chromogenic morphology alone; compare with HPA's reported positive populations (general IHC practice; HPA: tissue IHC).

Source: UniProt O95295 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing SNAPIN staining

Immunohistochemistry of paraffin-embedded rat brain using SNAPIN Rabbit pAb at dilution of 1:200 .Perform high pressure antigen retrieval with 10 mM citrate buffer pH 6.0 before commencing with IHC staining protocol.

A03491 · IHCImmunohistochemistry of paraffin-embedded rat brain using SNAPIN Rabbit pAb at dilution of 1:200 .Perform high pressure antigen retrieval wi

Immunohistochemistry of paraffin-embedded rat kidney using SNAPIN Rabbit pAb at dilution of 1:200 .Perform high pressure antigen retrieval with 10 mM citrate buffer pH 6.0 before commencing with IHC staining protocol.

A03491 · IHCImmunohistochemistry of paraffin-embedded rat kidney using SNAPIN Rabbit pAb at dilution of 1:200 .Perform high pressure antigen retrieval w

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000143553-SNAPIN/tissue/cerebral+cortex#imid_12887879

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000143553-SNAPIN/tissue/colon#imid_12887805

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000143553-SNAPIN/tissue/liver#imid_12887806

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000143553-SNAPIN/tissue/kidney#imid_12887807

HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA046974; green = SNAPIN, blue = nucleus, red = microtubules.

← swipe / scroll for more images →

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

Sample controls for SNAPIN IHC & IF

🧪Run cerebellum first and require staining in Purkinje cells (HPA: High in Purkinje cells). Run smooth muscle as the negative tissue (HPA: Not detected in smooth muscle cells); on the cerebellar slide, use non-Purkinje cells that show counterstain without specific chromogen as internal background comparators, without assuming all non-Purkinje cells are SNAPIN-negative (HPA: High in Purkinje cells).

Positive control tissue: Adipose tissue (Adipocytes, HPA High)

Negative control tissue: Smooth muscle (HPA Not detected)

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show SNAPIN in A-431, U-251MG, U2OS, with annotated localisation: Golgi apparatus (approved) (HPA subcellular).

Technical controls: Include a no-primary, secondary-only control, a concentration-matched polyclonal rabbit IgG isotype control, and SNAPIN knockout tissue or a peptide-block control if available (A03491 caption: rabbit pAb; standard IHC practice). Quench endogenous peroxidase and inspect the cerebellar slide for residual chromogenic background (standard chromogenic IHC practice).

⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected rat-brain paraffin-section caption does not state a fixative (A03491 caption: fixative unreported). That caption uses high-pressure retrieval in 10 mM citrate, pH 6.0, with antibody at 1:200; it does not establish a universal retrieval requirement (A03491 caption). The supplied evidence does not establish whether frozen sections or IF/ICC are easier; neuronal lipofuscin can add autofluorescent background if cerebellum is examined by IF (standard IF practice).

HPA tissue IHC evidence for SNAPIN

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — 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
Adipose tissue	Adipocytes	High	Protein (IHC)	HPA →
Adrenal gland	Glandular cells	High	Protein (IHC)	HPA →
Bone marrow	Hematopoietic cells	High	Protein (IHC)	HPA →
Cerebellum	Purkinje cells	High	Protein (IHC)	HPA →
Endometrium	Glandular cells	Medium	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 SNAPIN IHC Tips

Troubleshoot SNAPIN staining in paraffin sections using the catalog antibody’s retrieval condition, known subcellular locations, and tissue expression evidence (datasheet A03491; UniProt O95295; HPA tissue IHC).

Which retrieval condition should I start with for SNAPIN in paraffin sections?

Start with heat-mediated retrieval in 10 mM citrate buffer at pH 6.0 before chromogenic IHC (datasheet A03491). The rat brain paraffin-section image used high-pressure retrieval under that condition and a 1:200 primary antibody dilution; its caption does not report the fixative (datasheet A03491). If staining is weak, compare a shorter and longer heating time on adjacent sections while keeping buffer and detection conditions constant (standard IHC practice). Include a section processed without primary antibody, and check whether stronger retrieval increases diffuse staining or damages section structure (standard IHC practice).

How should I troubleshoot weak SNAPIN staining when fixation history is uncertain?

Target-specific sensitivity of SNAPIN staining to fixation is unknown from the supplied evidence; the catalog image identifies paraffin sections but does not state a fixative (datasheet A03491). Record the specimen’s fixative and fixation duration when available, then compare sections with similar processing histories before changing antibody concentration (standard IHC practice). Use the specified citrate retrieval condition as the starting point and assess morphology alongside signal after any retrieval adjustment (datasheet A03491; standard IHC practice). Do not attribute weak staining to a particular fixation-induced SNAPIN epitope change without a controlled comparison using the same antibody (standard IHC practice).

What staining pattern should count as plausible SNAPIN localisation in tissue?

Evaluate SNAPIN mainly as cytoplasmic staining in tissue, while allowing punctate or perinuclear accentuation consistent with its annotated Golgi, vesicle, and lysosome associations (HPA tissue IHC: general cytoplasmic expression; UniProt O95295 subcellular location). SNAPIN has no annotated transmembrane segment, so a sharply outlined cell-surface-only pattern warrants scrutiny (UniProt O95295 topology). Compare cell bodies and nearby background at the same magnification, preserving the counterstain so intracellular signal can be assigned to cells (standard IHC practice). HPA reports approved Golgi localisation in cell imaging but uncertain nucleolar localisation; isolated nuclear staining should therefore be checked against controls before interpretation (HPA subcellular).

Could isoforms or epitope masking explain a changed SNAPIN IHC pattern?

The supplied UniProt record lists 0 isoforms, so an isoform-specific explanation is unsupported here (UniProt O95295 isoforms). SNAPIN has no annotated transmembrane segment and includes reported phosphorylation sites, but the supplied evidence does not map this antibody’s epitope or establish how those modifications affect its IHC binding (UniProt O95295 topology and modified residues; datasheet A03491). Compare staining after the specified citrate retrieval across matched sections before assigning a molecular explanation to signal loss (datasheet A03491; standard IHC practice). If epitope dependence matters, seek antibody-specific epitope information and validate the proposed effect with appropriate controls (standard IHC practice).

How can I check an IHC localisation finding by multiplex immunofluorescence?

Use IF as a separate validation experiment and pair SNAPIN with a marker identifying the cell population being examined, such as a macrophage marker when investigating lung macrophages (HPA tissue IHC: High in lung macrophages; standard IF practice). Choose fluorophores after measuring tissue autofluorescence, favoring channels with clearer separation from that background (standard IF practice). Because SNAPIN is annotated in the cytosol and on intracellular organelle membranes without a transmembrane segment, pilot permeabilisation that permits access to intracellular epitopes while retaining cell structure (UniProt O95295 subcellular location and topology; standard IF practice). Include single-label and no-primary controls when evaluating apparent colocalisation (standard IF practice).

How do I distinguish SNAPIN signal from chromogenic background?

Inspect no-primary and secondary-only controls for detection-system staining before interpreting a faint SNAPIN result (standard IHC practice). For peroxidase-based chromogenic detection, include a peroxidase block and evaluate DAB development time on matched sections; these are general workflow steps, not SNAPIN-specific evidence (standard IHC practice). Check whether signal follows section folds, cut edges, pigment, or tissue damage rather than intracellular cell boundaries (standard IHC practice). Compare suspect regions with an expected high-staining population and a low or undetected population, such as lung macrophages and smooth muscle cells, while accounting for tissue differences (HPA tissue IHC: High in lung macrophages; Not detected in smooth muscle cells).

How should I score SNAPIN staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and cytoplasmic compartment before scoring, then report the percentage of positive cells and an intensity-weighted H-score if intensity is reproducible (HPA tissue IHC: general cytoplasmic expression; standard IHC practice). Alternatively, report positive-cell density per mm² when cell abundance itself is the outcome (standard IHC practice). Normalize counts to viable tissue area or the relevant cell population, and apply identical retrieval, imaging, and scoring thresholds across sections (standard IHC practice). Exclude folds, damaged edges, and necrotic regions using a prespecified rule, and retain representative negative-control images for threshold review (standard IHC practice).

When should I doubt an apparent SNAPIN-positive cell or region?

A convincing result should show intracellular staining in identifiable cells and agree with controls; HPA describes general cytoplasmic tissue expression, with high staining in several populations including Purkinje cells (HPA tissue IHC: general cytoplasmic expression; High in Purkinje cells; standard IHC practice). Question an exclusively cell-surface pattern because SNAPIN lacks an annotated transmembrane segment (UniProt O95295 topology). Treat signal confined to cut edges, necrotic tissue, or no-primary controls as possible artefact, and check peroxidase-related background when using DAB (standard IHC practice). HPA rates its tissue staining Approved while noting medium agreement with RNA and pending external verification, so corroborate surprising cell assignments independently (HPA tissue IHC reliability).

Boster reagents

Best SNAPIN / SNARE-associated protein Snapin IHC Antibodies

A03491 has real IHC images from paraffin-embedded rat brain and kidney (catalog IHC image captions). Its listed reactivity is Human, Mouse, and Rat (catalog: reactivity); no IF images are provided (catalog: IF image alts).

Real IHC data Immunohistochemistry of paraffin-embedded rat brain using SNAPIN Rabbit pAb at dilution of 1:200 .Perform high pressure antigen retrieval with 10 mM citrate buffer pH 6.0 before commencing with IHC staining protocol.

Anti-SNAPIN Antibody

Cat # A03491

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A03491 will render with its rat brain IHC figure (catalog: IHC image caption). A second caption documents paraffin-embedded rat kidney staining; the listed applications are IHC and WB (catalog: IHC image captions; applications).

Which to pick: Choose A03491 for paraffin-section tissue IHC: it is a rabbit polyclonal antibody with rat brain and kidney staining shown at 1:200 after citrate pH 6.0 retrieval (catalog: host; IHC image captions). Its listed Human, Mouse, and Rat reactivity supports cross-species selection, although the supplied IHC images show rat tissue only (catalog: reactivity; IHC image captions). No IF/ICC-validated SKU is supplied here (catalog: applications; IF image alts); the IHC captions report paraffin embedding but do not report the fixative (catalog: IHC image captions).

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

References

UniProt Consortium. UniProt entry O95295 (SNAPN_HUMAN, SNARE-associated protein Snapin).
Human Protein Atlas. SNAPIN tissue IHC expression (reliability: Approved).
Human Protein Atlas. SNAPIN subcellular location (ICC-IF): Mainly localized to the Golgi apparatus. In addition localized to the nucleoli..
Human Protein Atlas. SNAPIN antibody validation summary (1 antibodies).
SNAPIN Regulates Cell Cycle Progression to Promote Pancreatic β Cell Growth. Frontiers in endocrinology 2021 — PMC8237857.
SNAPIN Facilitates Progression of Hepatocellular Carcinoma by Hindering Ferroptosis Through KEAP1 Degradation Promotion. Cancer science 2026 — PMC12775592.
CK1δ-Dependent SNAPIN Dysregulation Drives Lysosomal Failure in HIV-1 Vpr-Exposed Neurons: A Targetable Mechanism in HAND. bioRxiv : the preprint server for biology 2025 — PMC12338511.
Snapin deficiency is associated with developmental defects of the central nervous system. Bioscience reports 2011 — PMC4957243.
PubMed PMID:10195194 — UniProt-cited evidence.
PubMed PMID:14702039 — UniProt-cited evidence.
PubMed PMID:16710414 — UniProt-cited evidence.