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PACS1 / Phosphofurin acidic cluster sorting protein 1 · IHC design guide
Design Immunohistochemistry for PACS1
Plan PACS1 chromogenic IHC on paraffin sections using the catalog antibody at a starting concentration of 2 μg/mL (datasheet). Compare cytoplasmic staining with the tissue profile (HPA tissue IHC); perinuclear trans-Golgi localisation is a molecular expectation (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PACS1 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 tissue staining (HPA tissue IHC) | |
| Staining pattern | General cytoplasmic staining, abundant in lymphoid tissue (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Breast+4 more · see all | |
| Negative control | Liver |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep formalin fixation consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | Antibody staining and RNA show medium consistency (HPA tissue IHC) | |
| Regulation | No specific expression regulator annotated (UniProt) | |
| Isoform / epitope | 2 isoforms; epitope coverage needs checking (UniProt) |
Section 1
Recommended PACS1 IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol with the published PACS1 staining method for gastric tissue microarrays (PMC5906598).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet A06811-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat-induced epitope retrieval in citrate buffer, pH 6.0, 20 min at 95–98 °C (standard rule: cytoplasmic / membrane antigen) |
| 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-PACS1, 2 μg/mL (datasheet A06811-1) |
| 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 | PACS1-positive staining in glandular cells of breast (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression, highly abundant in lymphoid tissues. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 HIER at 95–98 °C for 20 min (page retrieval); the article specifies high-pressure retrieval without buffer details (PMC5906598).
Section 2
What Is the Expected PACS1 Staining Pattern?
PACS1 is associated with the trans-Golgi network and perinuclear region, with no transmembrane segment (UniProt Q6VY07). In paraffin-section IHC, expect cytoplasmic staining in several cell types, including breast glandular and neuronal cells; lymphoid tissues are described as highly abundant (HPA tissue IHC). The tissue staining profile is Approved, with medium consistency between staining and RNA data (HPA tissue IHC).
| Cytoplasmic staining in breast glandular cells or cerebral cortex neurons, possibly enriched near the nucleus. | These cells are reported High by tissue IHC (HPA tissue IHC). Perinuclear enrichment is compatible with the trans-Golgi network location, but is not required to call every positive cell (UniProt Q6VY07). |
| Strong nuclear-only staining, with little cytoplasmic staining, dominates a paraffin section. | This differs from the general cytoplasmic tissue IHC profile (HPA tissue IHC). Treat it as a possible artefact and check controls before scoring it as PACS1; HPA calls nucleoplasmic ICC-IF localization uncertain (HPA subcellular). |
| Liver cholangiocytes stain as strongly as the expected positive cells. | Cholangiocytes are listed as Not detected (HPA tissue IHC). Investigate antibody cross-reactivity or endogenous detection activity before accepting this signal; the tissue profile alone cannot identify which caused it. |
| Colour covers tissue structures indiscriminately, obscuring cell boundaries and cytoplasmic detail. | This cannot be scored against the reported cell-specific staining levels (HPA tissue IHC). Background or detection artefact is possible (general IHC practice); assess a primary-antibody omission control and tissue morphology. |
| No staining appears in an adequately preserved breast glandular-cell region. | Breast glandular cells are reported High (HPA tissue IHC), so a blank result warrants an assay check. One negative section cannot establish absent PACS1: the tissue profile has only medium staining–RNA consistency (HPA tissue IHC). |
💡Expected PACS1 appearanceCall a positive result when discernible cytoplasmic signal appears in expected cells, such as High-staining breast glandular cells (HPA tissue IHC), with possible perinuclear emphasis (UniProt Q6VY07); indiscriminate colour or nuclear-only signal calls for artefact checks (general IHC practice; HPA tissue IHC).
| Tissue and cell choice | Use the named cell population when judging a section: breast glandular cells are High, whereas liver cholangiocytes are Not detected (HPA tissue IHC). A whole-tissue impression can hide that distinction. |
| IHC antibody evidence | HPA038914 is a rabbit polyclonal antibody with Approved IHC status (HPA antibodies). The supplied record does not label its IHC result Enhanced (HPA antibodies); interpret unusual staining with controls and morphology. |
| Protein form and location | UniProt lists two isoforms, no transmembrane segment, no signal peptide and no annotated glycosylation sites (UniProt Q6VY07). These annotations do not establish which isoform an antibody detects or predict a section's staining intensity. |
| Fixation and retrieval | Target-specific fixation sensitivity and retrieval response are unreported in the supplied UniProt and HPA records. Follow the validated IHC procedure and compare control sections (general IHC practice); do not infer a PACS1-specific fixation effect. |
| IF/ICC Q: Should its location match IHC? | A: HPA's ICC-IF main location is plasma membrane, with approved vesicular and uncertain nucleoplasmic localization (HPA subcellular). Tissue IHC is described as generally cytoplasmic (HPA tissue IHC); assess IF/ICC on its own guide page. |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected positive cells remain blank. | An assay or detection failure is possible; breast glandular cells are reported High (HPA tissue IHC). A blank result does not by itself identify the failed step. | Check tissue preservation, the IHC antibody procedure, reagent activity and a known-positive control in the same run (general IHC practice). Do not assign a PACS1-specific fixation cause. |
| Signal is faint or varies across expected positive cells. | The tissue profile has medium staining–RNA consistency (HPA tissue IHC); variation alone does not establish antibody failure or a biological difference. | Compare the same named cell type across sections and runs, then score intensity only where morphology and control staining are interpretable (general IHC practice). |
| Nuclear-only staining dominates the slide. | The pattern differs from general cytoplasmic tissue staining (HPA tissue IHC). HPA marks nucleoplasmic ICC-IF localization uncertain (HPA subcellular). | Compare cytoplasmic signal in expected positive cells and examine a primary-antibody omission control before assigning PACS1 positivity (general IHC practice). |
| Cholangiocytes appear positive. | They are reported Not detected (HPA tissue IHC). Cross-reactivity or endogenous chromogenic detection activity could account for unexpected colour (general IHC practice). | Check a primary-antibody omission control and the detection system's endogenous-activity controls, then compare with an expected positive cell population (general IHC practice). |
| Diffuse colour obscures cell-specific staining. | Background from antibody concentration, incomplete washing or detection chemistry is possible (general IHC practice); the image cannot support reliable cell-level scoring. | Review omission controls, washing and antibody concentration within the validated IHC procedure; score only sections where cellular detail remains visible (general IHC practice). |
| Membrane-heavy staining raises doubt about the IHC result. | HPA reports approved plasma-membrane localization by ICC-IF, while describing tissue IHC as generally cytoplasmic (HPA subcellular; HPA tissue IHC). Assay context matters. | Compare membrane and cytoplasmic staining in the named positive cell type and inspect omission controls. Record the observed pattern without treating the ICC-IF image as a paraffin-IHC reference (general IHC practice; HPA tissue IHC). |
Experiment evidence
IHC & IF images showing PACS1 staining
A06811-1 · IHCImmunohistochemistry of PACS1 in mouse brain tissue with PACS1 antibody at 2 μg/ml.
A06811-1 · IFImmunofluorescence of PACS1 in human bladder tissue with PACS1 antibody at 20 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000175115-PACS1/tissue/cerebral+cortex#imid_10069660
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000175115-PACS1/tissue/colon#imid_10069578
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000175115-PACS1/tissue/liver#imid_10069579
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000175115-PACS1/tissue/kidney#imid_10069572
HPA · ICC-IF MCF-7Human Protein Atlas immunofluorescence, MCF-7, antibody HPA075046; green = PACS1, blue = nucleus, red = microtubules.
HPA · ICC-IF MCF-7Human Protein Atlas immunofluorescence, MCF-7, antibody HPA075046; green = PACS1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PACS1 IHC & IF
🧪Run breast first: its glandular cells must stain (HPA: High in breast glandular cells). Run liver cholangiocytes as the negative tissue (HPA: Not detected in liver cholangiocytes); cells without specific signal on the breast slide should show only background chromogen, although HPA does not identify a negative cell type within breast (HPA: breast glandular-cell row).
Positive control tissue: Breast (Glandular cells, HPA High)
Negative control tissue: Liver (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PACS1 in MCF-7, SiHa, U2OS, KOLF2.1J, with annotated localisation: Plasma membrane (approved) (HPA subcellular).
Technical controls: Include no-primary (secondary-only) and host- and isotype-matched irrelevant IgG controls, matched to the primary antibody’s clonality, plus PACS1-knockout tissue or a validated peptide-block control (standard IHC practice). Quench endogenous peroxidase for chromogenic IHC, block endogenous biotin if using avidin–biotin detection, and check breast-tissue autofluorescence for IF (standard IHC/IF practice).
⚠️Feasibility: A target-specific fixation window and antigen-retrieval dependence are unreported in the supplied PACS1 evidence; the A06811-1 mouse-brain IHC caption also leaves the fixative unreported (selected SKU caption). These data do not establish whether frozen sections or IF are easier (supplied PACS1 evidence). For breast, assess glandular background and, if using IF, tissue autofluorescence alongside specific staining (standard IHC/IF practice).
HPA tissue IHC evidence for PACS1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Medium 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 |
|---|---|---|---|---|
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Caudate | Neuronal cells | High | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | High | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | High | Protein (IHC) | HPA → |
| Endometrium | Glandular cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Liver | Cholangiocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced PACS1 IHC Tips
Troubleshooting PACS1 staining in paraffin sections requires attention to retrieval, compartment pattern, tissue controls and consistent scoring.
How should I retrieve PACS1 antigen when staining paraffin sections?
Use citrate buffer at pH 6.0 for heat-induced retrieval at 95–98 °C for 20 minutes (page retrieval rule). Keep section thickness, heating vessel and cooling time consistent across runs so differences in staining can be assessed against the same retrieval conditions (standard IHC practice). If staining is weak, first check deparaffinisation and the positive control before extending heating; excessive retrieval can damage morphology and increase background (standard IHC practice). The catalog antibody has a mouse brain tissue-IHC image at 2 µg/ml, but its caption does not state the fixative or retrieval method (catalog caption: A06811-1).
Could fixation explain weak or uneven PACS1 staining in my sections?
PACS1-specific fixation sensitivity is unknown from the supplied evidence; the selected tissue-IHC caption does not state a fixative (catalog caption: A06811-1). Record fixative, fixation duration and processing conditions for each specimen, then compare sections processed together before changing antibody concentration (standard IHC practice). Underfixation can impair morphology, while prolonged fixation can mask epitopes; neither effect has been demonstrated specifically for PACS1 here (standard IHC practice). Use the stated citrate pH 6.0, 95–98 °C, 20-minute retrieval as a consistent starting point, and evaluate changes against a concurrently stained positive control (page retrieval rule; standard IHC practice).
What PACS1 staining pattern should I expect in chromogenic IHC?
Look for cytoplasmic staining with possible perinuclear enrichment: PACS1 is reported at the Golgi and probably the trans-Golgi network, while tissue IHC shows general cytoplasmic expression (UniProt Q6VY07 localisation; HPA tissue IHC). PACS1 has no annotated transmembrane segment, so a purely sharp membrane rim warrants closer scrutiny rather than automatic acceptance (UniProt Q6VY07 topology; standard IHC interpretation). The subcellular IF record also reports approved plasma-membrane and vesicle localisation, which can differ from the appearance of chromogenic tissue staining (HPA subcellular). Compare the pattern within intact cells and against a no-primary control; diffuse staining over damaged areas alone is insufficient evidence of localisation (standard IHC practice).
How can isoforms or epitope accessibility affect PACS1 IHC?
PACS1 has two annotated isoforms, but the supplied catalog caption does not identify the antibody epitope or establish which isoforms it detects (UniProt Q6VY07 isoforms; catalog caption: A06811-1). Check the antibody's documented immunogen against isoform sequences before interpreting absent staining as absence of all PACS1 protein (standard antibody validation practice). PACS1 has annotated phosphorylation sites, including residues 28, 46, 251 and 379; no supplied evidence links those modifications to this antibody's staining (UniProt Q6VY07 modified residues). If staining changes after processing, compare matched sections under identical retrieval and detection conditions before proposing an isoform or modification-specific explanation (standard IHC practice).
How can IF help assess an ambiguous PACS1 IHC pattern?
Use IF as a separate localisation check and multiplex PACS1 with a marker for the cell type being evaluated, such as a neuronal marker when investigating the reported neuronal staining in caudate or cerebral cortex (HPA tissue IHC; standard IF practice). Choose fluorophores and imaging channels after inspecting unstained tissue autofluorescence, particularly when a dim PACS1 signal could overlap with it (standard IF practice). For intracellular PACS1, permeabilise sufficiently to reach the cytoplasmic epitope; if the antibody epitope is unknown, compare permeabilised and non-permeabilised preparations before interpreting surface signal (UniProt Q6VY07 localisation; standard IF practice). The HPA IF record reports plasma-membrane and vesicle localisation, but those observations do not specify conditions for this catalog antibody (HPA subcellular).
How do I reduce background without losing PACS1 signal?
Start by comparing a no-primary section with the PACS1-stained section to identify secondary-reagent and detection background (standard IHC practice). Block endogenous peroxidase before chromogenic detection, use an appropriate protein block, and wash thoroughly between antibody and detection steps (standard IHC practice). Titrate the primary antibody on a positive control; the catalog mouse brain caption reports 2 µg/ml for its tissue image, without establishing an optimal concentration for every specimen (catalog caption: A06811-1). If diffuse staining persists, check section drying, incomplete deparaffinisation and excessive retrieval while retaining the same exposure and DAB development conditions for comparisons (standard IHC practice).
How should I quantify PACS1 staining across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define the tissue compartment and eligible intact cells before scoring, because PACS1 tissue staining is described as broadly cytoplasmic and abundant in lymphoid tissues (HPA tissue IHC; standard IHC practice). For cell-based comparison, record the percentage of positive cells and staining intensity, or calculate an H-score from intensity categories 0–3 using one prespecified threshold (standard IHC scoring practice). For spatial comparisons, report positive-cell density per mm² of viable tissue rather than per whole image (standard IHC scoring practice). Normalise acquisition, DAB development and scoring to concurrently processed controls, and report the analysed viable area or eligible cell count for each specimen (standard IHC practice).
When is PACS1 staining convincing rather than an artefact?
A convincing result places signal in intact, identifiable cells and is compatible with reported cytoplasmic or perinuclear PACS1 staining, while allowing for the plasma-membrane and vesicle observations from IF (HPA tissue IHC; UniProt Q6VY07 localisation; HPA subcellular). Use cell identity and a concurrently stained positive control: HPA reports high neuronal staining in caudate and cerebral cortex, but its tissue-IHC reliability is rated Approved with medium RNA–staining consistency (HPA tissue IHC). Be cautious with staining confined to section edges, necrotic regions or areas of poor morphology (standard IHC interpretation). Exclude endogenous peroxidase or nonspecific detection signal with appropriate controls before assigning DAB deposits to PACS1 (standard IHC practice).
Boster reagents
Best PACS1 / Phosphofurin acidic cluster sorting protein 1 IHC Antibodies
A06811-1 has IHC-P and IF applications (catalog: applications), with mouse brain IHC and mouse brain and human bladder IF images (catalog: image captions). Human, mouse and rat are listed as reactive (catalog: reactivity).
Real IHC data
Anti-PACS1 Antibody
Cat # A06811-1
A06811-1 will render with an IHC image of mouse brain tissue stained at 2 μg/mL (catalog: IHC image caption). Its IF images show human bladder tissue and mouse brain tissue at 20 μg/mL (catalog: IF image captions).
Which to pick: Choose A06811-1 for tissue IHC-P: its application list includes IHC-P, and its own IHC caption shows mouse brain tissue at 2 μg/mL; the fixative is unreported (catalog: applications; IHC image caption). For IF, A06811-1 has human bladder and mouse brain tissue images; ICC is not listed as a tested application (catalog: IF image captions; applications). For work across species, A06811-1 lists human, mouse and rat reactivity, while its supplied IHC image documents mouse tissue only (catalog: reactivity; IHC image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q6VY07 (PACS1_HUMAN, Phosphofurin acidic cluster sorting protein 1).
- Human Protein Atlas. PACS1 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. PACS1 subcellular location (ICC-IF): Mainly localized to the plasma membrane. In addition localized to the nucleoplasm and vesicles..
- Human Protein Atlas. PACS1 antibody validation summary (2 antibodies).
- iPSC-derived models of PACS1 syndrome reveal transcriptional and functional deficits in neuron activity. Nature communications 2024 — PMC10821916.
- Down-regulation of a pro-apoptotic pathway regulated by PCAF/ADA3 in early stage gastric cancer. Cell death & disease 2018 — PMC5906598.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:10574461 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PACS1 (Phosphofurin acidic cluster sorting protein 1). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A06811-1 at 2 μg/mL (the product's own IHC validation image is shown). Controls (HPA): positive Breast (Glandular cells); negative Liver. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet A06811-1); 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-induced epitope retrieval in citrate buffer, pH 6.0 , 20 min at 95–98 °C…; 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-PACS1, 2 μg/mL (datasheet A06811-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep formalin fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Antibody staining and RNA show medium consistency (HPA tissue IHC); Isoform / epitope: 2 isoforms; epitope coverage needs checking (UniProt); Regulation: No specific expression regulator annotated (UniProt). Evidence: UniProt Q6VY07, HPA tissue IHC · Approved, HPA ICC-IF · Mainly localized to the plasma membrane. In addition localized to…, Datasheet A06811-1, PMC5906598. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PACS1/immunohistochemistry-ihc-guide.