PICALM / Phosphatidylinositol-binding clathrin assembly protein · IHC design guide

Design Immunohistochemistry for PICALM

Plan PICALM staining in paraffin sections with the catalog antibody’s documented chromogenic IHC workflow (datasheet A02053-1). Compare cytoplasmic and membranous staining across cell types using the tissue IHC profile (HPA tissue IHC).

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

Immunohistochemistry protocol sheet for PICALM (IHC for PICALM): expected localisation Cytoplasmic and membranous tissue staining (HPA tissue IHC), antibody A02053-1, validated IHC image, and IHC protocol steps — Printable **PICALM** IHC protocol sheet — expected localisation Cytoplasmic and membranous tissue staining (HPA tissue IHC), antibody A02053-1, controls and protocol steps. Open the full PICALM IHC guide →

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PICALM 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	Cytoplasmic/membranous in glandular and endocrine cells (HPA tissue IHC)
	Antigen retrieval	EDTA pH 8.0 HIER, heat-mediated (datasheet A02053-1)
	Positive control ⓘ	Adrenal gland+4 more · see all
	Negative control ⓘ	Skeletal muscle+1 more · see all

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	Myocytes may be negative despite broad tissue staining (HPA tissue IHC)
	Regulation	Specific expression regulation is not reported (UniProt)
	Isoform / epitope	5 isoforms; check antibody epitope coverage (UniProt)

Section 1

Recommended PICALM IHC & IF Protocols

The catalog antibody’s IHC-P protocol (datasheet A02053-1) is accompanied by 4 published PICALM IHC protocols (PMC4148152; PMC3949918; PMC9063212; PMC4482781).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human Ovarian cancer tissue; fixative not specified (datasheet A02053-1)
Fixation	Image fixative and duration unreported (datasheet A02053-1); verify before use.
Sectioning	4–5 µm sections on charged slides (standard)
Deparaffinisation	Xylene, graded ethanol series to water (standard)
Antigen retrieval	Heat retrieval: EDTA pH 8.0 (datasheet A02053-1); 20 min, 95–100 °C (standard)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% goat serum (datasheet A02053-1)
Primary antibody	Rabbit anti-PICALM, 0.5-1μg/ml (datasheet A02053-1)
Primary incubation	Overnight at 4 °C (datasheet A02053-1)
Detection	Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A02053-1)
Counterstain	Hematoxylin, blue, dehydrate and mount (standard)
Expected result	PICALM-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Ubiquitous cytoplasmic and membranous expression, most abundant in gastrointestinal tract, kidney and placenta. No signal in the no-primary control.

💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 (datasheet A02053-1); citrate at pH 6.0 is a published alternative (PMC4148152; PMC3949918).

Section 2

What Is the Expected PICALM Staining Pattern?

PICALM should show predominantly cytoplasmic and membranous staining in paraffin tissue sections, with vesicle-associated signal compatible with its role at clathrin-coated pits and vesicles (HPA tissue IHC; UniProt Q13492). High staining is reported in selected glandular and endocrine cells, while skeletal and smooth muscle cells are reported as not detected (HPA tissue IHC). HPA rates its tissue IHC evidence “Enhanced,” with medium consistency between staining and RNA expression (HPA tissue IHC).

What am I looking at on my slide?
Cytoplasmic and membranous staining is strong in adrenal or breast glandular cells, or in appendix, colon, or duodenal endocrine cells (HPA tissue IHC).	This fits the reported high staining in those cells (HPA tissue IHC). Punctate signal within the cytoplasm is also plausible for a protein associated with clathrin-coated vesicles (UniProt Q13492). Judge intensity against matched controls rather than requiring every cell in the section to stain equally (standard IHC practice).
Staining appears exclusively nuclear, with no convincing cytoplasmic or membranous component.	Review compartment assignment and staining specificity: the usual tissue pattern is cytoplasmic and membranous (HPA tissue IHC). Nuclear PICALM is possible in some cells, potentially through interaction with PIMREG, so nuclear signal alone is not proof of an artefact (UniProt Q13492).
Skeletal myocytes or smooth muscle cells stain as strongly as a known-positive glandular or endocrine population.	That distribution conflicts with the HPA entries reporting those muscle cells as not detected (HPA tissue IHC). Consider nonspecific antibody binding or endogenous chromogen-generating activity; compare with a primary-antibody omission control and a known-positive section (standard IHC practice).
Brown colour is diffuse across cells and extracellular areas, without a discernible cytoplasmic or membranous pattern.	This is difficult to assign to PICALM, whose reported tissue pattern is cytoplasmic and membranous (HPA tissue IHC). Examine the no-primary control for detection-system background, then reassess blocking, washes, and antibody concentration (standard IHC practice).
A section containing a reported high-staining population shows no signal.	First verify that the expected cells are present: HPA reports high staining in selected glandular and endocrine populations, not uniformly across each tissue (HPA tissue IHC). If they are present, check the positive control, antibody preparation, retrieval, and detection steps (standard IHC practice).

💡Expected PICALM appearanceCall a result positive when identifiable glandular or endocrine cells show convincing cytoplasmic and membranous staining, potentially punctate, at an intensity above matched background; uniform extracellular colour or equally strong muscle-cell staining is suspect (HPA tissue IHC; UniProt Q13492; standard IHC practice).

How each factor affects the staining
Cell population and tissue	PICALM has low tissue specificity, yet individual cell populations differ: selected glandular and endocrine cells are high, some glia and squamous epithelia are low, and listed muscle cells are not detected (HPA tissue IHC). Select and score the specific cell population, rather than treating the whole organ as uniformly positive (standard IHC practice).
Subcellular distribution	PICALM has no transmembrane segment and is associated with the cell membrane, clathrin-coated pits and vesicles, Golgi apparatus, and sometimes the nucleus (UniProt Q13492). A cytoplasmic or membranous IHC pattern is therefore more informative than expecting a continuous membrane outline (HPA tissue IHC; UniProt Q13492).
Evidence and antibody validation	HPA rates tissue IHC reliability “Enhanced” but reports only medium consistency between staining and RNA expression (HPA tissue IHC). Two listed rabbit polyclonal antibodies, HPA019053 and HPA019061, each have Enhanced IHC validation (HPA antibodies). Interpret an unexpected cell pattern with controls rather than treating the rating as proof for every specimen (standard IHC practice).
Isoforms and epitope coverage	UniProt lists five PICALM isoforms and an ENTH domain at residues 14–145 (UniProt Q13492). The supplied record gives no antibody epitope, so it cannot establish which isoforms the catalog antibody detects or predict how a particular retrieval condition affects staining.
IF/ICC Q&A: What pattern should be expected?	HPA reports an enhanced vesicle localization in ICC-IF images from A-431, U-251MG, U2OS, and NIH 3T3 cells (HPA subcellular; HPA antibodies). That observation can inform compartment interpretation, but the paraffin-section IHC tissue pattern remains the basis for calling this guide’s IHC result (HPA tissue IHC).

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
No staining in a section expected to contain high PICALM expression.	The scored cells may be absent, or an IHC workflow step may have failed; HPA assigns high staining to specified cell populations within tissues (HPA tissue IHC).	Confirm the target cells morphologically, then run a reported high-staining population as a positive control and check reagent preparation, retrieval, and detection (HPA tissue IHC; standard IHC practice).
Strong colour in skeletal myocytes or smooth muscle cells.	These populations are reported as not detected, making nonspecific staining or endogenous detection activity possible explanations (HPA tissue IHC; standard IHC practice).	Compare a no-primary control, assess the relevant endogenous-activity block, and review antibody concentration before assigning positivity (standard IHC practice).
Diffuse colour obscures cell boundaries.	Widespread background prevents confident recognition of the reported cytoplasmic and membranous pattern (HPA tissue IHC).	Check the no-primary section; optimize blocking and washes, and adjust antibody or detection-reagent concentration if background persists (standard IHC practice).
Signal appears only in nuclei.	Nuclear localization can occur in some cells, but an exclusively nuclear result differs from the usual tissue IHC pattern (UniProt Q13492; HPA tissue IHC).	Recheck morphology and controls, and compare another positive tissue population before classifying the nuclear signal as PICALM or artefact (standard IHC practice).
Signal is weak in glia or squamous epithelium.	HPA lists low staining in selected glial and squamous epithelial populations (HPA tissue IHC).	Use a reported high-staining glandular or endocrine population to verify assay performance before interpreting weak staining in a low-expression population (HPA tissue IHC; standard IHC practice).
A tissue gives mixed positive and negative cells.	HPA reports PICALM staining by cell type, and its tissue IHC evidence has medium consistency with RNA expression (HPA tissue IHC).	Score the identified cell population and its compartment separately; compare the pattern with a matched control instead of assigning one result to the whole section (HPA tissue IHC; standard IHC practice).

Source: UniProt Q13492 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing PICALM staining

IHC analysis of PICALM using anti-PICALM antibody (A02053-1). PICALM was detected in paraffin-embedded section of human Ovarian cancer tissue. Heat mediated antigen retrieval was performed in EDTA buffer (pH8.0, epitope retrieval solution). The tissue section was blocked with 10% goat serum. The tissue section was then incubated with 1μg/ml rabbit anti-PICALM Antibody (A02053-1) 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.

A02053-1 · IHCIHC analysis of PICALM using anti-PICALM antibody (A02053-1). PICALM was detected in paraffin-embedded section of human Ovarian cancer tissu

IF analysis of PICALM using anti-PICALM antibody (A02053-1). PICALM was detected in immunocytochemical section of A431 cells. Enzyme antigen retrieval was performed using IHC enzyme antigen retrieval reagent (AR0022) for 15 mins. The cells were blocked with 10% goat serum. And then incubated with 2μg/mL rabbit anti-PICALM Antibody (A02053-1) overnight at 4°C. DyLight®488 conjugated Goat Anti-Rabbit IgG (BA1127) was used as secondary antibody at 1:100 dilution and incubated for 30 minutes at 37°C. The section was counterstained with DAPI. Visualize using a fluorescence microscope and filter sets appropriate for the label used.

A02053-1 · IFIF analysis of PICALM using anti-PICALM antibody (A02053-1). PICALM was detected in immunocytochemical section of A431 cells. Enzyme antigen

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000073921-PICALM/tissue/cerebral+cortex#imid_5329008

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000073921-PICALM/tissue/colon#imid_5328950

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000073921-PICALM/tissue/liver#imid_5328943

HPA · PancreasHuman Protein Atlas IHC, Pancreas. Source: https://www.proteinatlas.org/ENSG00000073921-PICALM/tissue/pancreas#imid_5328886

HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA019053; green = PICALM, blue = nucleus, red = microtubules.

← swipe / scroll for more images →

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

Sample controls for PICALM IHC & IF

🧪Run breast first and expect staining in glandular cells (HPA: High in breast glandular cells); use skeletal muscle myocytes as the negative tissue (HPA: Not detected in skeletal muscle myocytes). On the breast slide, assess cells outside the glandular compartment for background staining, without assuming they are PICALM-negative (UniProt Q13492: expressed in all tissues examined).

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

Negative control tissue: Skeletal muscle (HPA Not detected)

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PICALM in A-431, U-251MG, U2OS, NIH 3T3, with annotated localisation: Vesicles (enhanced) (HPA subcellular).

Technical controls: Include a no-primary, secondary-only control and a host-matched rabbit IgG isotype control (hero IHC caption: rabbit anti-PICALM); confirm specificity with a PICALM knockout sample or immunizing-peptide competition if available (standard IHC practice). For chromogenic detection, block endogenous peroxidase and check for endogenous biotin when using the caption’s streptavidin–biotin system (hero IHC caption: SABC with DAB; standard IHC practice).

⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A02053-1 paraffin-section caption does not report a fixative (hero IHC caption: fixative not stated). The caption uses heat-mediated retrieval in EDTA at pH 8.0, but does not establish whether retrieval is required (hero IHC caption: EDTA retrieval). No matched evidence establishes that frozen sections or IF are easier for breast tissue, or identifies a breast-specific artifact; HPA ICC-IF reports vesicular localization in cell lines (HPA: vesicles, enhanced).

HPA tissue IHC evidence for PICALM

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — 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
Adrenal gland	Glandular cells	High	Protein (IHC)	HPA →
Appendix	Endocrine cells	High	Protein (IHC)	HPA →
Breast	Glandular cells	High	Protein (IHC)	HPA →
Colon	Endocrine cells	High	Protein (IHC)	HPA →
Duodenum	Endocrine cells	High	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
Skeletal muscle	Myocytes	Not detected	Protein (IHC)	HPA →
Smooth muscle	Smooth muscle cells	Not detected	Protein (IHC)	HPA →

Section 3

Advanced PICALM IHC Tips

Troubleshoot PICALM staining in paraffin sections by checking retrieval, cellular distribution, controls and scoring before interpreting changes in signal.

Which retrieval condition should I try first for weak PICALM staining?

Start with heat mediated antigen retrieval in EDTA buffer at pH 8.0 for paraffin sections (datasheet A02053-1). The catalog antibody produced chromogenic PICALM staining after this retrieval, followed by 1 μg/mL primary antibody overnight at 4°C (datasheet A02053-1). If staining is weak, check that sections were fully deparaffinised and that the retrieval bath reached its intended temperature throughout the run (standard IHC practice). Compare any revised heating time with the original condition on adjacent sections, because excessive heating can damage morphology and complicate scoring (standard IHC practice). Keep the detection and DAB development conditions matched across that comparison (standard IHC practice).

Could fixation explain weak or uneven PICALM staining?

PICALM sensitivity to fixation is unknown: the selected paraffin section caption does not report its fixative (datasheet A02053-1). Record the fixative, fixation duration, tissue thickness and processing history for each specimen before comparing staining intensity (standard IHC practice). If specimens have different histories, stain adjacent sections together using the documented EDTA pH 8.0 retrieval and 1 μg/mL primary antibody conditions (datasheet A02053-1; standard IHC practice). Examine morphology alongside signal, since damaged or poorly preserved regions can give misleading intensity differences (standard IHC practice). Do not assign a PICALM-specific fixation effect without a controlled comparison using the same antibody and tissue (standard IHC practice).

Where should I expect PICALM signal within stained cells?

Assess cytoplasmic and membranous staining first, matching the reported widespread tissue pattern (HPA: ubiquitous cytoplasmic and membranous expression). PICALM is associated with clathrin-coated pits, coated vesicles and the Golgi area, and it has no transmembrane segment (UniProt Q13492 localisation and topology). Its intracellular distribution can therefore look punctate or perimembranous rather than like a continuous cell-surface outline (UniProt Q13492 localisation; standard IHC interpretation). Nuclear localisation is reported in some cells and may relate to interaction with PIMREG, so evaluate nuclear signal against a matched control and preserved morphology (UniProt Q13492 localisation; standard IHC practice). Score each compartment separately when the pattern changes between specimens (standard IHC practice).

How could isoforms or epitope placement alter my IHC result?

PICALM has 5 reported isoforms, but the supplied antibody caption does not identify its epitope (UniProt Q13492 isoforms; datasheet A02053-1). Establish which sequence the antibody recognises before interpreting absent staining as loss of every isoform (standard IHC practice). The ENTH domain spans residues 14–145, while the C-terminal region contributes strongly to clathrin binding; an epitope in either region could support different biological interpretations (UniProt Q13492 domains and subunit). Reported phosphoserines include residues 16, 20, 303 and 315, so consider modification state only if epitope mapping supports it (UniProt Q13492 modified residues; standard IHC practice). Compare staining with an independent epitope reagent where available (standard IHC practice).

How should I investigate an unexpected PICALM pattern by multiplex IF?

Use IF as a follow-up to the chromogenic IHC pattern, with a marker identifying the cell population being assessed (standard IF practice). For glandular cells, choose a marker appropriate to that population and verify both channels independently; glandular cells show high PICALM staining in several listed tissues (HPA: breast, endometrium and fallopian tube glandular cells; standard IF practice). Choose spectrally separated fluorophores, favouring a red or far-red PICALM channel when tissue autofluorescence interferes with shorter wavelengths (standard IF practice). PICALM has no transmembrane segment and associates with the cytoplasmic side of endocytic structures, so permeabilisation should permit access to an intracellular epitope once its location is known (UniProt Q13492 topology and function; standard IF practice).

How can I distinguish diffuse background from genuine PICALM staining?

Compare test sections with a no-primary control processed through the same secondary reagent, enzyme detection and DAB steps (standard IHC practice). The selected example used 10% goat serum blocking, a biotinylated secondary antibody and DAB development; those conditions document one staining run, not the cause of background in other specimens (datasheet A02053-1). Check peroxidase blocking and, for this biotin-based detection scheme, assess endogenous biotin when the no-primary control stains (standard IHC practice). Shorten DAB development or adjust antibody concentration only while retaining a known positive control on the same run (standard IHC practice). True signal should remain cellular and compartmentally plausible (HPA: cytoplasmic and membranous expression; UniProt Q13492 localisation).

What scoring method makes PICALM IHC comparisons defensible? ⚠ ANSWER MARKED FOR VERIFICATION

Define the scored cell population and compartment before measuring PICALM, since reported staining is cytoplasmic and membranous across many tissues (HPA: tissue IHC profile; standard IHC practice). An H-score can combine the percentage of cells at intensity grades 0–3 into a 0–300 score; alternatively report percentage positive cells or positive-cell density per mm² (standard IHC practice). Normalise cell counts to the eligible, viable tissue area or the number of cells in the specified population, using identical thresholds across samples (standard IHC practice). Exclude necrotic and folded areas, and document retrieval and DAB development for every staining batch (standard IHC practice).

When is a PICALM-positive pattern convincing rather than artefactual?

A convincing result shows reproducible staining in intact cells with cytoplasmic or membranous distribution, potentially including puncta associated with endocytic structures (HPA: tissue IHC profile; UniProt Q13492 localisation). High signal in glandular cells can support a result in an appropriate tissue, while absent skeletal myocyte staining is consistent with the listed tissue observations (HPA: high in breast glandular cells; not detected in skeletal muscle myocytes). Treat signal confined to section edges, folds or necrotic regions as suspect and check a no-primary control for endogenous enzyme or detection background (standard IHC practice). Predominantly nuclear staining needs additional validation because nuclear targeting is reported only in some cells (UniProt Q13492 localisation).

Boster reagents

Best PICALM / Phosphatidylinositol-binding clathrin assembly protein IHC Antibodies

A02053-1 has human ovarian cancer paraffin-section IHC and A431 cell IF images (catalog captions). Both antibodies list human IHC and IF; A02053-1 also lists mouse and rat reactivity (catalog applications/reactivity).

Real IHC data

Anti-PICALM ® Antibody

Cat # A02053-1

View product →

A02053-1 lists human, mouse and rat IHC and human IF/ICC; its figures show human ovarian cancer paraffin sections and A431 cells (catalog applications/reactivity; IHC/IF captions). M02053 lists human IHC and IF/ICC, but has no supplied IHC or IF figure (catalog applications/reactivity; image captions).

Which to pick: For tissue IHC, choose A02053-1 when a documented paraffin-section example is useful: its caption specifies EDTA retrieval at pH 8.0 and 1 μg/ml primary antibody; the fixative is unreported (A02053-1 IHC caption). For IF/ICC, A02053-1 has an A431 cell figure at 2 μg/ml; M02053 is a human-reactive rabbit monoclonal alternative without a supplied figure (A02053-1 IF caption; M02053 catalog). For mouse or rat IHC, choose A02053-1 because those species are listed for it, while M02053 lists human only (catalog applications/reactivity).

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

References

UniProt Consortium. UniProt entry Q13492 (PICAL_HUMAN, Phosphatidylinositol-binding clathrin assembly protein).
Human Protein Atlas. PICALM tissue IHC expression (reliability: Enhanced).
Human Protein Atlas. PICALM subcellular location (ICC-IF): Localized to vesicles..
Human Protein Atlas. PICALM antibody validation summary (2 antibodies).
A single codon insertion in PICALM is associated with development of familial subvalvular aortic stenosis in Newfoundland dogs. Human genetics 2014 — PMC4148152.
Genetics of PICALM expression and Alzheimer's disease. PloS one 2014 — PMC3949918.
PICALM exerts a role in promoting CRC progression through ERK/MAPK signaling pathway. Cancer cell international 2022 — PMC9063212.
Central role for PICALM in amyloid-β blood-brain barrier transcytosis and clearance. Nature neuroscience 2015 — PMC4482781.
PubMed PMID:8643484 — UniProt-cited evidence.
PubMed PMID:14702039 — UniProt-cited evidence.
PubMed PMID:16554811 — UniProt-cited evidence.