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CPLX1 / Complexin-1 · IHC design guide
Design Immunohistochemistry for CPLX1
Plan chromogenic IHC for CPLX1 in paraffin sections using the catalog antibody’s documented assay (datasheet A05254). Compare cytoplasmic and brain synaptic staining with tissue observations, while accounting for the cross-gene staining caution (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CPLX1 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; synaptic in brain (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic staining in nervous and neuroendocrine cells; synaptic staining in brain (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A05254) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | Staining may reflect proteins from more than one gene (HPA tissue IHC) | |
| Regulation | Overexpressed in Parkinson disease substantia nigra (UniProt) | |
| Isoform / epitope | No annotated isoforms or processing; one 1–134 chain (UniProt) |
Section 1
Recommended CPLX1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is paired with two published CPLX1 staining protocols for paraffin sections (PMC6944231; PMC12283636).
| Sample | Paraffin-embedded rat brain tissue; fixative not specified (datasheet A05254) |
| Fixation | Image fixative and duration unreported (datasheet A05254); 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 A05254); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A05254) |
| Primary antibody | Rabbit anti-CPLX1, 1:50 (datasheet A05254) |
| Primary incubation | Overnight at 4 °C (datasheet A05254) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A05254) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CPLX1-positive staining in medullary cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in nervous and neuroendocrine tissues. Synaptic positivity in brain. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet A05254); the published protocols used citrate pH 6 or Tris-EDTA pH 9 (PMC6944231; PMC12283636).
Section 2
What Is the Expected CPLX1 Staining Pattern?
CPLX1 is a cytosolic protein enriched at presynaptic release sites in mature neurons; it has no transmembrane segment (UniProt O14810: localization, topology). In paraffin sections, expect cytoplasmic and synaptic staining in nervous tissue and cytoplasmic staining in neuroendocrine cells (HPA: tissue IHC). HPA rates the tissue pattern Supported, with medium consistency between staining and RNA data, and cautions that the antibodies may target proteins from multiple genes (HPA: tissue IHC reliability).
| Cytoplasmic neuronal staining with synaptic positivity in brain; strong signal in cerebellar granular layer cells or cortical neurons (HPA: tissue IHC). | This fits the observed brain pattern and CPLX1's cytosolic, presynaptic localization (HPA: tissue IHC; UniProt O14810: localization). Assess the stained cells and neuropil together; intensity alone cannot establish target identity, given HPA's multi-gene antibody caution (HPA: tissue IHC reliability). |
| Predominantly nuclear or sharply membrane-restricted staining in an otherwise interpretable section. | Those compartments do not match the reported cytosolic and presynaptic locations or the absence of a transmembrane segment (UniProt O14810: localization, topology). Treat the pattern as suspect and compare it with a known-positive tissue and detection controls before scoring it as CPLX1 (general IHC practice). |
| Strong staining in adipocytes or bronchial respiratory epithelial cells, while expected positive cells are weak or unstained. | HPA reports CPLX1 as not detected in those cell populations (HPA: adipose tissue and bronchus IHC). Consider cross-reactivity or endogenous chromogenic detection activity, especially because HPA cautions that its antibodies may recognize proteins from multiple genes (HPA: tissue IHC reliability; general IHC practice). |
| Diffuse chromogen across cells and extracellular areas, obscuring cell boundaries. | This cannot be scored confidently as the reported cytoplasmic or synaptic pattern (HPA: tissue IHC). Nonspecific antibody binding or detection background are general IHC possibilities; compare a primary-antibody omission control and review blocking, washes, antibody concentration and development time (general IHC practice). |
| No signal in cerebellar granular layer cells, cortical neurons or adrenal medullary cells. | These are HPA high-staining populations, so an absent signal warrants a technical check before a biological conclusion (HPA: cerebellum, cerebral cortex and adrenal gland IHC). Check tissue integrity, retrieval and detection performance with appropriate controls; the supplied sources do not establish CPLX1-specific fixation sensitivity (general IHC practice; HPA: tissue IHC). |
💡Expected CPLX1 appearanceCall an IHC result consistent with CPLX1 when cytoplasmic neuronal staining and brain synaptic positivity occur in the expected cells, with high staining possible in cerebellar granular layer cells, cortical neurons and adrenal medullary cells (HPA: tissue IHC; UniProt O14810: localization); isolated nuclear, membrane-only or widespread staining in HPA-negative cell populations is suspect (UniProt O14810: topology; HPA: tissue IHC).
| Compartment and tissue context | CPLX1 is cytosolic and enriched at mature neuronal release sites (UniProt O14810: localization). HPA describes cytoplasmic expression in nervous and neuroendocrine tissues and synaptic positivity in brain (HPA: tissue IHC). Interpret signal by both cell identity and compartment. |
| Choice of positive and comparison tissues | HPA reports high staining in adrenal medullary cells, cerebellar granular layer cells and cortical neurons; medium staining in hippocampal neurons and pancreatic endocrine cells; and no detection in adipocytes (HPA: tissue IHC). These observations provide context for comparing section quality and staining distribution. |
| Antibody evidence and specificity | HPA lists IHC support for HPA071191 and HPA074390 but describes medium agreement with RNA data and warns of multi-gene targeting (HPA: antibody validation; tissue IHC reliability). A plausible pattern supports interpretation; it does not by itself prove CPLX1-specific binding. |
| Retrieval and detection settings | Optimize retrieval, antibody concentration and chromogen development using known-positive tissue and appropriate detection controls (general IHC practice). The supplied HPA and UniProt evidence gives no CPLX1-specific retrieval condition or fixation-sensitivity claim; do not infer one from staining intensity. |
| IF/ICC expectation? | HPA reports mainly vesicular localization in ICC-IF, marks that location uncertain and cautions about antibodies targeting multiple genes (HPA: subcellular ICC-IF). UniProt places CPLX1 in cytosol and at presynaptic sites (UniProt O14810: localization). Assess IF/ICC on its own guide page; do not treat the uncertain vesicular label as an IHC compartment requirement. |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected positive tissue has no stain. | The detection run may have failed, or the selected conditions may be unsuitable; HPA reports high signal in the named positive populations (HPA: tissue IHC; general IHC practice). | Review tissue preservation and detection controls, then optimize retrieval and antibody concentration with a known-positive section (general IHC practice). Do not assign a CPLX1-specific fixation cause from these sources. |
| Signal appears mainly in nuclei. | Nuclear dominance conflicts with CPLX1's reported cytosolic and presynaptic localization (UniProt O14810: localization). Nonspecific staining is possible (general IHC practice). | Compare the same run's positive tissue and primary-antibody omission control; rescore only signal in the expected cells and compartments (HPA: tissue IHC; general IHC practice). |
| Broad staining appears in HPA-negative cell populations. | Cross-reactivity or endogenous detection activity is possible (general IHC practice); HPA specifically cautions about multi-gene antibody targeting (HPA: tissue IHC reliability). | Check a matched negative tissue, a primary-antibody omission control and the detection system before calling the signal CPLX1 (HPA: tissue IHC; general IHC practice). |
| Diffuse background hides synaptic detail. | Excess antibody, incomplete blocking or washing, or overdevelopment can obscure localized chromogen in IHC (general IHC practice). | Review the omission control, reduce background through routine blocking and wash optimization, and adjust antibody concentration or development time while retaining positive-tissue signal (general IHC practice). |
| Pancreatic endocrine staining is weaker than cortical neuronal staining. | That difference can agree with HPA's medium pancreatic endocrine and high cortical neuronal levels (HPA: pancreas and cerebral cortex IHC). | Compare like cell populations within each tissue and retain a high-staining positive control; do not call a medium-staining population negative solely because it is weaker (HPA: tissue IHC; general IHC practice). |
| ICC-IF shows puncta that do not resemble the chromogenic section. | HPA's ICC-IF vesicular assignment is uncertain and carries a multi-gene targeting caution; brain IHC instead reports synaptic positivity (HPA: subcellular ICC-IF; tissue IHC). | Judge the paraffin IHC section against its tissue and cell pattern, and evaluate the ICC-IF image under the separate IF/ICC guide (HPA: tissue IHC; subcellular ICC-IF). |
Experiment evidence
IHC & IF images showing CPLX1 staining
A05254 · IHCIHC analysis of CPLX1 using anti-CPLX1 antibody (A05254). CPLX1 was detected in a paraffin-embedded section of rat brain tissue. Heat mediat
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000168993-CPLX1/tissue/cerebral+cortex#imid_20693944
HPA · Adrenal glandHuman Protein Atlas IHC, Adrenal gland. Source: https://www.proteinatlas.org/ENSG00000168993-CPLX1/tissue/adrenal+gland#imid_1266
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000168993-CPLX1/tissue/colon#imid_20693862
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000168993-CPLX1/tissue/liver#imid_20693871
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA071191; green = CPLX1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA071191; green = CPLX1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CPLX1 IHC & IF
🧪Run cerebellum first: cells in the granular layer should stain (HPA: High in cerebellar cells in granular layer). Run adipose tissue as the negative tissue; adipocytes should remain unstained (HPA: Not detected in adipocytes). On the cerebellar slide, use morphologically identified non-neuronal cells as an internal background reference, while interpreting signal in the context of CPLX1’s neuronal and presynaptic localization (UniProt O14810).
Positive control tissue: Adrenal gland (Medullary cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CPLX1 in A-549, Hep-G2, U2OS, with annotated localisation: Vesicles (uncertain) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control, a concentration-matched rabbit IgG isotype control for the rabbit catalog antibody, and CPLX1 knockout tissue or a validated peptide-block control (catalog caption: rabbit antibody A05254; standard IHC practice). Quench endogenous peroxidase before chromogenic detection and assess tissue background on the no-primary slide; for IF, check brain autofluorescence in an unstained section (standard IHC/IF practice).
⚠️Feasibility: The selected paraffin-section rat brain caption reports heat retrieval in EDTA at pH 8.0 and antibody incubation at 1:200 overnight at 4°C, but its fixative is unreported (catalog caption: A05254). No target-specific fixation window or fixation effect is reported in the supplied evidence, and the caption does not establish fixation (catalog caption: A05254). Paraffin IHC is demonstrated by that caption; the supplied evidence does not establish whether frozen sections or IF are easier, and brain autofluorescence should be assessed if IF is used (catalog caption: A05254; standard IF practice). The selected A05254 tissue-IHC caption documents paraffin sections, but does not specify the fixative (selected-SKU IHC image A05254).
HPA tissue IHC evidence for CPLX1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — Medium consistency between antibody staining and RNA expression data. Caution, targets protein from more than one gene.). Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Medullary cells | High | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | High | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | High | Protein (IHC) | HPA → |
| Caudate | Neuronal cells | Medium | Protein (IHC) | HPA → |
| Hippocampus | Neuronal cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Appendix | Endocrine cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced CPLX1 IHC Tips
Troubleshoot CPLX1 staining in paraffin sections by checking retrieval, compartment, tissue pattern, and controls before comparing chromogenic signal across samples.
Which retrieval conditions should I try first for weak CPLX1 staining?
Start with heat-mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet A05254). The selected image used this condition before overnight incubation with the catalog antibody at 1:200 and 4°C (datasheet A05254). If staining is weak, compare retrieval duration on adjacent sections while keeping antibody concentration, detection, and imaging conditions constant; use the same run to check tissue preservation. Include a neuronal region expected to stain as a positive control, since CPLX1 is enriched in nervous tissue (UniProt O14810 tissue specificity; HPA: neuronal staining in cerebral cortex). Excessive heat can damage morphology, so judge signal alongside intact cellular detail (standard IHC practice).
How should I troubleshoot fixation-related loss of CPLX1 signal?
The selected paraffin-section caption does not state a fixative, so target-specific CPLX1 sensitivity to fixation is unknown (datasheet A05254). Record the fixative, fixation time, tissue thickness, and processing history for each specimen, then compare sections processed under matched conditions (standard IHC practice). When signal varies between specimens, first confirm that retrieval, the 1:200 primary incubation, and chromogenic development were consistent with the tested workflow (datasheet A05254). Compare staining with morphology and an appropriate positive control in the same run; poorly preserved tissue can make cellular localisation difficult to judge (standard IHC practice). Do not infer fixation tolerance from the reported tissue distribution (HPA: tissue IHC profile).
Where should convincing CPLX1 staining appear in brain sections?
Look for cytoplasmic and synaptic staining, with particular attention to neuronal processes and presynaptic regions (UniProt O14810 subcellular location; HPA: synaptic positivity in brain). CPLX1 is also reported in the neuronal perikaryon and is enriched at synaptic-releasing sites in mature neurons (UniProt O14810 subcellular location). Examine the pattern at low and high magnification so dense neuropil staining is not mistaken for staining in every cell body (standard IHC practice). Cerebral cortical neuronal cells and cerebellar granular-layer cells are reported as high-staining reference populations (HPA: cerebral cortex and cerebellum). Predominantly nuclear signal warrants a control review because it does not match the recorded cytoplasmic and presynaptic localisation (UniProt O14810 subcellular location).
How can I assess whether an unexpected staining pattern reflects the CPLX1 epitope?
The supplied record lists a single 1–134 Complexin-1 chain, with no annotated isoforms, glycosylation sites, or modified residues (UniProt O14810 processing, isoforms, and modifications). It also reports no transmembrane segment, consistent with assessing an intracellular epitope in stained cells (UniProt O14810 topology and subcellular location). The antibody epitope is not supplied, so these annotations cannot establish which tissue-processing conditions preserve its binding (datasheet A05254; UniProt O14810 record). Compare staining with an independently validated antibody targeting a distinct epitope, if available, and inspect matched negative controls (standard IHC practice). Interpret agreement by cell type and compartment, since the HPA profile cautions that its antibodies can target proteins from more than one gene (HPA: tissue IHC reliability description).
How should I check CPLX1 localisation by multiplex immunofluorescence?
For a separate IF experiment, pair CPLX1 with a marker for the expected neuronal population, such as an inhibitory-neuron marker in hippocampus or cerebellum (UniProt O14810 tissue specificity). Choose spectrally separated fluorophores and place the weaker signal in a far-red channel when tissue autofluorescence is troublesome (standard IF practice). Because CPLX1 is cytosolic and has no transmembrane segment, use controlled permeabilisation to reach the intracellular antigen while preserving fine processes (UniProt O14810 topology and subcellular location; standard IF practice). Run single-stain and secondary-only controls to assess bleed-through and background, and inspect puncta against the cell marker (standard IF practice). Optimise IF fixation independently; the paraffin-section caption reports no fixative (datasheet A05254).
What should I change when CPLX1 DAB staining looks diffuse or nonspecific?
First compare a no-primary control with the test section to identify signal from secondary reagents or endogenous peroxidase (standard chromogenic IHC practice). The selected workflow used a 10% goat-serum block, a 1:200 rabbit primary overnight at 4°C, and DAB detection (datasheet A05254). If background persists, review wash stringency, primary concentration, peroxidase blocking, and DAB development on matched sections (standard IHC practice). Preserve the expected neuronal cytoplasmic and synaptic pattern while optimising, rather than judging success by darker overall colour (UniProt O14810 subcellular location; HPA: tissue IHC profile). Treat widespread staining in otherwise low-staining reference tissue cautiously; kidney tubule cells are reported as low (HPA: kidney).
How should I quantify CPLX1 IHC across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Define neuronal regions and cell populations before scoring, then apply the same segmentation and DAB threshold to every section (standard quantitative IHC practice). For cell bodies, report the percentage of positive cells and an intensity-weighted H-score; for synaptic-rich areas, report positive area or optical-density signal per mm² (standard quantitative IHC practice). Normalise cell counts to the number of eligible neurons and area-based measurements to analysable tissue area, excluding folds and damaged edges (standard quantitative IHC practice). Keep section thickness, retrieval, antibody incubation, and development matched, using the documented 1:200 condition as the starting point (datasheet A05254). Separate cell-body from neuropil measurements because CPLX1 has both perikaryal and presynaptic localisation (UniProt O14810 subcellular location).
How can I distinguish true CPLX1 positivity from staining artefacts?
A plausible positive shows neuronal cytoplasmic or synaptic staining in brain, consistent with the reported subcellular pattern and tissue enrichment (UniProt O14810 subcellular location and tissue specificity; HPA: tissue IHC profile). Check whether staining follows cell anatomy and appears in expected reference populations, including cerebral cortical neurons (HPA: cerebral cortex). Isolated nuclear staining, section-edge accentuation, necrotic areas, and signal reproduced in a no-primary control warrant investigation before scoring (UniProt O14810 subcellular location; standard IHC practice). Endogenous peroxidase and uneven DAB development can create chromogenic signal unrelated to antibody binding (standard chromogenic IHC practice). Corroborate unusual patterns independently because the HPA assessment is Supported with medium RNA–staining consistency and cautions about antibodies targeting multiple genes (HPA: tissue IHC reliability description).
Boster reagents
Best CPLX1 / Complexin-1 IHC Antibodies
A05254 has real IHC data from paraffin-embedded rat brain (A05254 image caption). IF/ICC applications and human, mouse, and rat reactivity are catalog listed (catalog A05254).
Real IHC data
Anti-CPLX1 Antibody
Cat # A05254
A05254 has an IHC image from a paraffin-embedded rat brain section (A05254 image caption). The catalog lists A05254 for IHC, IF, and ICC with human, mouse, and rat reactivity; it provides no IF image (catalog A05254).
Which to pick: For tissue IHC, choose A05254: its image shows staining in a paraffin-embedded rat brain section after heat retrieval in EDTA at pH 8.0 (A05254 image caption). For IF/ICC, A05254 is the catalog-listed option, though no IF image is supplied (catalog A05254). For cross-species work, A05254 is a rabbit polyclonal listed as reactive with human, mouse, and rat; its IHC caption does not report the fixative (catalog A05254; A05254 image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O14810 (CPLX1_HUMAN, Complexin-1).
- Human Protein Atlas. CPLX1 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. CPLX1 subcellular location (ICC-IF): Mainly localized to vesicles. Caution: Based on antibodies targeting proteins from multiple genes..
- Human Protein Atlas. CPLX1 antibody validation summary (2 antibodies).
- The Proteome of the Dentate Terminal Zone of the Perforant Path Indicates Presynaptic Impairment in Alzheimer Disease. Molecular & cellular proteomics : MCP 2020 — PMC6944231.
- CPLX1 is a novel prognostic biomarker in CRC correlating with immunotherapy resistance and ferroptosis. Frontiers in immunology 2025 — PMC12283636.
- The schizophrenia risk gene product miR-137 alters presynaptic plasticity. Nature neuroscience 2015 — PMC4506960.
- PubMed PMID:7553862 — UniProt-cited evidence.
- PubMed PMID:24722188 — UniProt-cited evidence.
- PubMed PMID:21697133 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CPLX1 (Complexin-1). Expected localisation Cytoplasmic; synaptic in brain (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A05254). Validated IHC antibody: A05254 at 1:50 (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Medullary cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded rat brain tissue; fixative not specified (datasheet A05254); 2. Fixation: Image fixative and duration unreported (datasheet A05254); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: EDTA pH 8.0 (datasheet A05254); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A05254); 8. Primary antibody: Rabbit anti-CPLX1, 1:50 (datasheet A05254); 9. Primary incubation: Overnight at 4 °C (datasheet A05254). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Staining may reflect proteins from more than one gene (HPA tissue IHC); Isoform / epitope: No annotated isoforms or processing; one 1–134 chain (UniProt); Regulation: Overexpressed in Parkinson disease substantia nigra (UniProt). Evidence: UniProt O14810, HPA tissue IHC · Supported, HPA ICC-IF · Mainly localized to vesicles. Caution: Based on antibodies targeting…, Datasheet A05254, PMC6944231, PMC12283636. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CPLX1/immunohistochemistry-ihc-guide.