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BCS1L / Mitochondrial chaperone BCS1 · IHC design guide
Design Immunohistochemistry for BCS1L
Plan BCS1L IHC in paraffin sections with guidance on fixation, antibody dilution and staining interpretation. Cytoplasmic tissue staining is reported (HPA tissue IHC); hepatocytes provide a high-staining reference, while adipocytes are reported as unstained (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
BCS1L 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); inner mitochondrial membrane at the molecular level (UniProt) | |
| Staining pattern | Widespread cytoplasmic staining across tissue cells (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | Adipose tissue |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across paraffin specimens. (selected-SKU IHC image A04885) | |
| Caveat | Adipocytes may be unstained despite the ubiquitous profile (HPA tissue IHC) | |
| Regulation | No specific expression regulator reported (UniProt) | |
| Isoform / epitope | No isoforms annotated; chain 2–419, with residues 33–419 facing the matrix (UniProt) |
Section 1
Recommended BCS1L IHC & IF Protocols
The catalog antibody’s IHC-P protocol is paired with one published BCS1L paraffin-section method (PMC13039997).
| Sample | Paraffin-embedded human stomach tissue; fixative not specified (datasheet A04885) |
| Fixation | Image fixative and duration unreported (datasheet A04885); 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-BCS1L, 1:50-1:200 (datasheet A04885) |
| 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 | BCS1L-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Ubiquitous cytoplasmic expression. 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 published method uses microwave EDTA retrieval (PMC13039997).
Section 2
What Is the Expected BCS1L Staining Pattern?
BCS1L is an inner mitochondrial membrane protein with residues 16–32 spanning the membrane and residues 33–419 facing the matrix (UniProt Q9Y276 topology). In paraffin tissue sections, expect cytoplasmic staining across many cell types, including strong staining in several glandular epithelia and hepatocytes (HPA: ubiquitous cytoplasmic expression; High in glandular cells and hepatocytes). HPA rates the tissue IHC pattern Supported, with medium consistency between staining and RNA data (HPA: reliability Supported).
| Distinct cytoplasmic staining in colon or duodenal glandular cells, or in hepatocytes. | This fits HPA's High tissue IHC observations (HPA: High in colon and duodenal glandular cells; High in hepatocytes). A fine granular pattern is plausible for a mitochondrial protein, but tissue IHC alone does not prove mitochondrial colocalisation (UniProt Q9Y276: inner mitochondrial membrane). |
| Predominantly nuclear, cell-surface, or extracellular staining with little cytoplasmic signal. | That distribution conflicts with the reported cytoplasmic tissue pattern and inner membrane assignment (HPA: ubiquitous cytoplasmic expression; UniProt Q9Y276 topology). Check the no-primary control and compare a known-positive tissue before interpreting it as BCS1L. |
| Strong staining confined to adipocytes while nearby expected-positive cells remain unstained. | HPA reports adipocytes as Not detected in its adipose tissue sample (HPA: Not detected in adipocytes). Consider nonspecific binding or endogenous chromogen activity; this observation alone does not establish antibody cross-reactivity (standard IHC practice). |
| Uniform color over cells, stroma, and section edges, obscuring cell boundaries. | This is more consistent with background than a readable cellular pattern (standard IHC practice). A no-primary control can reveal detection-system or endogenous activity; compare it with the stained section before scoring BCS1L. |
| No visible staining in a properly preserved colon or liver section. | This disagrees with the sampled HPA High observations in glandular cells or hepatocytes (HPA: High in colon glandular cells and hepatocytes). Check tissue quality, antibody handling, detection, and a same-run positive control before calling the specimen negative (standard IHC practice). |
💡Expected BCS1L appearanceCall a section positive when identifiable glandular cells or hepatocytes show clear cytoplasmic staining, potentially fine and granular, above the no-primary background (HPA: High in glandular cells and hepatocytes; UniProt Q9Y276: inner mitochondrial membrane); isolated nuclear or diffuse extracellular color is suspect (standard IHC practice).
| Compartment and topology | BCS1L has one transmembrane segment at residues 16–32 and a matrix-facing region at 33–419 (UniProt Q9Y276 topology). Interpret an IHC cytoplasmic pattern in that context; light microscopy cannot resolve the inner membrane by itself (standard IHC practice). |
| Tissue and cell selection | HPA reports High staining in multiple glandular epithelia, esophageal squamous epithelial cells, and hepatocytes; adipocytes are Not detected and marrow hematopoietic cells are low in the sampled tissues (HPA: tissue IHC). Use those observations to choose comparison fields without treating one negative cell type as a universal absence. |
| Strength of tissue evidence | The tissue profile is Supported, with medium consistency between antibody staining and RNA expression (HPA: reliability Supported). Both listed antibodies have Supported IHC status (HPA: HPA037700 and HPA037701); this supports a reference pattern but does not validate every stained structure. |
| IF/ICC Q&A: should vesicular fluorescence define the IHC result? | No. HPA's ICC-IF main vesicle location is Uncertain, while its additional sperm mid-piece location is Approved (HPA: subcellular ICC-IF). Interpret paraffin IHC against the tissue cytoplasmic pattern and UniProt inner membrane assignment; IF/ICC needs its own validation (HPA: tissue IHC; UniProt Q9Y276 topology). |
| Processing and fixation evidence | UniProt lists no signal peptide or propeptide and annotates a chain spanning residues 2–419 (UniProt Q9Y276 processing). The supplied sources report no BCS1L-specific fixation sensitivity or retrieval condition; assess any retrieval change using matched controls (standard IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| Known-positive glandular cells and hepatocytes are blank. | A failed staining run, weak detection, or unsuitable tissue quality is possible (standard IHC practice); HPA reports High staining in these cells (HPA: tissue IHC). | Inspect a same-run positive control and section quality, then review the antibody dilution and retrieval settings used for the run (standard IHC practice). Do not infer a BCS1L-specific retrieval requirement from HPA. |
| The whole section develops diffuse brown color. | Nonspecific binding or detection background can obscure the reported cytoplasmic pattern (standard IHC practice; HPA: ubiquitous cytoplasmic expression). | Compare a no-primary control; review blocking, washes, detection reagent, and chromogen development (standard IHC practice). Score cellular staining only after background is controlled. |
| No-primary sections still show color in the same cells. | Endogenous enzyme activity or detection-system background may contribute to chromogenic signal (standard IHC practice). | Review the appropriate endogenous-activity block and detection controls for the chemistry in use (standard IHC practice). Avoid assigning control-positive color to BCS1L. |
| Adipocytes appear strongly positive while expected-positive epithelium is weak. | The pattern conflicts with HPA's sampled Not detected adipocytes and High glandular cells (HPA: tissue IHC); nonspecific signal is possible (standard IHC practice). | Compare cell morphology and no-primary staining, then repeat alongside a documented High epithelial tissue (HPA: tissue IHC; standard IHC practice). |
| Only nuclei stain, despite a clean background. | Nuclear-only signal disagrees with the HPA cytoplasmic tissue profile and UniProt inner membrane location (HPA: tissue IHC; UniProt Q9Y276 topology). | Check antibody identity and detection controls, and compare with a same-run High tissue (HPA: tissue IHC; standard IHC practice). Do not score nuclear-only staining as the expected pattern. |
| Signal differs between adjacent cell types in one section. | Variation can be biological: HPA reports High staining in some cells, low staining in marrow hematopoietic cells, and Not detected adipocytes (HPA: tissue IHC). Technical background remains possible (standard IHC practice). | Score named cell types separately, compare comparable tissue regions, and inspect controls before calling a whole section positive or negative (standard IHC practice). |
Experiment evidence
IHC & IF images showing BCS1L staining
A04885 · IHCImmunohistochemistry of paraffin-embedded human stomach using BCS1L antibody at dilution of 1:100 .Perform microwave antigen retrieval with
A04885 · IHCImmunohistochemistry of paraffin-embedded rat brain using BCS1L antibody at dilution of 1:100 .Perform microwave antigen retrieval with 10 m
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000074582-BCS1L/tissue/cerebral+cortex#imid_10730391
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000074582-BCS1L/tissue/colon#imid_10730325
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000074582-BCS1L/tissue/liver#imid_10730318
HPA · PancreasHuman Protein Atlas IHC, Pancreas. Source: https://www.proteinatlas.org/ENSG00000074582-BCS1L/tissue/pancreas#imid_10730277
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA037701; green = BCS1L, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA037701; green = BCS1L, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for BCS1L IHC & IF
🧪Run colon first: glandular cells should stain (HPA: High in colon glandular cells). Use adipose tissue as the biological low-signal comparator (HPA: Not detected in adipocytes); within the colon slide, cells without distinct chromogenic signal should show only background, but should not be called proven BCS1L-negative cells because expression is ubiquitous (UniProt Q9Y276: tissue specificity).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show BCS1L in A-431, U-251MG, U2OS, Sperm, with annotated localisation: Vesicles (uncertain) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control, a host-species- and clonality-matched isotype control, and BCS1L-knockout material as a target-specific control where available. Block endogenous peroxidase and check for residual chromogenic background in the colon section (HPA: High in colon glandular cells).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported in the supplied evidence; the selected A04885 paraffin-section caption does not report a fixative (datasheet: fixative unreported). The caption uses microwave retrieval in 10 mM PBS at pH 7.2 and a 1:100 antibody dilution, so retrieval should be included when assessing this IHC setup (datasheet: A04885 tissue-IHC caption). Frozen sections and IF are not established as easier by the supplied evidence; IF interpretation needs care because the HPA ICC-IF location is mainly vesicular with uncertain confidence, while UniProt places BCS1L in the mitochondrial inner membrane (HPA: vesicles uncertain; UniProt Q9Y276: subcellular location).
HPA tissue IHC evidence for BCS1L
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — 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 | Glandular cells | High | Protein (IHC) | HPA → |
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
| Esophagus | Squamous epithelial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced BCS1L IHC Tips
Troubleshoot BCS1L staining in paraffin sections by checking retrieval, compartmental pattern, controls, and scoring before interpreting intensity.
Which retrieval conditions should I try when BCS1L staining is weak?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval rule: cytoplasmic or membrane antigen). If staining remains weak, compare a section retrieved by microwave in 10 mM PBS at pH 7.2, the condition reported for catalog antibody A04885 in paraffin-embedded human stomach at 1:100 (A04885 tissue-IHC caption). Keep section thickness, antibody dilution, detection, and imaging conditions matched across the comparison (standard IHC practice). Include a no-primary control, and judge improved signal by its intracellular pattern as well as intensity, since BCS1L is assigned to the mitochondrial inner membrane (UniProt Q9Y276 localisation).
Could fixation explain inconsistent BCS1L staining between sections?
Target-specific sensitivity of BCS1L to fixation is unknown from the supplied evidence; the A04885 paraffin-section caption does not state a fixative (A04885 tissue-IHC caption). Record the fixative, fixation duration, processing schedule, and section age for each specimen before comparing staining (standard IHC practice). If these variables differ, stain matched sections together using one retrieval and detection run, with a no-primary control to expose procedural background (standard IHC practice). Evaluate any change in signal within comparable cells and tissue regions, rather than attributing it to BCS1L-specific fixation sensitivity without direct evidence (standard IHC interpretation).
What cellular staining pattern is plausible for BCS1L in paraffin sections?
Expect intracellular cytoplasmic signal at light-microscope resolution, consistent with the mitochondrial inner-membrane assignment and ubiquitous tissue expression (UniProt Q9Y276 localisation and tissue specificity; HPA tissue IHC profile). BCS1L has a transmembrane segment at residues 16–32, with residues 33–419 assigned to the mitochondrial matrix side (UniProt Q9Y276 topology). Do not require a sharply resolved mitochondrial network in chromogenic sections; compare staining across intact cells and a no-primary control (standard IHC practice). Interpret diffuse extracellular staining or a dominant nuclear pattern cautiously because neither follows the recorded inner-membrane location (UniProt Q9Y276 localisation; standard IHC interpretation).
How should I assess an unexpected BCS1L epitope-dependent result?
Check the antibody's stated immunogen or epitope against the 419-residue BCS1L sequence before changing retrieval conditions (UniProt Q9Y276 length; standard IHC practice). The record lists one transmembrane segment at residues 16–32, an intermembrane-space segment at 2–15, and a matrix-facing region at 33–419 (UniProt Q9Y276 topology). No isoforms are annotated, and phosphotyrosine at residue 181 is listed as an example modified residue (UniProt Q9Y276 isoforms and modified residues). Without an identified antibody epitope, do not assign weak staining to isoform choice, membrane orientation, or that modification; instead compare retrieval conditions on matched sections with controls (standard IHC interpretation).
How can IF help investigate an ambiguous chromogenic BCS1L pattern?
Use IF as a separate localisation check, while interpreting the paraffin-section result through its own IHC controls (standard IHC/IF practice). Multiplex BCS1L with a marker for the expected cell population, such as glandular cells in colon, where HPA reports high staining, and add a mitochondrial marker to assess compartmental agreement (HPA tissue IHC: colon glandular cells High; UniProt Q9Y276 localisation). Choose fluorophores and unstained controls after checking tissue autofluorescence in each channel (standard IF practice). Because residues 33–419 face the matrix, permeabilisation may need optimisation if the antibody epitope lies there; its epitope is not specified here (UniProt Q9Y276 topology; standard IF practice).
How do I distinguish weak BCS1L signal from chromogenic background?
Run no-primary and detection-only controls alongside stained sections to identify signal from the detection system (standard IHC practice). For peroxidase-based detection, include an endogenous peroxidase block and assess whether residual colour follows tissue structures or cut edges rather than intact cells (standard IHC practice). Titrate the catalog antibody around the caption's 1:100 condition only when using that same antibody, and keep retrieval and development time fixed during the comparison (A04885 tissue-IHC caption; standard IHC practice). Treat widespread extracellular deposit or equally strong no-primary staining as background, especially when it obscures the cytoplasmic pattern reported in tissue IHC (HPA tissue IHC profile; standard IHC interpretation).
How should I quantify BCS1L staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the scored cell population and tissue region before reviewing intensity, then apply the same rule to every section (standard IHC practice). For chromogenic staining, report the percentage of positive cells and an H-score using intensity categories 0–3, or report positive-cell density per mm² when cell counts matter (standard IHC scoring practice). Normalise counts to the number of evaluable cells or sampled tissue area, and compare matched cell populations rather than whole sections with different composition (standard IHC practice). Record retrieval, antibody dilution, staining batch, and background threshold because these affect comparisons; HPA describes tissue staining as ubiquitous cytoplasmic expression (HPA tissue IHC profile; standard IHC practice).
When is a BCS1L-positive IHC result biologically credible?
Look for staining within intact cells in a plausible cytoplasmic compartment, consistent with BCS1L's mitochondrial inner-membrane location (UniProt Q9Y276 localisation; HPA tissue IHC profile). Compare the pattern with a no-primary control and with annotated tissue examples: HPA reports high signal in liver hepatocytes and no detection in adipocytes (HPA tissue IHC: liver hepatocytes High; adipose adipocytes Not detected). Discount strong staining limited to section edges, necrotic regions, or sites retaining endogenous enzyme activity until controls exclude artefact (standard IHC interpretation). Because HPA rates tissue-IHC reliability as Supported with medium staining–RNA consistency, treat an unexpected cell or compartment pattern as a result requiring independent confirmation (HPA tissue IHC reliability; standard IHC interpretation).
Boster reagents
Best BCS1L / Mitochondrial chaperone BCS1 IHC Antibodies
A04885 has IHC images from paraffin-embedded human stomach and rat brain (catalog IHC captions). IF/ICC is listed for human, mouse and rat reactivity, but no IF image is provided (catalog applications, reactivity, IF image alts).
Real IHC data
Anti-Mitochondrial chaperone BCS1 BCS1L Antibody
Cat # A04885
A04885 is shown staining paraffin-embedded human stomach and rat brain at 1:100 after microwave antigen retrieval (catalog IHC captions). Its listed applications include IHC and IF/ICC, with human, mouse and rat reactivity; no IF image is provided (catalog applications, reactivity, IF image alts).
Which to pick: For tissue IHC, choose A04885: its own images document paraffin-embedded human stomach and rat brain, while the fixative is unreported (catalog IHC captions). For IF/ICC or work across human, mouse and rat samples, A04885 is the listed option based on its applications and reactivity; no IF image is provided (catalog applications, reactivity, IF image alts). It is rabbit-hosted, with no clone specified (catalog host, clone).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9Y276 (BCS1_HUMAN, Mitochondrial chaperone BCS1).
- Human Protein Atlas. BCS1L tissue IHC expression (reliability: Supported).
- Human Protein Atlas. BCS1L subcellular location (ICC-IF): Mainly localized to vesicles. In addition localized to the mid piece..
- Human Protein Atlas. BCS1L antibody validation summary (2 antibodies).
- Quantitative proteomics analysis of altered protein expression in the placental villous tissue of early pregnancy loss using isobaric tandem mass tags. BioMed research international 2014 — PMC3971554.
- Splice-switching of the oncogenic BCS1L isoform suppresses ovarian cancer progression by disrupting mitochondrial function. Cell death & disease 2026 — PMC13039997.
- Respiratory chain complex III deficiency due to mutated BCS1L: a novel phenotype with encephalomyopathy, partially phenocopied in a Bcs1l mutant mouse model. Orphanet journal of rare diseases 2017 — PMC5399415.
- PubMed PMID:9878253 — UniProt-cited evidence.
- PubMed PMID:11528392 — UniProt-cited evidence.
- PubMed PMID:12215968 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for BCS1L (Mitochondrial chaperone BCS1). Expected localisation Cytoplasmic tissue staining (HPA tissue IHC); inner mitochondrial membrane at the molecular level (UniProt). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A04885 at 1:50-1:200 (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human stomach tissue; fixative not specified (datasheet A04885); 2. Fixation: Image fixative and duration unreported (datasheet A04885); 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-BCS1L, 1:50-1:200 (datasheet A04885); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across paraffin specimens. (selected-SKU IHC image A04885); Caveat: Adipocytes may be unstained despite the ubiquitous profile (HPA tissue IHC); Isoform / epitope: No isoforms annotated; chain 2–419, with residues 33–419 facing the matrix (UniProt); Regulation: No specific expression regulator reported (UniProt). Evidence: UniProt Q9Y276, HPA tissue IHC · Supported, HPA ICC-IF · Mainly localized to vesicles. In addition localized to the mid piece., Datasheet A04885, PMC13039997. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/BCS1L/immunohistochemistry-ihc-guide.