This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
IARS1 / Isoleucine--tRNA ligase, cytoplasmic · IHC design guide
Design Immunohistochemistry for IARS1
Plan human paraffin IHC for IARS1 using the catalog antibody at 2–5 μg/ml (datasheet A06805-1). Assess cytoplasmic staining in Purkinje cells or lung macrophages (HPA tissue IHC), and interpret intensity with the reported low consistency between antibody staining and RNA expression in mind (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
IARS1 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 staining in several tissues (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic signal in Purkinje cells and lung macrophages (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A06805-1) | |
| Positive control | Cerebellum+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 paraffin sections (standard IHC practice; not target-specific) | |
| Caveat | Staining has low consistency with RNA expression (HPA tissue IHC) | |
| Regulation | Low tissue specificity at RNA level (HPA tissue RNA) | |
| Isoform / epitope | No annotated isoforms or propeptide; one chain (UniProt) |
Section 1
Recommended IARS1 IHC & IF Protocols
The catalog antibody uses EDTA pH 8.0 heat-mediated retrieval (datasheet A06805-1). The published IARS1 protocol below reports cell and tissue preparation and antibody incubation (PMC13584253 methods).
| Sample | Paraffin-embedded human esophageal squamous carcinoma tissue; fixative not specified (datasheet A06805-1) |
| Fixation | Image fixative and duration unreported (datasheet A06805-1); 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 A06805-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A06805-1) |
| Primary antibody | Rabbit anti-IARS1, 2-5 μg/ml (datasheet A06805-1) |
| Primary incubation | Overnight at 4 °C (datasheet A06805-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A06805-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | IARS1-positive staining in purkinje cells of cerebellum (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in several tissues. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 heat-mediated retrieval (datasheet A06805-1); the article mentions antigen retrieval but gives no buffer or pH (PMC13584253 methods).
Section 2
What Is the Expected IARS1 Staining Pattern?
IARS1 is a cytoplasmic, cytosolic protein with no transmembrane segment (UniProt P41252). In paraffin section IHC, expect cytoplasmic staining in selected cells, including Purkinje cells, cortical and hippocampal neurons, lung macrophages, and glandular cells in the cervix, gallbladder, and salivary gland (HPA: High). Treat the pattern as a guide rather than a definitive specificity test: HPA rates tissue staining Approved but reports low consistency with RNA expression (HPA: tissue IHC reliability).
| Clear cytoplasmic signal in Purkinje cells or lung macrophages, with cell boundaries still readable. | This fits the expected compartment (UniProt P41252: cytosol) and reported high staining in those cells (HPA: High). Compare intensity with nearby cells on the same section; staining alone does not establish antibody specificity (HPA: Approved, low RNA consistency). |
| Signal is predominantly nuclear, with little cytoplasmic staining. | Investigate a compartment mismatch against UniProt's cytosolic assignment (UniProt P41252). HPA reports nucleoplasm in ICC-IF as uncertain, so nuclear signal alone cannot prove an artefact (HPA: subcellular); check the IHC controls before interpreting it. |
| Strong signal appears in a cell population HPA lists as not detected, such as adipocytes. | Consider cross-reactivity or endogenous detection activity and compare a no-primary control (HPA: adipocytes Not detected; general IHC practice). HPA's result is an observed staining level, not proof that every adipocyte lacks IARS1 (HPA: tissue IHC). |
| Diffuse chromogen covers cells and surrounding tissue without a clear cytoplasmic pattern. | Treat this as background until controls separate specific signal from nonspecific binding or endogenous detection activity (general IHC practice). Uniform haze cannot be scored as IARS1 localisation; the supported reference pattern is cytoplasmic (UniProt P41252; HPA: tissue IHC). |
| A proposed positive control, such as cerebellar Purkinje cells, has no detectable signal. | The run is inconclusive: Purkinje cells stain High in HPA IHC, but HPA's Approved rating carries low RNA consistency (HPA: tissue IHC). Check section quality and detection controls, then review retrieval and antibody conditions (general IHC practice). |
💡Expected IARS1 appearanceCall a result consistent when distinct cytoplasmic staining is strongest in an HPA High cell population, such as Purkinje cells or lung macrophages (UniProt P41252; HPA: High); isolated strong nuclear signal or uniform background warrants control checks (HPA: nucleoplasm uncertain; general IHC practice).
| Cell and tissue choice | Use an HPA High population to judge a positive result, such as cortical neurons or salivary glandular cells (HPA: High). Liver hepatocytes are Low in HPA IHC despite UniProt reporting liver protein expression; those statements describe different evidence and need not yield the same slide intensity (HPA: Low; UniProt P41252: tissue specificity). |
| Strength of staining evidence | HPA calls tissue IHC Approved while flagging low consistency with RNA expression; its listed antibody HPA029806 is IHC Approved, with no Enhanced designation supplied (HPA: tissue IHC reliability; HPA: antibody validation). Interpret unexpected staining with controls rather than treating the reference pattern as an absolute map. |
| Topology and processing | UniProt assigns IARS1 to cytoplasm and cytosol, with no transmembrane segment, signal peptide, or propeptide (UniProt P41252). These annotations support a cellular cytoplasmic readout; they do not identify an antibody epitope or predict how retrieval will perform (UniProt P41252 topology; general IHC practice). |
| Q: Does ICC-IF justify a nuclear IHC call? | A: HPA supports cytosol in ICC-IF but labels nucleoplasm uncertain; images are listed for A-431 and U-251MG (HPA: subcellular ICC-IF). Use that observation as context when reviewing nuclear IHC signal, not as a paraffin IHC localisation standard (HPA: tissue IHC profile). |
| Situation | Likely cause | Next action |
|---|---|---|
| No cytoplasmic signal in an HPA High control population. | The IHC run may lack usable antigen exposure or detection; HPA's High result is a reference observation, not a guaranteed result for every run (HPA: tissue IHC; general IHC practice). | Inspect section integrity and detection controls, then optimize antigen retrieval and antibody conditions for the chosen paraffin IHC assay (general IHC practice). |
| Predominantly nuclear staining. | Possible nonspecific signal or a compartment discrepancy; ICC-IF nucleoplasm is uncertain while cytosol is supported (HPA: subcellular; UniProt P41252). | Compare no-primary and positive controls, and check whether cytoplasmic signal remains visible before assigning localisation (general IHC practice). |
| Strong staining in adipocytes or heart cardiomyocytes. | Both are Not detected in HPA tissue IHC; cross-reactivity or endogenous detection activity is possible, but HPA does not establish absolute protein absence (HPA: tissue IHC). | Compare matched no-primary controls and inspect the cell-specific pattern before scoring the unexpected population (general IHC practice). |
| Diffuse staining throughout the section. | Nonspecific binding or endogenous detection activity can obscure the expected cytoplasmic distribution (general IHC practice; UniProt P41252: cytosol). | Check no-primary controls, blocking, washing, and detection conditions; score only distinguishable cellular signal (general IHC practice). |
| Low signal in liver hepatocytes is read as assay failure. | HPA reports hepatocytes as Low in tissue IHC, although UniProt reports liver protein expression (HPA: Low; UniProt P41252: tissue specificity). | Judge run performance against an HPA High cell population and its controls before interpreting weak liver staining (HPA: High; general IHC practice). |
| A not-detected comparison tissue shows faint staining. | HPA's Not detected category describes its observed IHC result; faint signal may reflect background or assay conditions (HPA: tissue IHC; general IHC practice). | Compare the same cell type with a no-primary control and assess whether signal is cytoplasmic and reproducible before calling it positive (UniProt P41252; general IHC practice). |
Experiment evidence
IHC & IF images showing IARS1 staining
A06805-1 · IHCIHC analysis of IARS1 using anti-IARS1 antibody (A06805-1). IARS1 was detected in a paraffin-embedded section of human esophageal squamous c
A06805-1 · IHCIHC analysis of IARS1 using anti-IARS1 antibody (A06805-1). IARS1 was detected in a paraffin-embedded section of human liver cancer tissue.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000196305-IARS1/tissue/cerebral+cortex#imid_7580208
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000196305-IARS1/tissue/colon#imid_7580150
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000196305-IARS1/tissue/liver#imid_7580135
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000196305-IARS1/tissue/kidney#imid_7580152
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA029806; green = IARS1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA029806; green = IARS1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for IARS1 IHC & IF
🧪Run cerebellum first and score Purkinje cells for IARS1 staining (HPA: High in Purkinje cells). Run adipose tissue as a comparison, focusing on adipocytes (HPA: Not detected in adipocytes); neighboring cells without specific staining on the cerebellum slide should show only background, without assuming a particular cell type is negative (standard IHC practice).
Positive control tissue: Cerebellum (Purkinje cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show IARS1 in A-431, U-251MG, with annotated localisation: Nucleoplasm (uncertain), Cytosol (supported) (HPA subcellular).
Technical controls: Include no-primary (secondary-only), species- and clonality-matched rabbit IgG isotype, and IARS1 knockout or validated peptide-block controls (standard IHC practice; selected-SKU caption: rabbit primary). Quench endogenous peroxidase and distinguish tissue pigment from DAB signal in cerebellum (standard chromogenic IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A06805-1 tissue-IHC caption does not state the fixative (selected-SKU caption: fixative unreported). The caption uses heat-mediated EDTA retrieval at pH 8.0, but does not establish whether retrieval is required; no supplied comparison establishes that frozen sections or IF are easier (selected-SKU caption: EDTA retrieval; supplied evidence: no matched comparison). For cerebellar IF, check neuronal lipofuscin autofluorescence before interpreting signal (standard IF practice).
HPA tissue IHC evidence for IARS1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low 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 |
|---|---|---|---|---|
| Cerebellum | Purkinje cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | High | Protein (IHC) | HPA → |
| Cervix | Glandular cells | High | Protein (IHC) | HPA → |
| Gallbladder | Glandular cells | High | Protein (IHC) | HPA → |
| Hippocampus | Neuronal cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Epididymis | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Esophagus | Squamous epithelial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced IARS1 IHC Tips
Troubleshoot IARS1 staining in paraffin sections by checking retrieval, cytoplasmic localisation, controls and cell-specific scoring (UniProt P41252 localisation; HPA tissue IHC).
Which retrieval condition should I try first for weak IARS1 staining?
Start with heat-mediated retrieval in EDTA at pH 8.0 for paraffin sections (datasheet A06805-1). After deparaffinization, compare 10–20 minutes of heating on adjacent sections while holding section thickness and detection conditions constant (standard IHC practice). Use 2 μg/ml primary antibody overnight at 4°C as the documented staining reference (caption A06805-1). If staining remains weak, test citrate at pH 6.0 as a fallback alongside EDTA, checking tissue morphology and background (standard IHC practice). Judge improvement by clearer cytoplasmic staining, rather than darker DAB alone (UniProt P41252 localisation; standard IHC practice).
How should I investigate possible fixation-related loss of IARS1 staining?
The paraffin-section caption does not report a fixative, so target-specific fixation sensitivity is unknown (caption A06805-1). Record the fixative, time to fixation and fixation duration for each specimen before comparing staining intensity (standard IHC practice). If handling varies, stain adjacent sections together using EDTA at pH 8.0 and the same antibody concentration (datasheet A06805-1; standard IHC practice). Compare preserved cellular morphology and cytoplasmic signal against a similarly processed positive control, without treating a negative result as proof of absent protein (UniProt P41252 localisation; standard IHC practice). Do not infer fixation tolerance from tissue-expression patterns or protein topology (HPA tissue IHC; UniProt P41252 topology).
Should I score nuclear or membrane staining as IARS1 positive?
Prioritise cytoplasmic staining: IARS1 is annotated in the cytoplasm and cytosol, with no transmembrane segment or signal peptide (UniProt P41252 localisation and topology). Cytosolic localisation is supported in subcellular imaging, whereas the reported nucleoplasmic location is uncertain (HPA subcellular). Assess the nuclear boundary against a counterstain before assigning any nuclear signal to IARS1 (standard IHC practice). If staining is predominantly membranous or nuclear, compare an adjacent section stained without primary antibody and repeat retrieval under the documented EDTA pH 8.0 condition (datasheet A06805-1; standard IHC practice). Report unexpected compartments separately from cytoplasmic scores (UniProt P41252 localisation; standard IHC practice).
Could an isoform or modified epitope explain inconsistent staining?
The supplied record annotates 0 isoforms and one 1–1262 chain, so an isoform-specific interpretation lacks support here (UniProt P41252 processing and isoforms). It lists phosphorylation at residues 1047, 1049 and 1058, but the antibody epitope is unspecified (UniProt P41252 modified residues; caption A06805-1). Therefore, do not attribute staining differences to those modifications without epitope mapping and an independent validation experiment (standard IHC practice). Compare serial sections processed with identical EDTA pH 8.0 retrieval and detection before investigating epitope accessibility (datasheet A06805-1; standard IHC practice). Record any alternative antibody's immunogen and staining compartment when interpreting discordance (standard IHC practice).
How can IF help check an ambiguous chromogenic IARS1 result?
Use IF as a separate localisation check, since the supplied catalog-antibody caption documents chromogenic paraffin-section IHC (caption A06805-1). In lung, multiplex IARS1 with a macrophage marker such as CD68 and compare cytosolic signal within identified cells (HPA: High in macrophages; standard IF practice). Choose a far-red fluorophore when tissue autofluorescence compromises shorter wavelengths, and include single-channel controls (standard IF practice). Permeabilise sufficiently to expose a cytosolic epitope, then titrate detergent to preserve cell boundaries; IARS1 has no annotated transmembrane segment (UniProt P41252 topology; standard IF practice). Establish IF fixation and antibody conditions independently because the IHC caption does not state the fixative or validate IF (caption A06805-1).
What should I change when DAB background obscures cytoplasmic staining?
First inspect a section processed without primary antibody to identify secondary-reagent or chromogen background (standard IHC practice). The documented paraffin-section method used 10% goat serum, 2 μg/ml primary antibody overnight at 4°C, and HRP with DAB (caption A06805-1). If diffuse staining persists, titrate the primary concentration and blocking conditions while preserving the EDTA pH 8.0 retrieval reference (datasheet A06805-1; standard IHC practice). Include a peroxidase-blocking step and check whether pigment or tissue edges retain DAB independently of specific binding (standard IHC practice). Accept a change only when cytoplasmic contrast improves without losing cellular detail (UniProt P41252 localisation; standard IHC practice).
How should I quantify IARS1 across tissues with different cell populations? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and scoring area before comparing slides, because reported staining differs among tissue cell types (HPA tissue IHC; standard IHC practice). Score cytoplasmic intensity and percentage of positive cells, then calculate an H-score from the intensity categories used consistently throughout the study (UniProt P41252 localisation; standard IHC practice). For sparse populations, report positive cells per mm² and normalise to the number of eligible cells or viable tissue area (standard IHC practice). Exclude folds, necrosis and section edges using the same rule for every slide (standard IHC practice). Keep retrieval, chromogen development and image thresholds constant across compared specimens (standard IHC practice).
How can I distinguish true IARS1 staining from artefact?
A credible signal should be predominantly cytoplasmic within intact cells, consistent with the supported cytosolic location (UniProt P41252 localisation; HPA subcellular). Cell identity matters: lung macrophages show high staining, whereas normal esophageal squamous epithelial cells were reported as not detected (HPA: High in lung macrophages; HPA: Not detected in esophagus squamous epithelial cells). The selected carcinoma caption demonstrates staining in a paraffin section but does not establish the pattern expected in normal esophagus (caption A06805-1; HPA tissue IHC). Treat edge enhancement, necrotic deposits or staining reproduced without primary antibody as possible artefacts (standard IHC practice). Interpret discordant results cautiously because tissue IHC has low consistency with RNA expression (HPA tissue IHC).
Boster reagents
Best IARS1 / Isoleucine--tRNA ligase, cytoplasmic IHC Antibodies
A06805-1 has real IHC data from human paraffin sections; no IF/ICC data are supplied (A06805-1 catalog reactivity, applications, and image captions).
Real IHC data
Anti-IARS1 Antibody ®
Cat # A06805-1
A06805-1 is listed for human IHC, with paraffin-section images from human esophageal squamous carcinoma, liver cancer, and lung cancer (A06805-1 catalog and image captions). No IF/ICC validation or figure is listed for A06805-1 (A06805-1 catalog applications and IF image alts).
Which to pick: Choose A06805-1 for human paraffin-section IHC: its image caption documents EDTA pH 8.0 retrieval and 2 μg/ml primary antibody, within the catalog’s 2–5 μg/ml IHC range (A06805-1 image caption; catalog dilution). The fixative is unreported (A06805-1 image caption). No listed SKU supports an IF/ICC or cross-species recommendation: A06805-1 lists human reactivity and IHC, but no IF/ICC application or IF figure (A06805-1 catalog applications, reactivity, and IF image alts).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P41252 (SYIC_HUMAN, Isoleucine--tRNA ligase, cytoplasmic).
- Human Protein Atlas. IARS1 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. IARS1 subcellular location (ICC-IF): Localized to the nucleoplasm and cytosol..
- Human Protein Atlas. IARS1 antibody validation summary (1 antibodies).
- Isoleucyl-tRNA synthetase 1 mutation impairs pulmonary surfactant homeostasis by disrupting alveolar macrophage function. Respiratory research 2026 — PMC13584253.
- PubMed PMID:8052601 — UniProt-cited evidence.
- PubMed PMID:7721108 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for IARS1 (Isoleucine--tRNA ligase, cytoplasmic). Expected localisation Cytoplasmic staining in several tissues (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A06805-1). Validated IHC antibody: A06805-1 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Cerebellum (Purkinje cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human esophageal squamous carcinoma tissue; fixative not specified (datasheet A06805-1); 2. Fixation: Image fixative and duration unreported (datasheet A06805-1); 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 retrieval: EDTA pH 8.0 (datasheet A06805-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A06805-1); 8. Primary antibody: Rabbit anti-IARS1, 2-5 μg/ml (datasheet A06805-1); 9. Primary incubation: Overnight at 4 °C (datasheet A06805-1). Watch for: Fixation: Keep fixation consistent across paraffin sections (standard IHC practice; not target-specific); Caveat: Staining has low consistency with RNA expression (HPA tissue IHC); Isoform / epitope: No annotated isoforms or propeptide; one chain (UniProt); Regulation: Low tissue specificity at RNA level (HPA tissue RNA). Evidence: UniProt P41252, HPA tissue IHC · Approved, HPA ICC-IF · nucleoplasm and cytosol., Datasheet A06805-1, PMC13584253. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/IARS1/immunohistochemistry-ihc-guide.