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MAP4K1 / Mitogen-activated protein kinase kinase kinase kinase 1 · IHC design guide
Design Immunohistochemistry for MAP4K1
Plan paraffin-section MAP4K1 IHC with lymphoid tissue controls and a cytoplasmic staining expectation (HPA tissue IHC). The guide covers fixation consistency, antigen retrieval, antibody dilution, chromogenic detection, and interpretation of possible off-target staining (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
MAP4K1 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 lymphoid tissue (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic staining in germinal center cells (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A07909-3) | |
| Positive control | Bone marrow+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 conditions consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | Presumed off-target staining has been observed (HPA tissue IHC) | |
| Regulation | Primarily expressed in hematopoietic organs (UniProt) | |
| Isoform / epitope | Two isoforms; confirm antibody epitope coverage (UniProt) |
Section 1
Recommended MAP4K1 IHC & IF Protocols
The catalog antibody protocol uses EDTA pH 8.0 retrieval (datasheet A07909-3); the three published MAP4K1 IHC protocols below provide sample-specific alternatives (PMC10514360; PMC11472321; PMC6491656).
| Sample | Paraffin-embedded human colonic adenocarcinoma tissue; fixative not specified (datasheet A07909-3) |
| Fixation | Image fixative and duration unreported (datasheet A07909-3); 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 A07909-3); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A07909-3) |
| Primary antibody | Rabbit anti-MAP4K1, 2-5 μg/ml (datasheet A07909-3) |
| Primary incubation | Overnight at 4 °C (datasheet A07909-3) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A07909-3) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | MAP4K1-positive staining in hematopoietic cells of bone marrow (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in lymphoid tissues. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 for the catalog antibody (datasheet A07909-3); consider the published citrate or pH 9 conditions when optimizing retrieval (PMC10514360; PMC11472321; PMC6491656).
Section 2
What Is the Expected MAP4K1 Staining Pattern?
MAP4K1 staining in paraffin-section IHC is expected mainly in the cytoplasm of lymphoid and hematopoietic cells (HPA: tissue IHC profile). Bone marrow hematopoietic cells and lymph node and tonsil germinal center cells show high staining (HPA: tissue IHC). MAP4K1 has no transmembrane segment (UniProt Q92918: topology). HPA rates the tissue profile Enhanced, with medium consistency between antibody staining and RNA data and presumed off-target staining disregarded (HPA: reliability description).
| Cytoplasmic staining in bone marrow hematopoietic cells or lymph node and tonsil germinal center cells. | This matches the expected positive pattern; HPA reports high staining in those cell populations (HPA: tissue IHC). Judge the labeled cells and their compartment against the section’s morphology, rather than treating every cell in a positive tissue as positive (general IHC interpretation). |
| Cytoplasmic staining in appendix germinal center cells or spleen white-pulp cells. | A moderate signal can fit the reference pattern: both populations are reported at medium staining, below the high-staining populations listed above (HPA: tissue IHC). Compare comparable cell populations when judging intensity (general IHC interpretation). |
| Predominantly nuclear staining, with little staining in the expected cytoplasmic compartment. | This conflicts with the reported cytoplasmic tissue-IHC profile (HPA: tissue IHC). Treat it as a possible artifact or nonspecific result and inspect morphology and controls before assigning it to MAP4K1 (general IHC interpretation). |
| Strong staining in adipocytes or respiratory epithelial cells while expected lymphoid cells are unstained. | HPA reports no detection in adipose-tissue adipocytes or bronchial respiratory epithelial cells (HPA: tissue IHC). Consider off-target antibody binding or endogenous chromogenic activity; HPA’s reliability note acknowledges presumed off-target staining (HPA: reliability description; general IHC practice). |
| Diffuse color across tissue, or no signal in a bone marrow or tonsil positive control. | Diffuse color without a recognizable cell pattern is difficult to score as specific staining (general IHC interpretation). A blank expected positive control prevents a reliable negative call on test sections; bone marrow and tonsil contain high-staining populations (HPA: tissue IHC). |
💡Expected MAP4K1 appearanceCall a result positive when chromogenic signal is chiefly cytoplasmic in the appropriate hematopoietic or germinal center cells, with high staining in bone marrow, lymph node or tonsil reference populations; isolated nuclear, diffuse or discordant cell-type staining warrants review (HPA: tissue IHC; general IHC interpretation).
| Tissue and cell population | Expression is concentrated in hematopoietic organs (UniProt Q92918: tissue specificity). HPA reports high staining in bone marrow hematopoietic cells and lymph node and tonsil germinal center cells, and medium staining in appendix germinal centers and spleen white pulp (HPA: tissue IHC). |
| Antibody validation and specificity | Both listed antibodies, HPA007419 and CAB007754, have Enhanced IHC status (HPA: antibodies). The overall tissue profile has medium agreement with RNA data, and presumed off-target binding was disregarded; a labeled cell outside the reference pattern still needs scrutiny (HPA: reliability description). |
| Compartment and protein architecture | The tissue-IHC profile is cytoplasmic (HPA: tissue IHC). UniProt lists no transmembrane segment or signal peptide for MAP4K1 (UniProt Q92918: topology, processing). These features do not establish a target-specific antigen-retrieval or fixation effect (UniProt Q92918: record scope). |
| Isoforms and epitope coverage | UniProt lists two MAP4K1 isoforms (UniProt Q92918: isoforms). The supplied evidence gives no epitope location or isoform coverage for the catalog antibody, so an isoform-specific staining difference cannot be predicted from this record (UniProt Q92918: record scope). |
| IF/ICC Q&A | Q: Should membrane staining in IF/ICC change the paraffin-IHC expectation? A: HPA reports an approved plasma-membrane location in ICC-IF, while its tissue-IHC profile is cytoplasmic (HPA: subcellular; HPA: tissue IHC). Interpret each assay against its own reported pattern; the supplied sources do not explain the difference. |
| Situation | Likely cause | Next action |
|---|---|---|
| No chromogenic signal in a test section or expected positive control. | The run has not demonstrated detection in a population reported as high staining (HPA: bone marrow, lymph node and tonsil tissue IHC). Tissue content or a general staining-workflow failure may be responsible (general IHC practice). | Confirm that the positive-control section contains the expected cells; check antibody application, detection reagents and control performance before calling the test tissue negative (general IHC practice). |
| Signal appears mainly nuclear. | Nuclear dominance differs from the cytoplasmic tissue-IHC profile (HPA: tissue IHC). Counterstain overlap or nonspecific staining can complicate compartment calls (general IHC interpretation). | Review the counterstain and cell boundaries at higher magnification; compare the expected cytoplasmic positive-control cells and appropriate negative controls (general IHC practice). |
| Strong color appears in adipocytes or bronchial respiratory epithelium. | Those populations are reported as not detected (HPA: tissue IHC). Off-target binding is plausible given HPA’s reliability note; endogenous chromogenic activity is another general IHC possibility (HPA: reliability description; general IHC practice). | Check no-primary and detection controls, then compare staining with the expected hematopoietic or germinal-center pattern before scoring it as MAP4K1 (general IHC practice; HPA: tissue IHC). |
| Color is diffuse across the section, with poor cell-level definition. | Background from the staining or detection workflow can obscure compartment and cell-type assessment (general IHC practice). The HPA reference pattern requires recognizable cytoplasmic staining in lymphoid cells (HPA: tissue IHC). | Inspect control sections and review blocking, washing, antibody concentration and chromogen development as general IHC workflow variables; reassess only where cell boundaries remain clear (general IHC practice). |
| Spleen or appendix staining looks weaker than tonsil or lymph node. | HPA rates spleen white-pulp cells and appendix germinal-center cells medium, versus high in tonsil and lymph node germinal-center cells (HPA: tissue IHC). | Score the relevant cell populations against their tissue-specific reference levels; use a high-staining reference population to confirm the run if the result remains uncertain (HPA: tissue IHC; general IHC practice). |
| The catalog antibody stains a region outside the expected tissue pattern. | Enhanced IHC status supports the reference pattern, but does not make every observed signal specific; HPA reports medium staining–RNA consistency and disregarded presumed off-target binding (HPA: antibodies; HPA: reliability description). | Document the affected cell type and compartment, compare the tissue-IHC reference and controls, and withhold a MAP4K1-positive call if the discordance persists (HPA: tissue IHC; general IHC interpretation). |
Experiment evidence
IHC & IF images showing MAP4K1 staining
A07909-3 · IHCIHC analysis of MAP4K1/HPK1 using anti-MAP4K1/HPK1 antibody (A07909-3). MAP4K1/HPK1 was detected in a paraffin-embedded section of human col
A07909-3 · IHCIHC analysis of MAP4K1/HPK1 using anti-MAP4K1/HPK1 antibody (A07909-3). MAP4K1/HPK1 was detected in a paraffin-embedded section of human gal
A30542 · IHCImmunohistochemical analysis of paraffin-embedded Human breast cancer. Antibody was diluted at 1:100(4° overnight). High-pressure and temper
M07909 · IHCImmunohistochemical analysis of paraffin-embedded human epityphlon tissue using M07909 performed on the vendor® BOND RXm. Samples were incub
M07909 · IHCImmunohistochemical analysis of paraffin-embedded human tonsil tissue using M07909 performed on the vendor® BOND RXm. Samples were incubated
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000104814-MAP4K1/tissue/cerebral+cortex#imid_2274532
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000104814-MAP4K1/tissue/colon#imid_2274458
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000104814-MAP4K1/tissue/liver#imid_2274451
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000104814-MAP4K1/tissue/kidney#imid_2274452
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB007754; green = MAP4K1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB007754; green = MAP4K1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for MAP4K1 IHC & IF
🧪Run bone marrow first: hematopoietic cells should stain (HPA: High in bone marrow hematopoietic cells). Use adipose tissue as a negative, assessing adipocytes (HPA: Not detected in adipocytes); on the bone marrow slide, assess morphologically identified nonhematopoietic cells as internal negative comparators rather than expecting every cell to stain (HPA: High is assigned to hematopoietic cells).
Positive control tissue: Bone marrow (Hematopoietic cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show MAP4K1 in A-431, U2OS, with annotated localisation: Plasma membrane (approved) (HPA subcellular).
Technical controls: Include no-primary (secondary-only) and matched rabbit IgG isotype controls (caption: rabbit primary antibody; standard IHC practice), plus MAP4K1-knockout tissue as a biological specificity control (standard IHC practice). For chromogenic detection in bone marrow, block endogenous peroxidase and check for endogenous biotin when using the caption’s biotin-based detection system (caption: biotinylated secondary and SABC; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected A07909-3 tissue-IHC caption does not state a fixative (caption: fixative not stated). The paraffin-section example uses heat retrieval in EDTA at pH 8.0, but the supplied evidence does not establish that MAP4K1 staining depends on that retrieval condition (caption: EDTA retrieval). Whether frozen sections or IF are easier is unreported; in bone marrow, endogenous peroxidase and biotin can complicate chromogenic interpretation (caption: SABC/DAB detection; standard IHC practice).
HPA tissue IHC evidence for MAP4K1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — Medium consistency between antibody staining and RNA expression data. Presumed off target binding observed and disregarded.). 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 |
|---|---|---|---|---|
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Lymph node | Germinal center cells | High | Protein (IHC) | HPA → |
| Tonsil | Germinal center cells | High | Protein (IHC) | HPA → |
| Appendix | Germinal center cells | Medium | Protein (IHC) | HPA → |
| Spleen | Cells in white pulp | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced MAP4K1 IHC Tips
Troubleshoot MAP4K1 staining in paraffin sections using the catalog antibody’s tissue protocol and cell-specific controls.
Which retrieval condition should I start with for MAP4K1 paraffin-section IHC?
Start with heat-mediated retrieval in EDTA at pH 8.0 (datasheet A07909-3). The documented tissue example then uses 10% goat serum blocking and 2 μg/ml primary antibody overnight at 4°C (datasheet A07909-3). If staining is weak, compare a modest range of heating durations on adjacent sections while holding antibody concentration and detection constant (standard IHC practice). Judge the result in hematopoietic cells or lymphoid germinal centers, where staining is reported as high (HPA: bone marrow and lymph node). Watch for stronger tissue-edge staining, which can reflect uneven retrieval rather than antigen distribution (standard IHC practice).
How should I troubleshoot fixation when MAP4K1 staining is weak?
MAP4K1-specific sensitivity to fixation is unknown: the selected paraffin-section caption does not state a fixative (datasheet A07909-3). Record the specimen’s actual fixative and fixation duration, then compare sections processed under documented conditions before attributing weak staining to fixation (standard IHC practice). Keep EDTA retrieval at pH 8.0 and the primary antibody at 2 μg/ml overnight at 4°C during that comparison (datasheet A07909-3). Include a lymphoid or bone-marrow positive control in the same staining run (HPA: high staining in lymph-node germinal center cells and bone-marrow hematopoietic cells). Excessive or uneven fixation can impair IHC staining generally, but no MAP4K1-specific threshold is established here (standard IHC practice; datasheet A07909-3).
Should MAP4K1 look cytoplasmic or membrane-associated in my sections?
In tissue IHC, cytoplasmic expression is reported in lymphoid tissues (HPA: tissue IHC profile). Plasma-membrane localisation is separately reported from subcellular ICC/IF images, so assess membrane-associated staining against the tissue pattern and cell identity (HPA: subcellular; HPA: tissue IHC profile). MAP4K1 has no annotated transmembrane segment, and UniProt does not assign a subcellular location (UniProt Q92918 topology and subcellular record). Compare germinal center cells with nearby structures on the same section, using the 2 μg/ml catalog-antibody condition as a documented starting point (HPA: high in lymph-node germinal center cells; datasheet A07909-3). Diffuse staining of every cell type calls for background checks before a localisation claim (standard IHC practice).
Can this staining distinguish MAP4K1 isoforms or phosphorylation states?
MAP4K1 has 2 listed isoforms and contains a protein-kinase domain at residues 17–274 and a CNH domain at 495–800 (UniProt Q92918). Autocatalytic phosphorylation is annotated at residues including 165, 171 and 175 (UniProt Q92918 modified residues). The supplied catalog caption identifies neither the antibody epitope nor phospho-selectivity, so its IHC signal cannot by itself assign an isoform or phosphorylation state (datasheet A07909-3). Check epitope documentation before choosing an orthogonal antibody, and interpret discordant staining in light of epitope accessibility after EDTA retrieval at pH 8.0 (standard IHC practice; datasheet A07909-3). Keep any isoform or phospho-specific conclusion conditional on a separately validated reagent and control (standard IHC practice).
How can I adapt the MAP4K1 assessment to multiplex IF?
Pair MAP4K1 with a validated hematopoietic-cell marker to identify the stained population, since bone-marrow hematopoietic cells show high tissue-IHC staining (HPA: bone marrow). Include a single-stain control for each fluorophore and choose channels after examining tissue autofluorescence, particularly where its emission overlaps the proposed signal (standard IF practice). HPA reports plasma-membrane localisation in ICC/IF images, whereas its tissue-IHC profile is cytoplasmic in lymphoid tissues (HPA: subcellular; HPA: tissue IHC profile). Because MAP4K1 lacks a transmembrane segment, select permeabilisation according to the mapped antibody epitope and validate access empirically; that epitope is unspecified here (UniProt Q92918 topology; datasheet A07909-3). Do not carry the paraffin-section retrieval condition into IF without testing it in the chosen preparation (standard IF practice; datasheet A07909-3).
What should I check when MAP4K1 DAB staining is widespread?
First compare the slide with a no-primary control and inspect whether colour tracks tissue edges, folds or damaged areas (standard IHC practice). The documented detection uses a biotinylated secondary, streptavidin–biotin complex and DAB, so assess background from endogenous biotin and peroxidase as part of this workflow (datasheet A07909-3; standard IHC practice). Apply a peroxidase block and verify the detection-only control before raising the primary above 2 μg/ml (standard IHC practice; datasheet A07909-3). Use 10% goat serum blocking as the documented starting condition, with matched washes and development across comparison sections (datasheet A07909-3; standard IHC practice). Widespread strong signal in cells reported as undetected deserves scrutiny because the HPA tissue assessment notes presumed off-target binding (HPA: negative tissue list and reliability description).
How should I score MAP4K1 across lymphoid and tumour sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell compartment before scoring: germinal center cells are reported high, while spleen white-pulp cells are reported medium (HPA: tissue IHC). For a comparable cell population, report the percentage of positive cells and an intensity-weighted H-score, using the same threshold and DAB development settings across slides (standard IHC practice). If the question concerns infiltrates, report positive-cell density per mm² of viable tissue and normalise to the corresponding hematopoietic-cell count (standard IHC practice; UniProt Q92918 tissue specificity). Exclude necrosis and tissue edges from the scored area, and document which cells and areas were counted (standard IHC practice). The demonstrated colonic adenocarcinoma image establishes a staining example, not a numerical expression baseline for all tumour cells (datasheet A07909-3).
How do I distinguish credible MAP4K1 staining from artefact?
Give greatest weight to signal in hematopoietic or lymphoid cells: high staining is reported in bone marrow and germinal centers, and UniProt describes predominantly hematopoietic expression (HPA: tissue IHC; UniProt Q92918 tissue specificity). Cytoplasmic lymphoid staining fits the tissue-IHC profile; an exclusively nuclear pattern requires independent confirmation (HPA: tissue IHC profile; standard IHC practice). Check suspicious signal at section edges, in necrosis or across unrelated cell types against a no-primary control (standard IHC practice). With DAB and streptavidin–biotin detection, evaluate endogenous peroxidase and biotin when staining persists without primary antibody (datasheet A07909-3; standard IHC practice). Treat isolated unexpected staining cautiously because the HPA reliability assessment records presumed off-target binding (HPA: reliability description).
Boster reagents
Best MAP4K1 / Mitogen-activated protein kinase kinase kinase kinase 1 IHC Antibodies
Three human-reactive antibodies have paraffin-section IHC images (catalog captions); A30542 also lists mouse reactivity and IF/ICC applications (catalog applications/reactivity).
Real IHC data
Anti-MAP4K1/HPK1 Antibody ®
Cat # A07909-3
Real IHC data
Anti-MEKKK 1 Antibody
Cat # A30542
Real IHC data
Anti-MAP4K1 Antibody
Cat # M07909
A07909-3 has IHC images of human colonic adenocarcinoma and gall bladder adenosquamous carcinoma paraffin sections; A30542 has an IHC image of human breast cancer paraffin tissue (catalog image captions). M07909 has IHC images of human epityphlon and tonsil paraffin sections (catalog image captions).
Which to pick: For human paraffin-section IHC, choose A07909-3 for the documented EDTA pH 8 retrieval and 2 μg/ml overnight staining with DAB detection, or rabbit polyclonal M07909 for its documented automated 1:500 IHC protocol (A07909-3 and M07909 image captions; M07909 catalog dilution_raw). For IF/ICC or a human- and mouse-reactive option, choose rabbit polyclonal A30542, which lists those applications and species; its IHC image shows human breast cancer paraffin tissue, while no IF image is supplied (A30542 catalog applications/reactivity/dilution_raw and image captions). The fixative is unreported for all three IHC examples (catalog image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q92918 (M4K1_HUMAN, Mitogen-activated protein kinase kinase kinase kinase 1).
- Human Protein Atlas. MAP4K1 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. MAP4K1 subcellular location (ICC-IF): Localized to the plasma membrane..
- Human Protein Atlas. MAP4K1 antibody validation summary (2 antibodies).
- Glioblastoma cellular MAP4K1 facilitates tumor growth and disrupts T effector cell infiltration. Life science alliance 2023 — PMC10514360.
- Discovery of BAY-405: An Azaindole-Based MAP4K1 Inhibitor for the Enhancement of T-Cell Immunity against Cancer. Journal of medicinal chemistry 2024 — PMC11472321.
- PDIA6 modulates apoptosis and autophagy of non-small cell lung cancer cells via the MAP4K1/JNK signaling pathway. EBioMedicine 2019 — PMC6491656.
- PubMed PMID:8824585 — UniProt-cited evidence.
- PubMed PMID:15057824 — UniProt-cited evidence.
- PubMed PMID:19369195 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for MAP4K1 (Mitogen-activated protein kinase kinase kinase kinase 1). Expected localisation Cytoplasmic staining in lymphoid tissue (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A07909-3). Validated IHC antibody: A07909-3 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Bone marrow (Hematopoietic cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human colonic adenocarcinoma tissue; fixative not specified (datasheet A07909-3); 2. Fixation: Image fixative and duration unreported (datasheet A07909-3); 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 A07909-3); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A07909-3); 8. Primary antibody: Rabbit anti-MAP4K1, 2-5 μg/ml (datasheet A07909-3); 9. Primary incubation: Overnight at 4 °C (datasheet A07909-3). Watch for: Fixation: Keep fixation conditions consistent across sections (standard IHC practice; not target-specific); Caveat: Presumed off-target staining has been observed (HPA tissue IHC); Isoform / epitope: Two isoforms; confirm antibody epitope coverage (UniProt); Regulation: Primarily expressed in hematopoietic organs (UniProt). Evidence: UniProt Q92918, HPA tissue IHC · Enhanced, HPA ICC-IF · plasma membrane., Datasheet A07909-3, PMC10514360, PMC11472321. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/MAP4K1/immunohistochemistry-ihc-guide.