NAA11 Antibody
Description
Definition and Biological Context
NAA11 Antibody is an affinity-isolated polyclonal antibody raised against the human NAA11 protein, a homolog of the catalytic subunit NAA10 in the NatA acetyltransferase complex . NAA11 (also known as ARD1B or ARD2) shares structural similarities with NAA10 but exhibits distinct tissue-specific expression patterns, primarily localized to testis and placenta . The antibody enables researchers to investigate NAA11's role in protein N-terminal acetylation, epigenetic regulation, and disease mechanisms.
Tissue-Specific Expression
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NAA11 is undetectable in most human tissues except testis and placenta, contrasting with the ubiquitous expression of NAA10 .
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Hypermethylation of the NAA11 promoter suppresses its transcription in non-expressing tissues, as shown via methylation-specific PCR and bisulfite sequencing .
Cancer Research Insights
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NAA11 re-expression in cancers (e.g., hepatocellular carcinoma) correlates with improved prognosis, suggesting tumor-suppressive potential .
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Loss of heterozygosity in NAA11 is linked to poor clinical outcomes in liver cancer .
Functional Redundancy
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NAA11 and NAA10 may exhibit partial functional overlap, but compensation is restricted due to NAA11’s limited expression .
Applications
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Immunohistochemistry (IHC): Maps NAA11 expression in normal and cancerous tissues (e.g., Human Protein Atlas) .
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Epigenetic Studies: Investigates DNA methylation’s role in silencing NAA11 in non-gonadal tissues .
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Cancer Biomarker Research: Evaluates NAA11’s diagnostic or prognostic value in malignancies .
Future Directions
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Elucidate NAA11’s substrate specificity compared to NAA10.
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Explore therapeutic strategies targeting NAA11 methylation in cancers.
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Expand validation in understudied cancer types using multi-omics approaches.
Product Specs
Target Background
- NAA11 expression is tissue-specific and is epigenetically regulated by DNA methylation. PMID: 22048246
- ARD1 protein was observed at 61.0% (50/82), 54.7% (87/159), 37.9% (25/66), and 36.8% (7/19) in invasive ductal carcinoma (IDC), fibroadenoma, hyperplasia, and inflammation, respectively. PMID: 22292636
- hARD2, an N-alpha-acetyltransferase, shares 81% sequence identity with hARD1. Its gene may have originated from a eutherian-mammal-specific retrotransposition event. hARD2-NATH complexes may be responsible for protein N-alpha-acetylation in human cells. PMID: 16638120
- hARD2 (MGC10646) is a novel human protein N-alpha acetyltransferase. PMID: 16638120
Q&A
What is the biological role of NAA11, and how does its tissue specificity influence experimental workflows?
NAA11 (N-alpha-acetyltransferase 11) is a catalytic subunit of the NatA complex, which mediates N-terminal acetylation of nascent polypeptides. Unlike its paralog NAA10, which is ubiquitously expressed, NAA11 exhibits strict tissue specificity, with robust expression confined to the testis and placenta in humans . This restricted expression is epigenetically regulated by CpG island methylation in its promoter . For researchers, this necessitates:
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Tissue selection: Prioritize gonadal or placental samples for protein detection.
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Methylation analysis: Use methylation-specific PCR (MS-PCR) or bisulfite sequencing to assess promoter methylation status in non-expressing tissues .
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Controls: Include testis-derived lysates as positive controls in western blotting (WB) or immunohistochemistry (IHC).
Table 1: NAA11 Expression Across Human Tissues (RT-PCR Data)
| Tissue | NAA10 Expression | NAA11 Expression | Methylation Status |
|---|---|---|---|
| Testis | High | High | Partially methylated |
| Placenta | High | Low | Partially methylated |
| Liver | High | Absent | Hypermethylated |
| Lung | High | Absent | Hypermethylated |
What are the primary challenges in detecting NAA11 protein in non-gonadal tissues?
NAA11 is undetectable in most somatic tissues due to promoter hypermethylation . Key methodological considerations include:
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Antibody cross-reactivity: Many commercial NAA11 antibodies (e.g., Novus Biologicals NBP1-90853) cross-react with NAA10 due to ~62% sequence homology . Validate specificity using:
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Transcript vs. protein discordance: While low-level NAA11 mRNA may occur in cancer tissues (e.g., liver, ovary), translational repression often prevents protein expression . Confirm via parallel RT-PCR and WB.
Stepwise Validation Protocol:
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Immunogen alignment: Use antibodies raised against unique epitopes (e.g., NAA11 C-terminal peptide DELRRQMDLKKGGYVVLGSR ).
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KO validation: Test antibodies in NAA11-KO models (e.g., CRISPR-edited cell lines) .
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Protein array screening: Verify lack of cross-reactivity against 384 non-target proteins (e.g., Atlas Antibodies HPA035922) .
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Dual detection: Pair IHC with RNA in situ hybridization to confirm transcriptional activity correlates with protein signal .
Table 2: Antibody Performance Comparison
| Antibody Vendor | Host | Epitope Region | Cross-Reactivity Tested | Applications Validated |
|---|---|---|---|---|
| Novus Biologicals | Rabbit | DELRRQMDLKKGGYVVLGSR | Protein array (384 antigens) | IHC, IF, WB |
| Atlas Antibodies | Rabbit | C-terminal peptide | IHC on 44 normal tissues | IHC-P, IF |
| Cell Signaling Tech | Rabbit | NAA10-specific (Asp204) | Naa12 KO mice | WB, IP |
What experimental strategies address discrepancies in NAA11 expression across studies?
Conflicting reports of NAA11/NAA10 co-expression arise from:
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Cell line variability: HeLa cells show partial NAA11 promoter demethylation, enabling low-level expression absent in other lines .
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Antibody lot variability: Commercial batches may differ in cross-reactivity (e.g., Abcam vs. Cell Signaling Tech antibodies) .
Resolution workflow:
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Methylation profiling: Perform bisulfite sequencing on cell lines/tissues to confirm promoter status .
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Orthogonal assays: Combine RNA-seq, WB, and enzymatic assays (e.g., acetyltransferase activity using γ-actin peptides) .
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Inter-laboratory replication: Share reagents (e.g., plasmids, lysates) to standardize detection protocols.
How does NAA11’s epigenetic regulation inform disease models?
NAA11 repression in cancers correlates with promoter hypermethylation . To study this:
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Demethylation agents: Treat cell lines with 5-aza-2′-deoxycytidine (5-Aza-dC) and monitor re-expression via qPCR .
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Luciferase reporter assays: Clone the NAA11 promoter (e.g., -427 bp to +7 codons) into pGL3-Basic and test methylation-dependent activity .
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Clinical correlation: Analyze TCGA datasets for NAA11 methylation vs. survival in testicular/placental cancers.
What functional redundancy exists between NAA11 and other NatA subunits?
While NAA11 and NAA10 share catalytic roles, NAA12 (a newly identified paralog) compensates for NAA10 in murine models . Key implications:
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Knockout studies: Dual NAA10/NAA12 KO causes embryonic lethality in mice, unlike single KOs .
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Substrate specificity: NAA11 acetylates acidic N-termini (e.g., DDDIA-), while NAA12 prefers similar motifs but shows distinct tissue expression .
Experimental Design Tip:
Use NatA complex immunoprecipitation (e.g., anti-NAA15 antibodies) to determine if NAA11 integrates into the ribosome-associated complex .
