ETNK2 Human
Description
Introduction to ETNK2 Human
ETNK2 (ethanolamine kinase 2) is a protein-coding gene located on human chromosome 1q32.1. It encodes an enzyme in the choline/ethanolamine kinase family, which catalyzes the phosphorylation of ethanolamine—the first step in synthesizing cytidine diphosphate ethanolamine (CDP-ethanolamine), a precursor for phosphatidylethanolamine (PE), a critical phospholipid in cellular membranes . ETNK2 is ubiquitously expressed across human tissues, with higher activity noted in renal tubules, seminiferous ducts, and thyroid cells .
Key Features:
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Gene Structure: 11 splice variants, with ENST00000367202.9 (386 amino acids) as the canonical isoform .
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Domains: Contains a protein kinase-like domain superfamily (IPR011009) .
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Pathway Involvement:
Research Findings:
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↓ Neutrophil infiltration; ↑ Th1 cell suppression . |
| Functional Enrichment | Associated with xenobiotic metabolism and small-molecule catabolism .
Clinical and Mechanistic Insights:
Functional Roles:
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Proliferation: Silencing ETNK2 reduced TPC-1 and BCPAP cell viability by 40–60% (p < 0.01) .
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Metastasis: Knockdown decreased migration/invasion via EMT suppression (↑ E-cadherin, ↓ N-cadherin) .
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Pathway Activation: Modulates HIPPO (YAP/TAZ) and EMT pathways .
Mechanistic Insights from Enrichment and Pathway Analyses
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Differentially Expressed Genes (DEGs): In KIRC, ETNK2 dysregulation affects metabolic pathways (e.g., amino acid degradation) .
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Single-Cell Analysis: Predominant expression in kidney capillary endothelial cells .
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Protein Interaction Networks: Associates with metabolic enzymes (e.g., PCYT2) and immune checkpoint regulators (e.g., PD-L1) .
Immune Microenvironment Interactions
ETNK2 expression influences tumor-infiltrating lymphocytes (TILs):
| Immune Metric | Correlation |
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| Neutrophils | Moderate positive (r = 0.32) . |
| Th1 Cells | Strong negative (r = -0.47) . |
| Immune Checkpoints | Downregulation linked to reduced CTLA4 and LAG3 . |
Predicted 3D Structure (AlphaFold):
Clinical Implications and Future Directions
Product Specs
Ethanolaminekinase-2
Q&A
What is ETNK2 and what is its primary function in human cells?
ETNK2 (also known as EKI2 or HMFT1716) is a 386 amino acid protein belonging to the choline/ethanolamine kinase family. Its primary function is catalyzing the initial step of phosphatidylethanolamine (PtdEtn) biosynthesis through the cytidine diphosphate (CDP) ethanolamine pathway . This enzyme is highly specific for ethanolamine phosphorylation and plays a crucial role in phospholipid metabolism, which is essential for membrane structure and cellular signaling processes .
Where is ETNK2 expressed in normal human tissues?
ETNK2 shows tissue-specific expression patterns, being predominantly expressed in kidney, liver, testis, ovary, and prostate tissues . Studies have shown that ETNK2 is upregulated during testis development, suggesting a potential role in reproductive biology . Researchers investigating ETNK2 expression should consider using tissue-specific controls and quantitative PCR or immunohistochemistry methods to accurately characterize expression levels across different tissues.
What genomic and structural information is available for ETNK2?
ETNK2 is located on chromosome 1q32.1 and consists of 11 exons . The gene can undergo alternative splicing, resulting in multiple transcript variants . For researchers studying ETNK2, it's important to note which specific isoform is being investigated, as functional differences may exist between variants. Current genomic databases provide comprehensive information including sequence variations through resources like ClinVar, dbVar, and SNP databases .
How does ETNK2 expression differ in papillary thyroid carcinoma compared to normal tissue?
ETNK2 is significantly upregulated in papillary thyroid carcinoma (PTC) compared to non-neoplastic thyroid tissue, as demonstrated by both TCGA database analysis and RT-qPCR validation in patient samples . Research methodologies for studying this differential expression should include both bioinformatic analysis of public datasets and experimental validation using paired tumor/normal tissue samples. Statistical analysis should account for patient variables such as age, sex, and disease stage .
What clinical characteristics correlate with ETNK2 expression in PTC?
High ETNK2 expression in PTC has been significantly associated with histological type (P<0.001), lymph node metastasis (P<0.001), and disease stage (P=0.011) . Multivariate logistic regression analysis has shown that ETNK2 expression (OR=1.536, CI: 1.014-2.329, p=0.043) is independently associated with lymph node metastasis . Researchers should conduct comprehensive clinicopathological analysis with sufficient sample sizes to detect these correlations, and consider multivariate models to control for confounding factors.
What are effective methods for silencing ETNK2 expression in experimental models?
RNA interference using siRNA has been successfully employed to silence ETNK2 expression in PTC cell lines . Commercial siRNAs targeting ETNK2 are available, such as sc-78755 from Santa Cruz Biotechnology . When designing knockdown experiments, researchers should include appropriate controls (si-NC), validate knockdown efficiency using both mRNA (RT-qPCR) and protein (Western blot) assays, and assess multiple functional outcomes (proliferation, migration, invasion, apoptosis, and cell cycle) to comprehensively characterize the effects of ETNK2 silencing .
What functional assays are most informative for studying ETNK2's biological effects?
Based on published studies, several functional assays have proven informative for characterizing ETNK2's biological effects:
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Cell proliferation: CCK-8 assay and colony formation assays
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Cell migration and invasion: Transwell assays
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Apoptosis: Flow cytometry with appropriate staining (e.g., Annexin V/PI)
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Cell cycle analysis: Flow cytometry with PI staining
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Protein expression and pathway analysis: Western blotting for key pathway components (HIPPO pathway: YAP, TAZ; EMT markers)
These assays should be performed with appropriate technical and biological replicates to ensure reproducibility of results.
Through which signaling pathways does ETNK2 influence cancer progression?
Evidence suggests that ETNK2 may promote cancer progression through the HIPPO and epithelial-mesenchymal transition (EMT) pathways . In PTC cell lines, knockdown of ETNK2 decreased expression levels of YAP, TAZ, and NCA, while increasing expression of ECA . The HIPPO pathway is a key regulator of organ size control and tissue homeostasis, with important implications in cancer development. Advanced researchers should investigate the direct molecular interactions between ETNK2 and these pathway components using techniques like co-immunoprecipitation, proximity ligation assays, or CRISPR-based genetic screens.
How does ETNK2 influence the tumor microenvironment and immune cell infiltration?
Research in KIRC has linked ETNK2 expression to immune cell infiltration patterns . The immunosuppressive tumor microenvironment associated with low ETNK2 expression may contribute to poorer outcomes in KIRC patients. Methodologically, researchers can use computational deconvolution methods on bulk RNA-seq data or single-cell RNA-seq approaches to characterize immune cell populations in relation to ETNK2 expression. Validation should include spatial transcriptomics or multiplexed immunohistochemistry to confirm computational findings.
What explains the contradictory roles of ETNK2 in different cancer types?
The contrasting roles of ETNK2 in PTC (upregulated, oncogenic) versus KIRC (downregulated, associated with poor prognosis) present an intriguing research question. This tissue-specific function might be explained by:
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Differences in baseline phospholipid metabolism between tissues
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Tissue-specific interaction partners of ETNK2
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Variations in dominant signaling pathways across cancer types
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Epigenetic regulation differences
To investigate these possibilities, researchers should conduct comparative multi-omics studies across cancer types, including transcriptomics, proteomics, and metabolomics approaches focused on phospholipid metabolism pathways.
How might ETNK2's enzymatic function relate to its effects on cell proliferation and migration?
As an ethanolamine kinase, ETNK2's primary function is phosphorylating ethanolamine in phospholipid biosynthesis. The connection between this enzymatic activity and its effects on cancer cell behavior requires further investigation. Methodologically, researchers should:
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Create enzymatically inactive mutants to determine if kinase activity is required for oncogenic effects
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Perform metabolomic profiling to identify changes in phospholipid composition after ETNK2 manipulation
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Investigate membrane properties and lipid raft organization in relation to ETNK2 expression
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Examine how phospholipid changes might affect receptor localization and signaling
What is the potential of ETNK2 as a therapeutic target or biomarker?
Based on its differential expression and correlation with clinical outcomes, ETNK2 shows potential as both a biomarker and therapeutic target. For biomarker development, researchers should:
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Conduct large-scale validation studies with diverse patient cohorts
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Develop standardized assays for clinical implementation
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Evaluate ETNK2 in combination with other established biomarkers
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Assess its performance in liquid biopsies
For therapeutic development, researchers should:
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Screen for specific inhibitors of ETNK2's enzymatic activity
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Evaluate the effects of ETNK2 inhibition in various preclinical models
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Investigate potential synergies with standard-of-care treatments
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Assess potential toxicities given ETNK2's expression in normal tissues
What are the epigenetic mechanisms regulating ETNK2 expression?
Understanding the regulatory mechanisms controlling ETNK2 expression could provide insights into its dysregulation in cancer. Researchers should investigate:
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Promoter methylation status across cancer types
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Histone modifications at the ETNK2 locus
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Transcription factor binding profiles
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microRNA-mediated regulation
Methods should include bisulfite sequencing, ChIP-seq, and reporter assays to characterize the regulatory landscape of ETNK2.
How does ETNK2 function in non-cancer pathologies?
While cancer-related functions of ETNK2 have been investigated, its role in other pathologies remains largely unexplored. Given its expression in kidney and liver, researchers might investigate its involvement in:
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Metabolic disorders
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Kidney diseases
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Liver pathologies
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Reproductive disorders
Approaches could include targeted gene knockout in tissue-specific mouse models, analysis of human disease cohorts, and integration with GWAS data that has linked ETNK2 to conditions like chronic periodontitis .
Product Science Overview
Ethanolamine Kinase 2 is encoded by the ETNK2 gene in humans. The enzyme is responsible for phosphorylating ethanolamine to form phosphoethanolamine, which is a precursor in the biosynthesis of phosphatidylethanolamine. Phosphatidylethanolamine is a major phospholipid found in biological membranes and is essential for maintaining membrane integrity and function .
Recombinant human ETNK2 can be produced using various expression systems. One common method involves the use of Escherichia coli (E. coli) as the host organism. The ETNK2 gene is cloned into an expression vector, which is then introduced into E. coli cells. The recombinant protein is expressed with an N-terminal His-tag, which facilitates its purification using affinity chromatography .
Another method involves the use of a wheat germ expression system. In this approach, the ETNK2 gene is cloned into a vector and expressed in vitro using wheat germ extract. The recombinant protein is then purified using standard protein purification techniques .
Ethanolamine Kinase 2 catalyzes the phosphorylation of ethanolamine to form phosphoethanolamine. This reaction is the first step in the CDP-ethanolamine pathway, which ultimately leads to the synthesis of phosphatidylethanolamine. The enzyme’s activity can be analyzed using various biochemical assays that measure the formation of phosphoethanolamine from ethanolamine .
The recombinant ETNK2 protein is often used in research to study its role in phospholipid biosynthesis and its potential implications in various diseases. It is important to note that the recombinant protein may not always retain its full enzymatic activity, and its functionality should be verified through appropriate assays .
