Details for: CL0000066

Cell ID: CL0000066

Cell Name: epithelial cell

Description: A cell that is usually found in a two-dimensional sheet with a free surface. The cell has a cytoskeleton that allows for tight cell to cell contact and for cell polarity where apical part is directed towards the lumen and the basal part to the basal lamina.

Synonyms: epitheliocyte

Selected Context(s): Overall

Gene Significance Landscape

Display Options
Score:
Display
Genes

Contexts:

Cell Significance Index (CSI) is uniquely calculated to reveal cell-specific gene markers. More info here

Image representation

Depiction of epithelial cell
Courtesy of SwissBioPics

Significant Genes List

Genes with the highest and lowest Percentile Rank Scores (PRS) for epithelial cell within the selected context(s).

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for epithelial cell. Higher scores indicate a stronger, more significant difference in expression.
(Previously described as "Fold Change", but now represents Cliff's Delta × –log10(p).)

Gene ID: A unique numerical identifier for this specific gene.
Symbol: Shortened abbreviation or name that represents this gene.
Ensembl Gene ID: A unique identifier assigned by Ensembl for genomic data mapping.
CSI Score: A combined effect size and statistical significance measure for epithelial cell. Higher scores indicate a stronger, more significant difference in expression.
Average CSI: csi sum / gene count
Cell network configuration

This network visualizes key genes for epithelial cell. It primarily includes:
1. Top genes highly significant for this cell (Num. Top Cell Genes - based on the 'Min. CSI' setting).
2. Any additional specific 'Context Genes' you add below.
The final network is a combined view. Choose an Interaction Source (pathways or protein interactions) and optionally compare CSI scores with a Baseline Cell Type.

Maximum number of selected genes.
Select a context for the baseline cell.
Select a context for the target cell.
Target Cell for CSI:  epithelial cell (CL0000066)

 Legend
Nodes (Genes):
 Query Gene
Node size also reflects Target Cell CSI magnitude.
Node Color (Target Cell CSI in specific network):
 Very High
 High
 Medium
 Low
 Very Low
 N/A or Not Sig.
Edges (Interactions):
 STRING (Protein-Protein)
 ONTOLOGY (Shared Pathway)
 Colors vary by pathway category; default arrow applies.

Loading network (please wait)...

## Summary The [epithelial cell](/details-cell/CL0000066), or epitheliocyte, is a fundamental cell type that forms cohesive sheets, establishing barriers and specialized surfaces within an organism. As defined by its formal description, it is characterized by a distinct apical-basal polarity and tight cell-to-cell contacts. The gene significance profile underscores this role, revealing that beyond its structural function, the [epithelial cell](/details-cell/CL0000066) is a hub of intense metabolic activity and protein synthesis. The high specificity score ([csi_z](/glossary/csi_z): 70.13) for [TPT1](/details-gene/7178), a translationally controlled tumor protein, suggests that tightly regulated protein production is a defining characteristic of this lineage, essential for maintaining its structural integrity, secretory functions, and barrier homeostasis. ## Key Characteristics and Function **Overall**, the gene expression landscape of the [epithelial cell](/details-cell/CL0000066) points to a cell type with exceptionally high energetic demands, robust protein turnover, and crucial homeostatic functions. The top markers can be grouped into several key functional clusters: * **High Metabolic Activity:** A significant number of top markers are components of the mitochondrial respiratory chain, highlighting a reliance on aerobic respiration. These include multiple subunits of cytochrome c oxidase ([COX4I1](/details-gene/1327), [COX1](/details-gene/4512), [COX7C](/details-gene/1350), [COX5B](/details-gene/1329)) and NADH dehydrogenase ([ND2](/details-gene/4536), [ND4](/details-gene/4538)), as well as a subunit of ATP synthase ([ATP5F1E](/details-gene/514)). The high specificity of these genes suggests that this intense energy production is not merely a housekeeping function but a specialized feature required for active transport, secretion, and maintenance of the epithelial barrier. * **Protein Synthesis and Regulation:** The cell is defined by a powerful protein synthesis and quality control apparatus. [TPT1](/details-gene/7178) and [EEF1B2](/details-gene/1933) are directly involved in translation, while [PABPC1](/details-gene/26986) and [SRP14](/details-gene/6727) are critical for RNA binding and protein targeting. The ubiquitin gene [UBC](/details-gene/7316) further points to a highly active system for protein degradation and turnover, essential for cellular homeostasis and rapid adaptation. * **Cytoskeletal Dynamics and Structural Integrity:** Genes such as [MYL6](/details-gene/4637) (myosin light chain) and [CFL1](/details-gene/1072) (cofilin) are key regulators of the cytoskeleton. Their prominence indicates that maintaining cell shape, polarity, and the integrity of cell-cell junctions is a continuous and dynamic process fundamental to epithelial function. * **Cellular Homeostasis and Defense:** [Epithelial cells](/details-cell/CL0000066) are clearly equipped to manage metabolic byproducts and environmental stress. The high significance of ferritin heavy and light chains ([FTH1](/details-gene/2495) and [FTL](/details-gene/2512)) points to a critical role in iron sequestration, likely to prevent oxidative damage from Fenton reactions. This is complemented by [GSTP1](/details-gene/2950), a glutathione S-transferase involved in detoxification and response to reactive oxygen species, a vital function for a barrier cell type. Furthermore, the presence of [B2M](/details-gene/567) as a marker indicates their role in antigen presentation via MHC class I, positioning them as an integral part of the immune surveillance system. The **Anti_Markers** profile helps refine this identity. The low significance of genes associated with highly specialized differentiation, such as [SPRR2D](/details-gene/6703) (cornified envelope precursor), suggests the analysis captures a general epithelial signature, distinct from terminally differentiated keratinocytes. Similarly, the low ranking of developmental signaling modulators like [DKK1](/details-gene/22943) may indicate that constitutive Wnt signaling is a common feature for epithelial maintenance across various tissues. ## Clinical Significance and Contextual Roles The **Overall** gene signature portrays the [epithelial cell](/details-cell/CL0000066) as a cornerstone of tissue health, whose dysfunction is central to a wide array of pathologies. The high expression of metabolic machinery ([COX1](/details-gene/4512), [ATP5F1E](/details-gene/514)) makes these cells vulnerable to mitochondrial dysfunction, a factor implicated in aging and degenerative diseases. The prominence of [GSTP1](/details-gene/2950) is clinically relevant, as its overexpression is a known mechanism of chemotherapy resistance in epithelial-derived cancers. This suggests that the innate detoxification capacity of healthy [epithelial cells](/details-cell/CL0000066) can be co-opted during malignant transformation. The top marker, [TPT1](/details-gene/7178), is widely studied for its role in cell growth and its high expression in various tumors, indicating that the regulatory pathways governing its function are critical for controlling epithelial proliferation and can be hijacked in cancer. Furthermore, the expression of [B2M](/details-gene/567) highlights the constant dialogue between [epithelial cells](/details-cell/CL0000066) and the immune system. Loss or downregulation of [B2M](/details-gene/567) is a known immune escape mechanism for tumors and virally infected cells, allowing them to evade cytotoxic T cell recognition. Thus, the baseline expression level of [B2M](/details-gene/567) is a key determinant of immune surveillance at epithelial surfaces. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The specific, coordinated co-expression of mitochondrial respiratory components and translational machinery is an adaptive program fundamental to epithelial identity. This program likely couples cellular energy status directly to the synthesis of proteins essential for barrier function, polarity, and specialized secretions, ensuring that structural integrity is maintained under high metabolic demand. * **Surprising Findings:** It is striking that a "translationally controlled tumor protein," [TPT1](/details-gene/7178), is the single most specific marker for this general cell type. This suggests that the molecular mechanisms controlling its expression are not exclusive to pathology but are central to normal epithelial homeostasis, possibly acting as a master regulator of the epithelial proteome in response to metabolic cues. * **Testable Questions:** Does pharmacologic inhibition of mitochondrial ATP production via drugs targeting cytochrome c oxidase disproportionately reduce the translation of key structural proteins (e.g., keratins, E-cadherin) compared to other housekeeping proteins in epithelial cell monolayers? 2. **Hypothesis:** The constitutive high-level expression of iron-sequestering proteins ([FTH1](/details-gene/2495), [FTL](/details-gene/2512]) and detoxification enzymes ([GSTP1](/details-gene/2950]) represents a primary, preemptive defense system in [epithelial cells](/details-cell/CL0000066). This system is critical for mitigating oxidative stress generated by both high mitochondrial activity and external environmental insults, thereby protecting genomic and cellular integrity at barrier surfaces. * **Surprising Findings:** The fact that iron management genes rank among the most defining markers of the [epithelial cell](/details-cell/CL0000066), surpassing many classical structural markers, elevates their function from general housekeeping to a core, lineage-defining characteristic. This implies that managing iron toxicity is as fundamental to being an epithelial cell as forming a cohesive sheet. * **Testable Questions:** Does siRNA-mediated knockdown of [FTH1](/details-gene/2495) in an epithelial cell culture model lead to increased DNA damage and lipid peroxidation, and does it compromise the integrity of tight junctions when the cells are exposed to sub-lethal doses of pro-oxidants?