Details for: CL0000162

Cell ID: CL0000162

Cell Name: parietal cell

Description: An epithelial cell of the stomach that is part of the fundic gastric gland. This cell is characterized by its pyramidal shape, abundant mitochondria, and a complex network of secretory canaliculi lined with microvilli. It secretes hydrochloric acid into the stomach lumen and produces intrinsic factor, essential for vitamin B12 absorption.

Synonyms: gastric parietal cell, oxyntic cell

Selected Context(s): Overall

Gene Significance Landscape

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Score:
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Genes

Contexts:

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

Significant Genes List

Genes with the highest and lowest Percentile Rank Scores (PRS) for parietal 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 parietal 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 parietal 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 parietal 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:  parietal cell (CL0000162)

 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.

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## Summary The [parietal cell](/details-cell/CL0000162), also known as an oxyntic cell, is a specialized epithelial cell within the stomach's fundic glands, primarily responsible for secreting hydrochloric acid and intrinsic factor. The gene significance profile underscores this cell's identity as a metabolic powerhouse. An overwhelming majority of its top-scoring markers, as defined by expression specificity (`csi_z`), are components of the mitochondrial respiratory chain and ATP synthesis machinery. This genetic signature is highly consistent with the immense energy demand required for pumping ions across a steep electrochemical gradient to produce gastric acid. ## Key Characteristics and Function **Overall**, the molecular identity of the [parietal cell](/details-cell/CL0000162) is dominated by genes essential for aerobic respiration and energy production. This reflects its primary physiological role, which is one of the most energy-intensive processes in the body. * **Mitochondrial Bioenergetics:** A remarkable number of the top markers are subunits of the mitochondrial electron transport chain and ATP synthase complexes. This includes multiple cytochrome c oxidase subunits ([COX4I1](/details-gene/1327), [COX5B](/details-gene/1329), [COX6C](/details-gene/1345), [COX7C](/details-gene/1350), [COX7A2](/details-gene/1347)), NADH:ubiquinone oxidoreductase subunit [NDUFA4](/details-gene/4697), ubiquinol-cytochrome c reductase binding protein [UQCRB](/details-gene/7381), and several ATP synthase subunits ([ATP5F1E](/details-gene/514), [ATP5MG](/details-gene/10632), [ATP5F1B](/details-gene/506), [ATP5PF](/details-gene/522), [ATP5ME](/details-gene/521)). The high specificity scores (`csi_z`) for these genes suggest that their expression levels are uniquely elevated in parietal cells compared to other cell types, establishing this intense metabolic capacity as a defining feature of the cell's identity. The ATP/ADP translocase [SLC25A6](/details-gene/293) further supports this by highlighting the machinery needed to transport the vast amounts of ATP out of the mitochondria. * **Metabolic Support and Iron Homeostasis:** Beyond direct energy production, key metabolic enzymes like lactate dehydrogenase B ([LDHB](/details-gene/3945)) and glyceraldehyde-3-phosphate dehydrogenase ([GAPDH](/details-gene/2597)) are significant markers. The prominence of ferritin light and heavy chains ([FTL](/details-gene/2512) and [FTH1](/details-gene/2495)) suggests a specialized role in iron storage and management. This is likely critical for synthesizing the iron-containing heme groups required by the numerous cytochrome proteins of the respiratory chain. * **Protein Synthesis and Immune Components:** The high score for Beta-2-microglobulin ([B2M](/details-gene/567)) is noteworthy. While classically associated with MHC class I antigen presentation in immune cells, its strong specificity in this epithelial cell may point towards high protein turnover or a non-canonical role. Similarly, the signal recognition particle subunit [SRP14](/details-gene/6727) indicates a robust capacity for co-translational protein translocation, essential for a secretory cell. The anti-marker profile helps refine the cell's functional specialization. The low significance of genes involved in RNA processing ([HNRNPC](/details-gene/3183), [SRSF5](/details-gene/6430)) and nuclear structure ([SON](/details-gene/6651)) does not imply these functions are absent, but rather that they are not the uniquely defining activities of the cell compared to its massive investment in mitochondrial bioenergetics. ## Clinical Significance and Contextual Roles The gene profile provides a snapshot of the [parietal cell](/details-cell/CL0000162) in a general, or **Overall**, context. The profound and specific reliance on oxidative phosphorylation implies a unique vulnerability to mitochondrial dysfunction. Pathologies affecting the electron transport chain or ATP synthesis would likely manifest with severe gastric symptoms due to impaired acid secretion (achlorhydria) and potential parietal cell death. This could lead to malabsorption of vitamin B12, causing pernicious anemia, as the cell also produces intrinsic factor. Furthermore, the high expression of ferritin ([FTL](/details-gene/2512), [FTH1](/details-gene/2495)) suggests that disorders of iron metabolism could specifically impact parietal cell function by limiting the availability of essential cofactors for the cytochrome proteins. The data highlights this cell type as a potential key player in the gastrointestinal manifestations of systemic mitochondrial diseases. The specific marker [B2M](/details-gene/567) is also linked to dialysis-related amyloidosis, and its unique expression level here might warrant investigation into specific gastric roles or vulnerabilities. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The extreme enrichment of mitochondrial respiratory chain gene expression in parietal cells is not merely a passive response to energy demand but is driven by a distinct, constitutively active transcriptional program. This program ensures the continuous biogenesis and maintenance of a vast mitochondrial network, making it a central pillar of the cell's identity. * **Surprising Findings:** The high specificity score for [B2M](/details-gene/567), a component of the MHC Class I complex, is unexpected in a gastric epithelial cell. This suggests a potential non-canonical, non-immune function in this high-energy context, or a unique interaction with the gastric immune environment. * **Testable Questions:** Can single-cell ATAC-seq identify a unique set of open chromatin regions and transcription factor binding motifs upstream of mitochondrial biogenesis genes ([NDUFA4](/details-gene/4697), [COX4I1](/details-gene/1327), etc.) that are specific to parietal cells compared to neighboring chief or mucous neck cells? 2. **Hypothesis:** The specific, high-level expression of ferritin subunits ([FTL](/details-gene/2512) and [FTH1](/details-gene/2495)) indicates that parietal cells possess a specialized iron-buffering system that is critical for supplying iron cofactors to the abundant heme-containing cytochrome proteins. This system may function as a rate-limiting checkpoint for maintaining the cell's formidable respiratory capacity. * **Surprising Findings:** It is notable that a canonical "housekeeping" gene like [GAPDH](/details-gene/2597) ranks as a highly specific marker. This suggests either that glycolysis is exceptionally active to fuel the TCA cycle or that the known non-glycolytic functions of GAPDH are particularly pronounced and specialized in parietal cells. * **Testable Questions:** Does targeted silencing of [FTH1](/details-gene/2495) in a gastric organoid model lead to a measurable decrease in cytochrome c oxidase activity and a subsequent reduction in proton pump function, even in iron-replete culture conditions?