Details for: CL0000192

Cell ID: CL0000192

Cell Name: smooth muscle cell

Description: A non-striated, elongated, spindle-shaped cell found lining the digestive tract, uterus, and blood vessels. They develop from specialized myoblasts (smooth muscle myoblast).

Synonyms: non-striated muscle cell, smooth muscle fiber, SMCs, myocytes, smooth muscle

Selected Context(s): Overall

Gene Significance Landscape

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Score:
Display
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 smooth muscle 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 smooth muscle 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 smooth muscle 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 smooth muscle 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:  smooth muscle cell (CL0000192)

 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 [smooth muscle cell](/details-cell/CL0000192) is a non-striated, spindle-shaped cell type fundamental to the contractile function of hollow organs such as blood vessels, the digestive tract, and the uterus. **Overall**, the gene significance profile suggests that beyond its canonical role in contraction, this cell is characterized by a remarkably high metabolic activity, robust protein synthesis and quality control machinery, and specific ion management systems. The top-ranking marker, [B2M](/details-gene/567) (`csi_z`: 41.64), which encodes Beta-2-microglobulin, points to a potentially significant role in protein folding and antigen presentation, an aspect not traditionally emphasized in its mechanical function. This is complemented by strong markers for the contractile apparatus, such as [MYL6](/details-gene/4637), and a suite of genes involved in energy production and calcium signaling, painting a picture of a cell that is both a structural workhorse and a dynamic metabolic hub. ## Key Characteristics and Function Analysis of top marker genes, ranked by expression specificity (`csi_z`), reveals several core functional clusters that define the [smooth muscle cell](/details-cell/CL0000192). * **Contractile and Cytoskeletal Machinery:** A prominent group of markers is directly involved in the cell's primary contractile function, which is heavily reliant on calcium signaling. This includes [MYL6](/details-gene/4637), a myosin alkali light chain essential for microfilament motor activity ([Link](https://doi.org/10.1016/s0021-9258(18)81895-6)), and several calcium-binding proteins like [S100A6](/details-gene/6277) and [CALM2](/details-gene/805) (Calmodulin). The significance of [KCNIP4](/details-gene/80333), a potassium channel interacting protein, and microtubule-associated protein [MAP1B](/details-gene/4131) further underscores the sophisticated regulation of ion flux and cytoskeletal organization required for sustained tonic contractions. * **High Metabolic Demand:** The data strongly suggest that [smooth muscle cells](/details-cell/CL0000192) have a high and constant energy requirement. This is evidenced by the specific expression of numerous mitochondrial genes involved in aerobic respiration. Key markers include [NDUFA4](/details-gene/4697), [COX7C](/details-gene/1350), [COX1](/details-gene/4512), and [ND4](/details-gene/4538), all components of the electron transport chain. The high significance of [SLC25A6](/details-gene/293), an ADP/ATP translocase that shuttles energy out of the mitochondria, further supports the notion of this cell as a major energy consumer. * **Protein Synthesis and Homeostasis:** The top marker, [B2M](/details-gene/567), is an essential component of MHC class I molecules, pointing towards active protein folding and presentation pathways. This theme is reinforced by the presence of [UBC](/details-gene/7316) (Polyubiquitin-C), a critical element of the protein degradation machinery, and [SRP14](/details-gene/6727), a component of the signal recognition particle that directs proteins for secretion or membrane insertion. Furthermore, high specificity for ferritin heavy and light chains, [FTH1](/details-gene/2495) and [FTL](/details-gene/2512) respectively, highlights a specialized role in iron sequestration. Iron is a critical cofactor for mitochondrial enzymes, linking this function directly to the cell's metabolic activity. * **RNA Processing and Regulation:** The profile includes genes involved in post-transcriptional regulation, such as the long non-coding RNA [NEAT1](/details-gene/283131), known for its role in nuclear paraspeckle formation and gene silencing, and [PABPC1](/details-gene/26986), a poly(A)-binding protein crucial for mRNA stability and translation. This suggests that gene expression in [smooth muscle cells](/details-cell/CL0000192) is tightly regulated at multiple post-transcriptional levels. The anti-marker profile helps to refine the cell's identity. The low significance of developmental regulators like [BMP4](/details-gene/652) and [SOSTDC1](/details-gene/25928), as well as transcription factors such as [MYOCD](/details-gene/93649) (Myocardin), is consistent with a mature, differentiated cellular state rather than one undergoing active specification. The absence of hematopoietic markers like [HBG1](/details-gene/3047) (Hemoglobin Subunit Gamma 1) correctly distinguishes it from blood cell lineages. ## Clinical Significance and Contextual Roles The gene signature of the [smooth muscle cell](/details-cell/CL0000192) provides insights into its potential roles in various pathologies. The pronounced metabolic profile, characterized by high expression of mitochondrial components like [COX1](/details-gene/4512) and [ND4](/details-gene/4538), suggests that metabolic dysregulation could be a central mechanism in vascular diseases. In conditions like atherosclerosis or hypertension, altered mitochondrial function in vascular [smooth muscle cells](/details-cell/CL0000192) could lead to oxidative stress, proliferation, and impaired contractility. Dysregulation of the contractile and calcium-signaling machinery, underscored by markers like [MYL6](/details-gene/4637) and [CALM2](/details-gene/805), is directly implicated in diseases of abnormal smooth muscle tone. For example, hyperactivity of these pathways contributes to bronchoconstriction in asthma and elevated vascular resistance in hypertension. The high ranking of [B2M](/details-gene/567) is particularly intriguing from a clinical perspective. While essential for immune surveillance, its prominence here may suggest that [smooth muscle cells](/details-cell/CL0000192) are more immunologically active than previously appreciated. In the context of atherosclerosis, the presentation of endogenous or modified-lipid antigens by vascular [smooth muscle cells](/details-cell/CL0000192) could contribute to the chronic inflammation that drives plaque formation. Similarly, the high specificity of genes involved in iron handling ([FTL](/details-gene/2512), [FTH1](/details-gene/2495)) points to a potential vulnerability, as iron overload can catalyze the formation of reactive oxygen species, a known contributor to cardiovascular disease. ## Potential Mechanisms and Research Directions 1. **Hypothesis: Iron homeostasis, mediated by ferritin, is a critical upstream regulator of mitochondrial function and contractile endurance in [smooth muscle cells](/details-cell/CL0000192).** * **Surprising Findings:** The high expression specificity of both ferritin subunits, [FTL](/details-gene/2512) and [FTH1](/details-gene/2495), is not a canonical feature of smooth muscle identity but appears to be a defining characteristic in this dataset. This suggests their role in managing iron as a cofactor for mitochondrial cytochromes may be as important as the respiratory chain components themselves. * **Testable Questions:** Does targeted knockdown of [FTL](/details-gene/2512) or [FTH1](/details-gene/2495) in vascular [smooth muscle cells](/details-cell/CL0000192) lead to measurable defects in mitochondrial respiration and a reduced capacity to sustain vasoconstriction under metabolic stress? 2. **Hypothesis: The MHC class I pathway in [smooth muscle cells](/details-cell/CL0000192), highlighted by the top marker [B2M](/details-gene/567), serves a dual role in both classical immune surveillance and as a quality control mechanism for clearing damaged or misfolded contractile proteins.** * **Surprising Findings:** It is unexpected for [B2M](/details-gene/567), a core component of the antigen presentation machinery, to exhibit greater expression specificity than classical contractile proteins like [MYL6](/details-gene/4637). This suggests its function may extend beyond immunology. * **Testable Questions:** In cultured [smooth muscle cells](/details-cell/CL0000192) subjected to oxidative stress, do peptides derived from contractile proteins (e.g., actin, myosin) become enriched in the pool of MHC class I-presented antigens on the cell surface?