Details for: CL0000556

Cell ID: CL0000556

Cell Name: megakaryocyte

Description: Megakaryocytes are reportedly CD181-positive and CD182-positive.

Synonyms: megacaryocyte, megalocaryocyte, megalokaryocyte

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

Significant Genes List

Genes with the highest and lowest Percentile Rank Scores (PRS) for megakaryocyte 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 megakaryocyte. 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 megakaryocyte. 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 megakaryocyte. 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:  megakaryocyte (CL0000556)

 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 [megakaryocyte](/details-cell/CL0000556) is a highly specialized, large bone marrow cell primarily responsible for the production of platelets, which are essential for hemostasis. The gene significance profile underscores this function, revealing a cell with an exceptionally active biosynthetic and metabolic machinery. High expression specificity of genes involved in cytoskeletal organization, protein synthesis, and energy production defines its role as a platelet factory. Notably, the top marker, [B2M](/details-gene/567), a component of MHC Class I molecules, suggests that beyond its hemostatic role, the [megakaryocyte](/details-cell/CL0000556) may also possess significant immunomodulatory functions within its microenvironment. ## Key Characteristics and Function The gene expression landscape of the [megakaryocyte](/details-cell/CL0000556) is dominated by several key functional clusters that collectively enable its primary role in thrombopoiesis. * **Cytoskeletal Dynamics and Proplatelet Formation:** A suite of highly significant genes points to a sophisticated and dynamic cytoskeleton, which is a prerequisite for the formation of proplatelet extensions. These include [CFL1](/details-gene/1072) (cofilin 1), an actin-depolymerizing factor crucial for cytoskeletal remodeling, and multiple myosin light chains ([MYL12A](/details-gene/10627), [MYL12B](/details-gene/103910), [MYL6](/details-gene/4637)) that regulate actomyosin contractility. These proteins are fundamental to the dramatic changes in cell shape required for extending and releasing thousands of platelets into the circulation, a process consistent with their annotation in pathways such as 'Platelet degranulation' and 'Hemostasis'. * **High Bioenergetic Output:** The cell's immense biosynthetic demands are supported by a powerful metabolic engine. This is evidenced by the high significance of multiple genes encoding subunits of the mitochondrial ATP synthase complex ([ATP5F1E](/details-gene/514), [ATP5MG](/details-gene/10632)) and cytochrome c oxidase ([COX4I1](/details-gene/1327)), as well as the core glycolytic enzyme [GAPDH](/details-gene/2597). This indicates a high capacity for aerobic respiration to fuel the synthesis of proteins and lipids required for platelet formation. * **Intensive Protein Synthesis and Processing:** The profile is characteristic of a protein synthesis factory, with high specificity for genes like the translation elongation factor [EEF1B2](/details-gene/1933), the poly(A)-binding protein [PABPC1](/details-gene/26986) which regulates mRNA stability and translation, and components of the protein translocation and modification machinery such as [SRP14](/details-gene/6727) and [OST4](/details-gene/100128731). This robust system is necessary to produce the vast array of proteins packaged into nascent platelets. * **Nuclear Organization and Regulation:** The high significance of the replacement histone variants [H3.3A](/details-gene/3020) and [H3.3B](/details-gene/3021) suggests a dynamic chromatin state adapted for a terminally differentiated, polyploid cell that is metabolically active but no longer dividing. Furthermore, the prominence of [OAZ1](/details-gene/4946), an inhibitor of polyamine synthesis, points towards tight regulation of cellular growth processes. * **Immunomodulatory and Signaling Roles:** The single most specific marker identified is [B2M](/details-gene/567), the light chain of MHC Class I molecules. Its exceptional CSI score suggests a role in antigen presentation that may be more significant than previously appreciated. This is complemented by the high significance of [HMGB1](/details-gene/3146), a nuclear protein that can act as a damage-associated molecular pattern (DAMP) upon release, and [TREML1](/details-gene/340205), a putative inhibitory receptor found on myeloid-lineage cells, hinting at a capacity to both present antigens and regulate local immune responses. ## Clinical Significance and Contextual Roles **Overall**, the gene profile of [megakaryocytes](/details-cell/CL0000556) highlights their central role in both hemostasis and, potentially, immunology. The machinery for platelet production is clearly defined, and disruptions in the function of key cytoskeletal genes like [CFL1](/details-gene/1072) or the myosin light chains could theoretically lead to either thrombocytopenia (low platelet count) or thrombocytosis (high platelet count). The prominent immunomodulatory signature, particularly the high specificity of [B2M](/details-gene/567), could have clinical implications. Altered antigen presentation by [megakaryocytes](/details-cell/CL0000556) might contribute to autoimmune disorders or influence the bone marrow's response to infection or malignancy. For instance, in hematological cancers, the ability of malignant [megakaryocytes](/details-cell/CL0000556) to interact with immune cells via MHC-I could impact immune evasion. Additionally, the high significance of [HMGB1](/details-gene/3146) suggests that megakaryocyte stress or death could be a source of this potent pro-inflammatory mediator, potentially linking hematopoiesis to systemic inflammatory conditions. The unique metabolic profile, marked by high expression of specific mitochondrial subunits like [ATP5F1E](/details-gene/514) and [COX4I1](/details-gene/1327), may represent a vulnerability. Pathologies that impair mitochondrial function could disproportionately affect thrombopoiesis, highlighting a potential link between mitochondrial diseases and bleeding or clotting disorders. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The striking prominence of [B2M](/details-gene/567) and other immune-related genes such as [HMGB1](/details-gene/3146) and [TREML1](/details-gene/340205) suggests that [megakaryocytes](/details-cell/CL0000556) function as integral components of the bone marrow immune niche, actively engaging in antigen presentation and modulating inflammatory signaling. * **Surprising Findings:** The top-ranked gene by expression specificity is an MHC Class I component, superseding canonical platelet-related structural genes. The high specificity of [NRGN](/details-gene/4900), a calmodulin-binding protein typically associated with neurons, is also unexpected and may point to specialized calcium-dependent signaling cascades that integrate immune signaling with platelet production. * **Testable Questions:** How does the antigen repertoire presented by [megakaryocytes](/details-cell/CL0000556) on their MHC-I molecules influence the activity of resident bone marrow T cells ([T-cell](/details-cell/CL0000084))? Could platelets released into circulation carry an antigenic "memory" from the bone marrow microenvironment, thereby influencing peripheral immune surveillance? 2. **Hypothesis:** The distinct combination of highly significant replacement histones ([H3.3A](/details-gene/3020), [H3.3B](/details-gene/3021)) and specific mitochondrial respiratory chain subunits (e.g., [ATP5F1E](/details-gene/514), [COX4I1](/details-gene/1327)) indicates that [megakaryocytes](/details-cell/CL0000556) adopt a unique and highly optimized cellular state to sustain extreme bioenergetic demands for thrombopoiesis while remaining in a terminally differentiated, non-proliferative state. * **Surprising Findings:** While many mitochondrial genes are highly significant, several core mitochondrial-encoded genes such as [COX3](/details-gene/4514) and [ATP6](/details-gene/4508) are not. This discrepancy suggests a specific proteomic configuration of the respiratory chain, perhaps tailored for efficiency or regulation, rather than a general upregulation of all mitochondrial components. * **Testable Questions:** Does the specific isoform composition of the mitochondrial electron transport chain in [megakaryocytes](/details-cell/CL0000556) confer a bioenergetic advantage or a unique regulatory mechanism? Does pharmacologic or genetic inhibition of the top-ranked nuclear-encoded subunit [COX4I1](/details-gene/1327) have a more profound impact on proplatelet formation than inhibition of the mitochondrially-encoded [COX3](/details-gene/4514)?