Details for: CL4030063

Cell ID: CL4030063

Cell Name: L4 intratelencephalic projecting glutamatergic neuron

Description: Historically, the L4 intratelencephalic projectic glutametergic neuron was known to have its soma in cortical layer 4. MERFISH data showed that this intratelencephalic-projecting glutametergic neuron can also have its soma in layer 3.

Synonyms: L4 IT

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 L4 intratelencephalic projecting glutamatergic neuron 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 L4 intratelencephalic projecting glutamatergic neuron. 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 L4 intratelencephalic projecting glutamatergic neuron. 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 L4 intratelencephalic projecting glutamatergic neuron. 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:  L4 intratelencephalic projecting glutamatergic neuron (CL4030063)

 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 L4 intratelencephalic projecting glutamatergic neuron ([L4 intratelencephalic projecting glutamatergic neuron](/details-cell/CL4030063)) is a distinct neuronal cell type found in cortical layers 3 and 4. Based on its gene significance profile, this neuron is characterized by a highly specific and diverse array of neurotransmitter receptors and synaptic proteins. **Overall**, the data strongly suggest that this cell functions as a primary integration center for both excitatory and inhibitory signals within the cortical microcircuit, defined by high expression specificity for key components of glutamate and GABA signaling pathways, such as [GRM5](/details-gene/2915) and various GABA receptor subunits. ## Key Characteristics and Function Analysis of gene significance within the L4 intratelencephalic projecting glutamatergic neuron reveals a molecular identity specialized for complex synaptic communication and plasticity. The top markers can be grouped into several key functional clusters. * **Diverse Neurotransmitter Receptor Expression:** The cell's identity is most prominently defined by its unique repertoire of neurotransmitter receptors. It shows exceptionally high expression specificity for the metabotropic glutamate receptor [GRM5](/details-gene/2915) (CSI: 38.07) and the ionotropic NMDA receptor subunit [GRIN2A](/details-gene/2903) (CSI: 26.39), confirming its glutamatergic nature. Concurrently, it expresses a suite of GABA receptor subunits with high specificity, including the GABA-A receptor subunits [GABRB1](/details-gene/2560) (CSI: 29.86) and [GABRB2](/details-gene/2561) (CSI: 27.04), and the GABA-B receptor subunit [GABBR2](/details-gene/9568) (CSI: 28.21). This diverse receptor profile indicates a sophisticated capacity to receive and process both excitatory and inhibitory inputs across different signaling timescales. * **Synaptic Structure and Vesicle Cycling:** The neuron is enriched in proteins essential for synaptic architecture and function. Key markers include [ERC2](/details-gene/26059) (CSI: 28.74), involved in synaptic vesicle priming, and [SYN2](/details-gene/6854) (CSI: 26.41), a synapsin protein that modulates neurotransmitter release. Additionally, scaffolding proteins like [DLGAP2](/details-gene/9228) (CSI: 25.48) and proteins promoting synapse assembly like [LRRTM3](/details-gene/347731) (CSI: 26.35) are highly specific, underscoring the cell's role in maintaining robust synaptic connections. * **Cell Adhesion and Neuronal Development:** Several top markers are involved in cell adhesion and neurite development, suggesting a role in establishing and maintaining its specific connectivity. [CSMD3](/details-gene/114788) (CSI: 32.75), a large transmembrane protein, and [OPCML](/details-gene/4978) (CSI: 28.36), an opioid-binding cell adhesion molecule, are defining features of this neuron type. Furthermore, the growth factor [NRG3](/details-gene/10718) (CSI: 27.59) is specifically expressed, pointing to its involvement in neural development and cell-cell communication. * **Intracellular Signaling and Transport:** Downstream signaling components are also prominent. The neuron shows specific expression of calcium-dependent signaling molecules such as [CALM1](/details-gene/801) (CSI: 23.92) and [CAMK2A](/details-gene/815) (CSI: 23.16), which are central to synaptic plasticity. The microtubule motor protein [KIF5C](/details-gene/3800) (CSI: 25.32) highlights the importance of active intracellular transport for maintaining neuronal function. * **Anti-Markers:** The least significant genes for this cell type include ubiquitously expressed housekeeping genes involved in fundamental cellular processes. These include components of the mitochondrial electron transport chain ([COX1](/details-gene/4512), [COX2](/details-gene/4513), [COX3](/details-gene/4514)), RNA binding and splicing ([HNRNPC](/details-gene/3183), [FUS](/details-gene/2521)), and protein turnover ([UBC](/details-gene/7316)). The low specificity scores for these genes do not imply their absence but rather indicate that their expression is not a unique or defining characteristic of this neuron compared to other cell types. ## Clinical Significance and Contextual Roles While this analysis is based on an **Overall** context, the specific gene signature of the [L4 intratelencephalic projecting glutamatergic neuron](/details-cell/CL4030063) points to its potential involvement in several neurological and psychiatric disorders. The high specificity of genes encoding GABA receptor subunits, such as [GABRB1](/details-gene/2560), aligns with research implicating GABAergic signaling dysfunction in epilepsy and anxiety disorders. A publication notes a potential link between alternative splicing of [GABRB2](/details-gene/2561) and psychotic disorders ([Link](https://doi.org/10.1371/journal.pone.0006977)). Furthermore, one of the most specific markers, [CSMD3](/details-gene/114788), has been identified as a candidate gene for benign adult familial myoclonic epilepsy ([Link](https://doi.org/10.1016/s0006-291x(03)01555-9)). The specific expression of [NRG3](/details-gene/10718), which activates the ErbB4 receptor, is also noteworthy, as the Neuregulin-ErbB4 pathway has been strongly implicated in the pathophysiology of schizophrenia. Collectively, this molecular profile suggests that dysregulation within L4 IT neurons could disrupt the fine-tuned balance of excitation and inhibition in cortical circuits, potentially contributing to the pathology of epilepsy and certain psychiatric conditions. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The L4 IT neuron acts as a critical computational hub by virtue of its highly specific co-expression of a diverse set of glutamatergic ([GRM5](/details-gene/2915), [GRIN2A](/details-gene/2903)) and GABAergic ([GABRB1](/details-gene/2560), [GABRB2](/details-gene/2561), [GABBR2](/details-gene/9568)) receptors. This molecular machinery allows it to integrate a wide range of synaptic inputs across multiple timescales, and disruptions in the expression or function of these receptors could lead to an excitation/inhibition imbalance underlying neurological disorders like epilepsy. * **Surprising Findings:** It is notable that both metabotropic ([GRM5](/details-gene/2915)) and ionotropic ([GRIN2A](/details-gene/2903)) glutamate receptors, as well as receptors for both fast (GABA-A) and slow (GABA-B) inhibition, are among the most specific markers for a single neuron type. This suggests an intrinsic design for complex signal integration rather than a simple excitatory relay function. * **Testable Questions:** Using patch-clamp electrophysiology in cortical slices, how do selective pharmacological antagonists for GRM5, NMDA, GABA-A, and GABA-B receptors differentially alter the synaptic integration and firing patterns of optogenetically-identified L4 IT neurons? 2. **Hypothesis:** The specific expression of large, multi-domain cell adhesion molecules, particularly [CSMD3](/details-gene/114788), is a primary determinant of the synaptic partnership and circuit assembly of L4 IT neurons during cortical development. Loss-of-function of [CSMD3](/details-gene/114788) may lead to aberrant connectivity and synaptic pruning, contributing to the etiology of neurodevelopmental disorders or epilepsy. * **Surprising Findings:** The second-highest specificity score belongs to [CSMD3](/details-gene/114788), a massive and relatively understudied gene, ranking higher than many canonical synaptic proteins. This suggests its role in defining this neuron's identity and connectivity may be more fundamental than previously appreciated. * **Testable Questions:** Does in vivo knockout of [CSMD3](/details-gene/114788) in L4 IT neurons using viral genetic tools lead to observable changes in their dendritic spine density, morphology, and long-range axonal projections when visualized with high-resolution microscopy?