Details for: CL0000748

Cell ID: CL0000748

Cell Name: retinal bipolar neuron

Description: A bipolar neuron found in the retina and having connections with photoreceptors cells and neurons in the inner plexiform layer.

Synonyms: BC, BCs, BPs

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 retinal bipolar 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 retinal bipolar 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 retinal bipolar 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 retinal bipolar 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:  retinal bipolar neuron (CL0000748)

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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 [retinal bipolar neuron](/details-cell/CL0000748) is a specialized interneuron critical for transmitting visual signals from photoreceptor cells to ganglion cells within the retina. Analysis of its gene expression profile reveals a cell singularly defined by its role in glutamatergic neurotransmission and the maintenance of precise synaptic architecture. The high expression specificity, indicated by the Z-score based Cell Significance Index (CSI), of genes encoding glutamate receptors such as [GRM5](/details-gene/2915), ion channels like [TRPM1](/details-gene/4308), and large cell adhesion molecules like [CSMD3](/details-gene/114788) underscores its identity as a finely-tuned component of the visual processing pathway. These markers suggest that the cell's function is equally dependent on its ability to receive and transduce signals as it is on maintaining its specific and complex connections within the retinal layers. ## Key Characteristics and Function The molecular identity of the [retinal bipolar neuron](/details-cell/CL0000748) is dominated by genes involved in synaptic signaling, cell adhesion, and ion homeostasis. **Overall**, the top markers can be functionally grouped to delineate the cell's primary roles. * **Glutamatergic Synaptic Transmission:** A cornerstone of this cell's function is its response to glutamate released from photoreceptors. This is highlighted by the exceptionally high specificity of the metabotropic glutamate receptor [GRM5](/details-gene/2915) (CSI: 51.22) and multiple ionotropic glutamate receptors, including [GRIK1](/details-gene/2897) (kainate receptor) and [GRIA4](/details-gene/2893) (AMPA receptor). The presence of [GRID1](/details-gene/2894) further supports a complex postsynaptic scaffold tailored for glutamate signaling. This diverse receptor profile is consistent with the known functional segregation of bipolar cells into different signaling pathways (e.g., ON and OFF channels). * **Neuronal Architecture and Cell Adhesion:** The neuron's identity is strongly defined by a suite of cell adhesion and structural molecules, suggesting their critical role in establishing and maintaining the precise laminar organization of the retina. Genes such as [CSMD3](/details-gene/114788), [CNTNAP5](/details-gene/129684), [DSCAM](/details-gene/1826), and [OPCML](/details-gene/4978) show high expression specificity. [DSCAM](/details-gene/1826), in particular, is known to be involved in neuronal wiring and self-avoidance ([Link](https://doi.org/10.1093/hmg/7.2.227)), which is essential for forming non-overlapping dendritic and axonal fields. * **Signal Transduction and Ion Homeostasis:** The specific expression of ion channels is critical for translating photoreceptor signals into a neuronal response. The transient receptor potential channel [TRPM1](/details-gene/4308) (CSI: 37.45) is a well-established marker for ON-bipolar cells, where it is essential for the light-evoked depolarization cascade. The high specificity of the sodium/calcium exchanger [SLC24A2](/details-gene/25769) further points to tight regulation of intracellular calcium, a key second messenger in these neurons. * **Neural Development and Maintenance:** The high specificity of the neuregulin [NRG3](/details-gene/10718) suggests a role in neuronal development or plasticity, potentially mediating cell-cell signaling via ErbB receptors to ensure neuron survival and function within the retinal circuit ([Link](https://doi.org/10.1073/pnas.94.18.9562)). * **Distinct Metabolic and Housekeeping Profile:** The anti-marker profile provides significant insight into what this cell is not. The strong negative CSI for numerous genes involved in core cellular processes, such as mitochondrial respiration ([COX3](/details-gene/4514), [ND1](/details-gene/4535), [ATP5F1E](/details-gene/514)) and translation ([PABPC1](/details-gene/26986), [EEF1B2](/details-gene/1933)), suggests a highly specialized and perhaps lower basal metabolic and protein synthesis rate compared to other cells in the tissue. This may reflect an adaptation to its unique signaling properties, which rely on graded potentials rather than metabolically expensive action potentials. ## Clinical Significance and Contextual Roles The specific gene signature of the [retinal bipolar neuron](/details-cell/CL0000748) implicates it in several inherited and complex neurological disorders. The **Overall** context analysis highlights genes whose dysfunction has direct clinical relevance. The most direct link is through [TRPM1](/details-gene/4308), mutations in which are a known cause of autosomal recessive congenital stationary night blindness. This condition is characterized by a loss of the ON-bipolar cell pathway function, underscoring the critical and non-redundant role of this specific gene in human vision. Furthermore, several of the top specificity markers are associated with broader neurodevelopmental and neurological conditions. [DSCAM](/details-gene/1826) is located in the Down syndrome critical region on chromosome 21 and is implicated in the neurodevelopmental abnormalities associated with the syndrome ([Link](https://doi.org/10.1093/hmg/7.2.227)). The high specificity of [CSMD3](/details-gene/114788) in these cells is notable, as this gene has been linked to benign adult familial myoclonic epilepsy ([Link](https://doi.org/10.1016/s0006-291x(03)01555-9)). This suggests that while [retinal bipolar neurons](/details-cell/CL0000748) may not be the primary site of pathology in these CNS disorders, they may share a common molecular vulnerability or developmental pathway. The array of glutamate receptors ([GRM5](/details-gene/2915), [GRIK1](/details-gene/2897), [GRIA4](/details-gene/2893)) that define this cell type are also well-established therapeutic targets and mediators in excitotoxicity, a process implicated in retinal damage in diseases like glaucoma and diabetic retinopathy. The specific expression of these receptors makes the [retinal bipolar neuron](/details-cell/CL0000748) a potentially key player and a vulnerable target in the progression of these blinding diseases. ## Potential Mechanisms and Research Directions 1. **Hypothesis:** The highly specific co-expression of a diverse set of cell adhesion molecules ([CSMD3](/details-gene/114788), [CNTNAP5](/details-gene/129684), [DSCAM](/details-gene/1826)) suggests that [retinal bipolar neurons](/details-cell/CL0000748) use a complex combinatorial code of surface proteins to establish and maintain their precise synaptic stratification and connectivity within the inner plexiform layer. This molecular code is likely fundamental for segregating distinct visual information channels (e.g., motion, color, contrast) that originate from different bipolar cell subtypes. * **Surprising Findings:** The prominence of these large, structurally complex adhesion molecules as top identity markers, with specificity scores comparable to key neurotransmitter receptors, is remarkable. It elevates their role from simple structural support to being core functional components that are as defining for the cell as its ability to process glutamate signals. * **Testable Questions:** Does the subtype-specific expression of [CSMD3](/details-gene/114788), [CNTNAP5](/details-gene/129684), and [DSCAM](/details-gene/1826) correlate with the known laminar termination patterns of different bipolar cell axons in the inner plexiform layer? Furthermore, would conditional knockout of these genes in developing mouse retinas disrupt this lamination and lead to measurable deficits in specific visual processing tasks? 2. **Hypothesis:** The strong negative CSI scores for multiple core mitochondrial and translational machinery genes (e.g., [ND1](/details-gene/4535), [COX7C](/details-gene/1350), [PABPC1](/details-gene/26986)) suggest that [retinal bipolar neurons](/details-cell/CL0000748) operate in a state of uniquely low metabolic and biosynthetic activity relative to surrounding cell types. This may be an evolutionary adaptation for energy efficiency, as these cells signal via less energetically demanding graded potentials and must function continuously throughout life with limited turnover. * **Surprising Findings:** For a neuron, which is typically considered a high-energy-demand cell, to be characterized by the relative suppression of genes for oxidative phosphorylation and protein synthesis is highly unexpected. This finding challenges the general model of neuronal metabolism and suggests a unique bioenergetic strategy for this specific interneuron. * **Testable Questions:** How does the rate of oxygen consumption and protein synthesis in isolated [retinal bipolar neurons](/details-cell/CL0000748) compare to that of retinal ganglion cells (which fire action potentials) or photoreceptors (with their high metabolic load of the dark current)? Could this lower metabolic state make them paradoxically more vulnerable to certain metabolic stresses found in diseases like diabetic retinopathy?