Details for: FDCSP

Gene ID: 260436

Gene Type:  Protein-coding  - A gene that serves as a template for producing a messenger RNA (mRNA) molecule, which is then translated into a functional protein.

Symbol: FDCSP

Ensembl ID: ENSG00000181617

Description: follicular dendritic cell secreted protein

Selected Context(s):  Overall

Cell Significance Landscape

Contexts:

Associated with

Significant Cells

Cell Significance Index (CSI) scores for the chosen context(s)

  • epithelial cell CL0000066
    CSI 11.32
    rCSI 17.4%
    PRS 89.38
  • acinar cell CL0000622
    CSI 7.22
    rCSI 10.59%
    PRS 98.53
  • duct epithelial cell CL0000068
    CSI 5.16
    rCSI 7.55%
    PRS 98.39
  • mammary gland epithelial cell CL0002327
    CSI 5.04
    rCSI 17.68%
    PRS 98.57
  • follicular dendritic cell CL0000442
    CSI 3.24
    rCSI 52.11%
    PRS 98.02
  • mucus secreting cell CL0000319
    CSI 2.71
    rCSI 4.31%
    PRS 98.55
  • myoepithelial cell CL0000185
    CSI 2.54
    rCSI 6.43%
    PRS 98
  • serous secreting cell CL0000313
    CSI 2.5
    rCSI 12.65%
    PRS 97.92
  • CD8-positive, alpha-beta memory T cell, CD45RO-positive CL0001203
    CSI 2.15
    rCSI 2.61%
    PRS 82.99
  • mesenchymal lymphangioblast CL0005021
    CSI 1.41
    rCSI 37.14%
    PRS 98.24
  • acinar cell of salivary gland CL0002623
    CSI 1.33
    rCSI 30.96%
    PRS 98.57
  • helper T cell CL0000912
    CSI 1.1
    rCSI 1.56%
    PRS 92.6

Cell ID: Standard Cell Ontology term used for mapping and comparing cells across experiments. Ensures consistency in analyzing cellular functions across tissues.
Fold Change: Represents the ratio of the current Cell Significance Index to the Cell Significance Index Threshold, indicating how much the gene expression has changed compared to a baseline.
Cell Significance Index: Reflects how strongly a gene is expressed in this specific cell.

Cell ID: Standard Cell Ontology term used for mapping and comparing cells across experiments. Ensures consistency in analyzing cellular functions across tissues.
Fold Change: Represents the ratio of the current Cell Significance Index to the Cell Significance Index Threshold, indicating how much the gene expression has changed compared to a baseline.
Cell Significance Index: Reflects how strongly a gene is expressed in this cell type. Calculated using techniques like effect size estimation and bootstrapping for reliability.

Cell ID: Standard Cell Ontology term used for mapping and comparing cells across experiments. Ensures consistency in analyzing cellular functions across tissues.
Fold Change: Represents the ratio of the current Cell Significance Index to the Cell Significance Index Threshold, indicating how much the gene expression has changed compared to a baseline.
Cell Significance Index: Reflects how strongly a gene is expressed in this cell type. Calculated using techniques like effect size estimation and bootstrapping for reliability.
Network Configuration

Explore relationships of the current gene. Select an Interaction Source: 'ONTOLOGY' for shared pathways (GO/Reactome) or 'STRING' for protein-protein interactions. Further refine by selecting context genes and comparing Cell Significance Index (CSI) scores between baseline and target cell types and their specific contexts.

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  • Query Gene
  • Node Color (Target Cell CSI, relative to current network):
    • Very High
    • High
    • Medium
    • Low
    • Very Low
    • CSI N/A
  • Node Size: Proportional to Target Cell CSI magnitude
  • STRING PPI Edge
  • Shared Pathway Edge (ONTOLOGY)

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Other Information

This section provides additional information about the gene, including a description generated by an AI language model and details about associated proteins.

## Summary [FDCSP](/details-gene/260436) (Follicular Dendritic Cell Secreted Protein) is a protein-coding gene located on chromosome 4q13.3. As its name and functional annotation suggest, it encodes a secreted protein found in the [extracellular region (GO:0005576)](https://www.ebi.ac.uk/QuickGO/term/GO:0005576) that is involved in [protein binding (GO:0005515)](https://www.ebi.ac.uk/QuickGO/term/GO:0005515). While originally identified in [follicular dendritic cells](/details-cell/CL0000442) within lymphoid tissues ([Link](https://doi.org/10.4049/jimmunol.169.5.2381)), a broader analysis of its expression landscape reveals its most significant role is as a marker for various secretory epithelial cell lineages, including [epithelial cells](/details-cell/CL0000066) and [acinar cells](/details-cell/CL0000622). This suggests a primary function related to glandular secretion and epithelial biology, with a potential secondary role in the immune system. ## Cellular Roles and Expression Landscape **Overall**, the expression profile of [FDCSP](/details-gene/260436) is predominantly associated with secretory epithelial tissues. The gene shows the highest cell significance index in [epithelial cell](/details-cell/CL0000066) (CSI: 11.32), followed by specialized secretory cells such as [acinar cell](/details-cell/CL0000622) (CSI: 7.22), [duct epithelial cell](/details-cell/CL0000068) (CSI: 5.16), and [mammary gland epithelial cell](/details-cell/CL0002327) (CSI: 5.04). This strong association is further supported by its significance in other secretory cell types like [mucus secreting cell](/details-cell/CL0000319) and [serous secreting cell](/details-cell/CL0000313). Interestingly, despite its name, [FDCSP](/details-gene/260436) shows a more moderate significance score in [follicular dendritic cells](/details-cell/CL0000442) (CSI: 3.24) compared to the top epithelial lineages. This indicates that while it is an established product of this immune cell type, its expression is not exclusive to it and is quantitatively more pronounced in other contexts. The gene also demonstrates a measurable, albeit lower, significance in certain lymphocyte populations, including [CD8-positive, alpha-beta memory T cell, CD45RO-positive](/details-cell/CL0001203) and [helper T cell](/details-cell/CL0000912), hinting at a potential role in modulating adaptive immune responses. The expression pattern suggests a highly specialized function in secretion, with a likely secondary role in lymphoid tissue microenvironments. ## Pathways and Molecular Function Functionally, [FDCSP](/details-gene/260436) is characterized as an extracellular protein with [protein binding (GO:0005515)](https://www.ebi.ac.uk/QuickGO/term/GO:0005515) capabilities. Its localization to the [extracellular region (GO:0005576)](https://www.ebi.ac.uk/QuickGO/term/GO:0005576) is consistent with its role as a secreted factor. The broad nature of "protein binding" suggests it may act by interacting with other proteins in the extracellular matrix, on cell surfaces, or as a soluble component in bodily fluids to mediate cell-cell communication or structural organization. This is consistent with its high expression in glandular tissues that produce complex secretions. Furthermore, proteomic studies have successfully identified FDCSP as a glycoprotein in human urine, confirming it is secreted into bodily fluids and undergoes post-translational modification ([Link](https://doi.org/10.1074/mcp.m111.013649)). ## Research Directions The dual expression pattern of [FDCSP](/details-gene/260436) in both secretory epithelia and immune microenvironments presents several avenues for future research. A key unanswered question is whether its function differs between these contexts and how its expression is regulated in health versus disease, such as in glandular cancers or autoimmune disorders. Based on the available data, several testable hypotheses can be proposed: 1. Given its high expression in [acinar](/details-cell/CL0000622) and [duct epithelial cells](/details-cell/CL0000068), [FDCSP](/details-gene/260436) may be a critical component of exocrine secretions (e.g., saliva, milk), where it contributes to the fluid's physicochemical properties or antimicrobial activity through its protein-binding function. 2. In the context of lymphoid tissues, [FDCSP](/details-gene/260436) secreted by [follicular dendritic cells](/details-cell/CL0000442) may act as a signaling molecule that influences the survival, selection, or differentiation of B cells and [helper T cells](/details-cell/CL0000912) within the germinal center microenvironment. To test the first hypothesis regarding its role in glandular function, a compelling experimental approach would be to generate an [FDCSP](/details-gene/260436) knockout mouse model. The phenotype of these mice could be assessed by detailed histological analysis of salivary and mammary glands, coupled with proteomic and functional analysis of their respective secretions. Co-immunoprecipitation followed by mass spectrometry on secreted fluids could identify its extracellular binding partners and elucidate its specific molecular role. From a therapeutic standpoint, [FDCSP](/details-gene/260436) holds potential as a non-invasive biomarker. Its secreted nature suggests its levels could be monitored in fluids like saliva or blood to detect or stage diseases of epithelial origin, such as Sjögren's syndrome or breast cancer. If overexpressed on the surface of cancer cells, it could also represent a target for antibody-drug conjugates.

Genular Protein ID: 4243921930

Symbol: FDSCP_HUMAN

Name: Follicular dendritic cell secreted peptide

UniProtKB Accession Codes:

Q8NFU4

Database IDs:

AGR 1 AlphaFoldDB 1 Antibodypedia 1 Bgee 1 BioGRID 1 BioGRID-ORCS 1 BioMuta 1 CCDS 1 CTD 1 ChiTaRS 1 DNASU 1 DisGeNET 1 EMBL 3 Ensembl 1 ExpressionAtlas 1 GO 1 GeneCards 1 GeneTree 1 GenomeRNAi 1 GlyCosmos 1 GlyGen 1 HGNC 1 HOGENOM 1 HPA 1 InParanoid 1 IntAct 1 InterPro 1 KEGG 1 MANE-Select 1 MIM 1 MassIVE 1 NCBI Taxonomy 1 OMA 1 OpenTargets 1 PRO 1 PathwayCommons 1 PaxDb 1 PeptideAtlas 1 Pfam 1 PharmGKB 1 Pharos 1 PhosphoSitePlus 1 PhylomeDB 1 Proteomes 1 ProteomicsDB 1 RNAct 1 RefSeq 1 STRING 1 SignaLink 1 TreeFam 1 UCSC 1 VEuPathDB 1 eggNOG 1 iPTMnet 1 neXtProt 1

Citations:

PubMed ID: 12193705

Title: FDC-SP, a novel secreted protein expressed by follicular dendritic cells.

PubMed ID: 12193705

DOI: 10.4049/jimmunol.169.5.2381

PubMed ID: 12975309

Title: The secreted protein discovery initiative (SPDI), a large-scale effort to identify novel human secreted and transmembrane proteins: a bioinformatics assessment.

PubMed ID: 12975309

DOI: 10.1101/gr.1293003

PubMed ID: 15489334

Title: The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).

PubMed ID: 15489334

DOI: 10.1101/gr.2596504

PubMed ID: 22171320

Title: Human urinary glycoproteomics; attachment site specific analysis of N- and O-linked glycosylations by CID and ECD.

PubMed ID: 22171320

DOI: 10.1074/mcp.m111.013649

Sequence Information:

  • Length: 85
  • Mass: 9700
  • Checksum: 3FEC98BDE883AB07
  • Sequence:
    • MKKVLLLITA ILAVAVGFPV SQDQEREKRS ISDSDELASG FFVFPYPYPF RPLPPIPFPR 
FPWFRRNFPI PIPESAPTTP LPSEK