Details for: SPRR1B

Gene ID: 6699

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: SPRR1B

Ensembl ID: ENSG00000169469

Description: small proline rich protein 1B

Selected Context(s):  Overall

Cell Significance Landscape

Contexts:

Associated with

Significant Cells

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

  • keratinocyte CL0000312
    CSI 9.22
    rCSI 7.73%
    PRS 98.55
  • squamous epithelial cell CL0000076
    CSI 5.02
    rCSI 11.92%
    PRS 97.28
  • epithelial cell CL0000066
    CSI 3.98
    rCSI 6.12%
    PRS 95.78
  • nasal mucosa goblet cell CL0002480
    CSI 3.55
    rCSI 4.12%
    PRS 98.69
  • club cell CL0000158
    CSI 3.3
    rCSI 4.84%
    PRS 99.2
  • conjunctival epithelial cell CL1000432
    CSI 3.03
    rCSI 4.64%
    PRS 98.87
  • respiratory hillock cell CL4030023
    CSI 2.74
    rCSI 4.88%
    PRS 99.53
  • epithelial cell of esophagus CL0002252
    CSI 1.87
    rCSI 18.49%
    PRS 97.76

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 [SPRR1B](/details-gene/6699) (Small Proline Rich Protein 1B), also known as Cornifin-B, is a protein-coding gene located on chromosome 1q21.3. It functions primarily as a structural molecule and is a key precursor protein in the formation of the cornified envelope in terminally differentiating stratified squamous epithelia. Its expression is highly specific and abundant in [keratinocytes](/details-cell/CL0000312), where it plays an essential role in establishing the protective barrier of the epidermis. Functionally, it is involved in biological processes such as [epidermis development](/details-cell/GO:0008544), [keratinization](/details-cell/GO:0031424), and [peptide cross-linking](/details-cell/GO:0018149), contributing to the structural integrity and resilience of epithelial tissues. ## Cellular Roles and Expression Landscape The expression profile of [SPRR1B](/details-gene/6699) underscores its specialized role in forming protective epithelial barriers. **Overall**, the gene shows dominant and highly significant expression in [keratinocytes](/details-cell/CL0000312) (CSI: 9.22), establishing it as a hallmark marker for this cell type. Its significance extends to other cells involved in creating stratified barriers, including [squamous epithelial cell](/details-cell/CL0000076) (CSI: 5.02), [epithelial cell](/details-cell/CL0000066) (CSI: 3.98), and [epithelial cell of esophagus](/details-cell/CL0002252) (CSI: 1.87). Beyond the skin and esophagus, [SPRR1B](/details-gene/6699) is also significantly expressed in specialized epithelial cells of mucosal and respiratory surfaces. These include [nasal mucosa goblet cell](/details-cell/CL0002480) (CSI: 3.55), [club cell](/details-cell/CL0000158) (CSI: 3.30), [conjunctival epithelial cell](/details-cell/CL1000432) (CSI: 3.03), and [respiratory hillock cell](/details-cell/CL4030023) (CSI: 2.74). This pattern suggests that its function in barrier formation is not limited to the epidermis but is a conserved mechanism across various epithelial tissues exposed to the external environment. The available data points towards a highly specific function within epithelial lineages. ## Pathways and Molecular Function The molecular function of [SPRR1B](/details-gene/6699) is tightly linked to its high expression in epidermal and epithelial cells. As a key player in `Structural molecule activity` ([GO:0005198](https://www.ebi.ac.uk/QuickGO/term/GO:0005198)), it is an integral component of the `Cornified envelope` ([GO:0001533](https://www.ebi.ac.uk/QuickGO/term/GO:0001533)). This is consistent with its deep involvement in the Reactome pathway `Formation of the cornified envelope` ([R-HSA-6809371](https://reactome.org/content/detail/R-HSA-6809371)). The protein product is a substrate for transglutaminases, which catalyze the formation of isopeptide bonds during the final stages of [keratinocyte differentiation](/details-cell/GO:0030216), a process described by the GO term `Peptide cross-linking` ([GO:0018149](https://www.ebi.ac.uk/QuickGO/term/GO:0018149)). This cross-linking is fundamental to the process of `Keratinization` ([R-HSA-6805567](https://reactome.org/content/detail/R-HSA-6805567)), which ultimately creates the insoluble, resilient outer layer of the skin. Research has characterized it as a "pancornulin," a group of precursors with bifunctional capabilities in this cross-linking process ([Link](https://doi.org/10.1111/1523-1747.ep12612759)). Its expression is also known to be stimulated by UV radiation and regulated by phorbol esters and cyclic AMP, suggesting its role in both normal development and stress responses ([Link](https://doi.org/10.1128/mcb.8.5.2195-2203.1988), [Link](https://doi.org/10.1016/s0021-9258(18)82081-6)). ## Research Directions The highly specific expression and known function of [SPRR1B](/details-gene/6699) in epithelial integrity provide a foundation for several targeted research avenues. ### Proposed Hypotheses: 1. Given that its expression is stimulated by UV light ([Link](https://doi.org/10.1128/mcb.8.5.2195-2203.1988)), [SPRR1B](/details-gene/6699) likely functions as an adaptive, stress-response protein critical for reinforcing the epidermal barrier and promoting recovery following environmental damage. 2. The significant expression of [SPRR1B](/details-gene/6699) in non-skin epithelial tissues, such as in [nasal mucosa goblet cell](/details-cell/CL0002480) and [club cell](/details-cell/CL0000158), suggests a conserved role in protecting mucosal barriers against inhaled pathogens, allergens, and pollutants. 3. Dysregulation of [SPRR1B](/details-gene/6699) expression may be a contributing factor in the pathogenesis of inflammatory skin diseases like psoriasis or atopic dermatitis, where barrier function is compromised, or in squamous cell carcinomas where differentiation programs are altered. ### Suggested Experimental Approach: To test the hypothesis that [SPRR1B](/details-gene/6699) is a critical component of the UV stress response, one could employ a 3D human skin equivalent model. In this model, [SPRR1B](/details-gene/6699) expression in primary human [keratinocytes](/details-cell/CL0000312) would be knocked down using siRNA or knocked out via CRISPR-Cas9 prior to tissue generation. Control and deficient tissues would then be exposed to a controlled, sub-lethal dose of UVB radiation. Key experimental readouts would include measuring transepithelial electrical resistance (TEER) to quantify barrier integrity, assessing cell death via TUNEL staining, and analyzing the expression of other cornified envelope and stress-response proteins via qPCR and Western blot to determine compensatory mechanisms. ### Therapeutic Potential: Due to its fundamental structural role, [SPRR1B](/details-gene/6699) is unlikely to be a suitable target for direct inhibition, as this would predictably compromise epithelial barrier integrity and lead to significant toxicity. However, its highly specific expression profile makes it a potential biomarker for assessing the status of epithelial differentiation and barrier function in skin diseases or cancers. Therapeutic strategies might instead focus on modulating its expression levels; for example, targeted *activation* or delivery of [SPRR1B](/details-gene/6699) could be explored as a regenerative approach for conditions characterized by a defective epidermal barrier.

Genular Protein ID: 1557643009

Symbol: SPR1B_HUMAN

Name: Cornifin-B

UniProtKB Accession Codes:

P22528 B2R5H7 P22529 P22530 Q5T524

Database IDs:

AGR 1 AlphaFoldDB 1 Antibodypedia 1 Bgee 1 BioGRID 1 BioGRID-ORCS 1 BioMuta 1 CCDS 1 CTD 1 ChiTaRS 1 DMDM 1 DNASU 1 DisGeNET 1 EMBL 8 Ensembl 1 GO 8 GeneCards 1 GeneTree 1 GeneWiki 1 GenomeRNAi 1 HGNC 1 HOGENOM 1 HPA 1 InParanoid 1 IntAct 1 KEGG 1 MANE-Select 1 MIM 1 MINT 1 MassIVE 1 NCBI Taxonomy 1 OMA 1 OpenTargets 1 OrthoDB 1 PIR 1 PRINTS 1 PRO 1 PathwayCommons 1 PaxDb 1 PeptideAtlas 1 Pfam 1 PharmGKB 1 Pharos 1 PhosphoSitePlus 1 PhylomeDB 1 Proteomes 1 ProteomicsDB 1 Pumba 1 RNAct 1 Reactome 1 RefSeq 1 SIGNOR 1 STRING 1 SignaLink 1 TreeFam 1 UCSC 1 VEuPathDB 1 eggNOG 1 iPTMnet 1 jPOST 1 neXtProt 1

Citations:

PubMed ID: 3133554

Title: Isolation, characterization, and UV-stimulated expression of two families of genes encoding polypeptides of related structure in human epidermal keratinocytes.

PubMed ID: 3133554

DOI: 10.1128/mcb.8.5.2195-2203.1988

PubMed ID: 8388378

Title: Isolation and characterization of the human spr1 gene and its regulation of expression by phorbol ester and cyclic AMP.

PubMed ID: 8388378

DOI: 10.1016/s0021-9258(18)82081-6

PubMed ID: 14702039

Title: Complete sequencing and characterization of 21,243 full-length human cDNAs.

PubMed ID: 14702039

DOI: 10.1038/ng1285

PubMed ID: 16710414

Title: The DNA sequence and biological annotation of human chromosome 1.

PubMed ID: 16710414

DOI: 10.1038/nature04727

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: 7829876

Title: The pancornulins: a group of small proline rich-related cornified envelope precursors with bifunctional capabilities in isopeptide bond formation.

PubMed ID: 7829876

DOI: 10.1111/1523-1747.ep12612759

Sequence Information:

  • Length: 89
  • Mass: 9888
  • Checksum: 8B10DF32103496D3
  • Sequence:
    • MSSQQQKQPC TPPPQLQQQQ VKQPCQPPPQ EPCIPKTKEP CHPKVPEPCH PKVPEPCQPK 
VPEPCHPKVP EPCPSIVTPA PAQQKTKQK