| HGNC Family | Intermediate filaments |
| Name | keratin 40, type I |
| Description | This gene encodes a member of the type I (acidic) keratin family, which belongs to the superfamily of intermediate filament (IF) proteins. Keratins are heteropolymeric structural proteins which form the intermediate filament. These filaments, along with actin microfilaments and microtubules, compose the cytoskeleton of epithelial cells. The type I keratin genes are clustered in a region of chromosome 17q12-q21. [provided by RefSeq, Jul 2009] |
| Summary |
{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n Keratin‐40 (KRT40) is emerging as an important type I keratin that contributes to the structural integrity and specialized functions of epithelial‐derived tissues. In the context of uromodulin processing, KRT40 has been investigated for its potential regulatory role in kidney physiology, with alterations in its expression possibly affecting uromodulin maturation and excretion."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " In lung cancer, KRT40 is one of a small panel of epithelial markers employed in a novel single‐sample predictor for histological classification and fusion gene detection in non–small cell lung cancer; here its expression contributes to the gene‐expression signature that distinguishes different tumor subtypes."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n \n "}, {"type": "p", "children": [{"type": "t", "text": "\n In studies of hair biology and livestock, KRT40 has been identified as a hub gene within a co‐expression module associated with hair follicle development, cell cycle regulation, and melanogenesis, thus implicating it in the formation and maintenance of hair structures in species such as yak."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": " In parallel, analyses in sheep have shown that transcripts for KRT40 are confined to the fibre cuticle, suggesting that it plays a specialized role in the structural compartmentalization of wool and hair fibers."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n \n "}, {"type": "p", "children": [{"type": "t", "text": "\n Moreover, in gastric cancer, differential expression of keratin 40 has been correlated with patient prognosis, suggesting that it may serve as a potential biomarker for disease progression."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": " Finally, forensic proteomic analyses of hair shafts have revealed that KRT40 is one of several abundant keratins detectable in hair. Its presence is robust in longer hair samples but may be less reliably identified in very short hairs, thereby influencing its utility in forensic investigations."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n \n "}, {"type": "p", "children": [{"type": "t", "text": "\n Collectively, these studies highlight that KRT40 functions both as a structural component in differentiated epithelial cells—particularly in hair and wool fibre formation—and as a molecular marker with potential diagnostic and prognostic value in cancer and renal physiology.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Christina B Joseph, Marta Mariniello, Ayumi Yoshifuji, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Meta-GWAS Reveals Novel Genetic Variants Associated with Urinary Excretion of Uromodulin."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Am Soc Nephrol (2022)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1681/ASN.2021040491"}], "href": "https://doi.org/10.1681/ASN.2021040491"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "35228297"}], "href": "https://pubmed.ncbi.nlm.nih.gov/35228297"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Anna Karlsson, Helena Cirenajwis, Kajsa Ericson-Lindquist, et al. "}, {"type": "b", "children": [{"type": "t", "text": "A combined gene expression tool for parallel histological prediction and gene fusion detection in non-small cell lung cancer."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Sci Rep (2019)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/s41598-019-41585-4"}], "href": "https://doi.org/10.1038/s41598-019-41585-4"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "30914778"}], "href": "https://pubmed.ncbi.nlm.nih.gov/30914778"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Qi Bao, Xiaolan Zhang, Pengjia Bao, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Genome-wide identification, characterization, and expression analysis of keratin genes (KRTs) family in yak (Bos grunniens)."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Gene (2022)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.gene.2022.146247"}], "href": "https://doi.org/10.1016/j.gene.2022.146247"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "35085710"}], "href": "https://pubmed.ncbi.nlm.nih.gov/35085710"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Zhidong Yu, Janet E Wildermoth, Olivia A M Wallace, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Annotation of sheep keratin intermediate filament genes and their patterns of expression."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Exp Dermatol (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1111/j.1600-0625.2011.01274.x"}], "href": "https://doi.org/10.1111/j.1600-0625.2011.01274.x"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21554405"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21554405"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Wenjing Chen, Weiteng Zhang, Ruisen Wu, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Identification of biomarkers associated with histological grade and prognosis of gastric cancer by co-expression network analysis."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Oncol Lett (2019)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.3892/ol.2019.10869"}], "href": "https://doi.org/10.3892/ol.2019.10869"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "31612058"}], "href": "https://pubmed.ncbi.nlm.nih.gov/31612058"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Katherine F Jones, Traci L Carlson, Brian A Eckenrode, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Assessing protein sequencing in human single hair shafts of decreasing lengths."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Forensic Sci Int Genet (2020)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.fsigen.2019.102145"}], "href": "https://doi.org/10.1016/j.fsigen.2019.102145"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "31590061"}], "href": "https://pubmed.ncbi.nlm.nih.gov/31590061"}]}]}]}
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| Synonyms | K40, KA36, CK-40 |
| Proteins | K1C40_HUMAN |
| NCBI Gene ID | 125115 |
| API | |
| Download Associations | |
| Predicted Functions |
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| Co-expressed Genes |
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| Expression in Tissues and Cell Lines |
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KRT40 has 1,368 functional associations with biological entities spanning 9 categories (molecular profile, organism, functional term, phrase or reference, disease, phenotype or trait, chemical, structural feature, cell line, cell type or tissue, gene, protein or microRNA, sequence feature) extracted from 70 datasets.
Click the + buttons to view associations for KRT40 from the datasets below.
If available, associations are ranked by standardized value
| Dataset | Summary | |
|---|---|---|
| Allen Brain Atlas Adult Mouse Brain Tissue Gene Expression Profiles | tissues with high or low expression of KRT40 gene relative to other tissues from the Allen Brain Atlas Adult Mouse Brain Tissue Gene Expression Profiles dataset. | |
| Allen Brain Atlas Aging Dementia and Traumatic Brain Injury Tissue Sample Gene Expression Profiles | tissue samples with high or low expression of KRT40 gene relative to other tissue samples from the Allen Brain Atlas Aging Dementia and Traumatic Brain Injury Tissue Sample Gene Expression Profiles dataset. | |
| Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by Microarray | tissue samples with high or low expression of KRT40 gene relative to other tissue samples from the Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by Microarray dataset. | |
| CCLE Cell Line Gene CNV Profiles | cell lines with high or low copy number of KRT40 gene relative to other cell lines from the CCLE Cell Line Gene CNV Profiles dataset. | |
| CCLE Cell Line Gene Expression Profiles | cell lines with high or low expression of KRT40 gene relative to other cell lines from the CCLE Cell Line Gene Expression Profiles dataset. | |
| ChEA Transcription Factor Binding Site Profiles | transcription factor binding site profiles with transcription factor binding evidence at the promoter of KRT40 gene from the CHEA Transcription Factor Binding Site Profiles dataset. | |
| ChEA Transcription Factor Targets | transcription factors binding the promoter of KRT40 gene in low- or high-throughput transcription factor functional studies from the CHEA Transcription Factor Targets dataset. | |
| ChEA Transcription Factor Targets 2022 | transcription factors binding the promoter of KRT40 gene in low- or high-throughput transcription factor functional studies from the CHEA Transcription Factor Targets 2022 dataset. | |
| COMPARTMENTS Curated Protein Localization Evidence Scores | cellular components containing KRT40 protein from the COMPARTMENTS Curated Protein Localization Evidence Scores dataset. | |
| COMPARTMENTS Text-mining Protein Localization Evidence Scores | cellular components co-occuring with KRT40 protein in abstracts of biomedical publications from the COMPARTMENTS Text-mining Protein Localization Evidence Scores dataset. | |
| COMPARTMENTS Text-mining Protein Localization Evidence Scores 2025 | cellular components co-occuring with KRT40 protein in abstracts of biomedical publications from the COMPARTMENTS Text-mining Protein Localization Evidence Scores 2025 dataset. | |
| COSMIC Cell Line Gene CNV Profiles | cell lines with high or low copy number of KRT40 gene relative to other cell lines from the COSMIC Cell Line Gene CNV Profiles dataset. | |
| COSMIC Cell Line Gene Mutation Profiles | cell lines with KRT40 gene mutations from the COSMIC Cell Line Gene Mutation Profiles dataset. | |
| dbGAP Gene-Trait Associations | traits associated with KRT40 gene in GWAS and other genetic association datasets from the dbGAP Gene-Trait Associations dataset. | |
| DepMap CRISPR Gene Dependency | cell lines with fitness changed by KRT40 gene knockdown relative to other cell lines from the DepMap CRISPR Gene Dependency dataset. | |
| DISEASES Experimental Gene-Disease Association Evidence Scores 2025 | diseases associated with KRT40 gene in GWAS datasets from the DISEASES Experimental Gene-Disease Assocation Evidence Scores 2025 dataset. | |
| DISEASES Text-mining Gene-Disease Association Evidence Scores | diseases co-occuring with KRT40 gene in abstracts of biomedical publications from the DISEASES Text-mining Gene-Disease Assocation Evidence Scores dataset. | |
| DISEASES Text-mining Gene-Disease Association Evidence Scores 2025 | diseases co-occuring with KRT40 gene in abstracts of biomedical publications from the DISEASES Text-mining Gene-Disease Assocation Evidence Scores 2025 dataset. | |
| DisGeNET Gene-Disease Associations | diseases associated with KRT40 gene in GWAS and other genetic association datasets from the DisGeNET Gene-Disease Associations dataset. | |
| ENCODE Histone Modification Site Profiles | histone modification site profiles with high histone modification abundance at KRT40 gene from the ENCODE Histone Modification Site Profiles dataset. | |
| ENCODE Transcription Factor Binding Site Profiles | transcription factor binding site profiles with transcription factor binding evidence at the promoter of KRT40 gene from the ENCODE Transcription Factor Binding Site Profiles dataset. | |
| ENCODE Transcription Factor Targets | transcription factors binding the promoter of KRT40 gene in ChIP-seq datasets from the ENCODE Transcription Factor Targets dataset. | |
| ESCAPE Omics Signatures of Genes and Proteins for Stem Cells | PubMedIDs of publications reporting gene signatures containing KRT40 from the ESCAPE Omics Signatures of Genes and Proteins for Stem Cells dataset. | |
| GAD Gene-Disease Associations | diseases associated with KRT40 gene in GWAS and other genetic association datasets from the GAD Gene-Disease Associations dataset. | |
| GeneRIF Biological Term Annotations | biological terms co-occuring with KRT40 gene in literature-supported statements describing functions of genes from the GeneRIF Biological Term Annotations dataset. | |
| GEO Signatures of Differentially Expressed Genes for Diseases | disease perturbations changing expression of KRT40 gene from the GEO Signatures of Differentially Expressed Genes for Diseases dataset. | |
| GEO Signatures of Differentially Expressed Genes for Gene Perturbations | gene perturbations changing expression of KRT40 gene from the GEO Signatures of Differentially Expressed Genes for Gene Perturbations dataset. | |
| GEO Signatures of Differentially Expressed Genes for Small Molecules | small molecule perturbations changing expression of KRT40 gene from the GEO Signatures of Differentially Expressed Genes for Small Molecules dataset. | |
| GEO Signatures of Differentially Expressed Genes for Transcription Factor Perturbations | transcription factor perturbations changing expression of KRT40 gene from the GEO Signatures of Differentially Expressed Genes for Transcription Factor Perturbations dataset. | |
| GEO Signatures of Differentially Expressed Genes for Viral Infections | virus perturbations changing expression of KRT40 gene from the GEO Signatures of Differentially Expressed Genes for Viral Infections dataset. | |
| GO Biological Process Annotations 2023 | biological processes involving KRT40 gene from the curated GO Biological Process Annotations 2023 dataset. | |
| GO Biological Process Annotations 2025 | biological processes involving KRT40 gene from the curated GO Biological Process Annotations2025 dataset. | |
| GO Cellular Component Annotations 2015 | cellular components containing KRT40 protein from the curated GO Cellular Component Annotations 2015 dataset. | |
| GO Cellular Component Annotations 2025 | cellular components containing KRT40 protein from the curated GO Cellular Component Annotations 2025 dataset. | |
| GO Molecular Function Annotations 2015 | molecular functions performed by KRT40 gene from the curated GO Molecular Function Annotations 2015 dataset. | |
| GTEx eQTL 2025 | SNPs regulating expression of KRT40 gene from the GTEx eQTL 2025 dataset. | |
| GTEx Tissue Gene Expression Profiles | tissues with high or low expression of KRT40 gene relative to other tissues from the GTEx Tissue Gene Expression Profiles dataset. | |
| GTEx Tissue Gene Expression Profiles 2023 | tissues with high or low expression of KRT40 gene relative to other tissues from the GTEx Tissue Gene Expression Profiles 2023 dataset. | |
| GWAS Catalog SNP-Phenotype Associations 2025 | phenotypes associated with KRT40 gene in GWAS datasets from the GWAS Catalog SNP-Phenotype Associations 2025 dataset. | |
| Heiser et al., PNAS, 2011 Cell Line Gene Expression Profiles | cell lines with high or low expression of KRT40 gene relative to other cell lines from the Heiser et al., PNAS, 2011 Cell Line Gene Expression Profiles dataset. | |
| HPA Tissue Gene Expression Profiles | tissues with high or low expression of KRT40 gene relative to other tissues from the HPA Tissue Gene Expression Profiles dataset. | |
| HPA Tissue Protein Expression Profiles | tissues with high or low expression of KRT40 protein relative to other tissues from the HPA Tissue Protein Expression Profiles dataset. | |
| HPM Cell Type and Tissue Protein Expression Profiles | cell types and tissues with high or low expression of KRT40 protein relative to other cell types and tissues from the HPM Cell Type and Tissue Protein Expression Profiles dataset. | |
| InterPro Predicted Protein Domain Annotations | protein domains predicted for KRT40 protein from the InterPro Predicted Protein Domain Annotations dataset. | |
| JASPAR Predicted Human Transcription Factor Targets 2025 | transcription factors regulating expression of KRT40 gene predicted using known transcription factor binding site motifs from the JASPAR Predicted Human Transcription Factor Targets dataset. | |
| JASPAR Predicted Mouse Transcription Factor Targets 2025 | transcription factors regulating expression of KRT40 gene predicted using known transcription factor binding site motifs from the JASPAR Predicted Mouse Transcription Factor Targets 2025 dataset. | |
| JASPAR Predicted Transcription Factor Targets | transcription factors regulating expression of KRT40 gene predicted using known transcription factor binding site motifs from the JASPAR Predicted Transcription Factor Targets dataset. | |
| KEGG Pathways | pathways involving KRT40 protein from the KEGG Pathways dataset. | |
| KEGG Pathways 2026 | pathways involving KRT40 protein from the KEGG Pathways 2026 dataset. | |
| Klijn et al., Nat. Biotechnol., 2015 Cell Line Gene CNV Profiles | cell lines with high or low copy number of KRT40 gene relative to other cell lines from the Klijn et al., Nat. Biotechnol., 2015 Cell Line Gene CNV Profiles dataset. | |
| LOCATE Predicted Protein Localization Annotations | cellular components predicted to contain KRT40 protein from the LOCATE Predicted Protein Localization Annotations dataset. | |
| MotifMap Predicted Transcription Factor Targets | transcription factors regulating expression of KRT40 gene predicted using known transcription factor binding site motifs from the MotifMap Predicted Transcription Factor Targets dataset. | |
| PerturbAtlas Signatures of Differentially Expressed Genes for Gene Perturbations | gene perturbations changing expression of KRT40 gene from the PerturbAtlas Signatures of Differentially Expressed Genes for Gene Perturbations dataset. | |
| PerturbAtlas Signatures of Differentially Expressed Genes for Mouse Gene Perturbations | gene perturbations changing expression of KRT40 gene from the PerturbAtlas Signatures of Differentially Expressed Genes for Gene Perturbations dataset. | |
| PFOCR Pathway Figure Associations 2023 | pathways involving KRT40 protein from the PFOCR Pathway Figure Associations 2023 dataset. | |
| PFOCR Pathway Figure Associations 2024 | pathways involving KRT40 protein from the Wikipathways PFOCR 2024 dataset. | |
| Reactome Pathways 2024 | pathways involving KRT40 protein from the Reactome Pathways 2024 dataset. | |
| Roadmap Epigenomics Cell and Tissue DNA Methylation Profiles | cell types and tissues with high or low DNA methylation of KRT40 gene relative to other cell types and tissues from the Roadmap Epigenomics Cell and Tissue DNA Methylation Profiles dataset. | |
| Roadmap Epigenomics Histone Modification Site Profiles | histone modification site profiles with high histone modification abundance at KRT40 gene from the Roadmap Epigenomics Histone Modification Site Profiles dataset. | |
| RummaGEO Drug Perturbation Signatures | drug perturbations changing expression of KRT40 gene from the RummaGEO Drug Perturbation Signatures dataset. | |
| RummaGEO Gene Perturbation Signatures | gene perturbations changing expression of KRT40 gene from the RummaGEO Gene Perturbation Signatures dataset. | |
| Tabula Sapiens Gene-Cell Associations | cell types with high or low expression of KRT40 gene relative to other cell types from the Tabula Sapiens Gene-Cell Associations dataset. | |
| TargetScan Predicted Conserved microRNA Targets | microRNAs regulating expression of KRT40 gene predicted using conserved miRNA seed sequences from the TargetScan Predicted Conserved microRNA Targets dataset. | |
| TargetScan Predicted Nonconserved microRNA Targets | microRNAs regulating expression of KRT40 gene predicted using nonconserved miRNA seed sequences from the TargetScan Predicted Nonconserved microRNA Targets dataset. | |
| TCGA Signatures of Differentially Expressed Genes for Tumors | tissue samples with high or low expression of KRT40 gene relative to other tissue samples from the TCGA Signatures of Differentially Expressed Genes for Tumors dataset. | |
| TISSUES Curated Tissue Protein Expression Evidence Scores | tissues with high expression of KRT40 protein from the TISSUES Curated Tissue Protein Expression Evidence Scores dataset. | |
| TISSUES Curated Tissue Protein Expression Evidence Scores 2025 | tissues with high expression of KRT40 protein from the TISSUES Curated Tissue Protein Expression Evidence Scores 2025 dataset. | |
| TISSUES Experimental Tissue Protein Expression Evidence Scores 2025 | tissues with high expression of KRT40 protein in proteomics datasets from the TISSUES Experimental Tissue Protein Expression Evidence Scores 2025 dataset. | |
| TISSUES Text-mining Tissue Protein Expression Evidence Scores | tissues co-occuring with KRT40 protein in abstracts of biomedical publications from the TISSUES Text-mining Tissue Protein Expression Evidence Scores dataset. | |
| TISSUES Text-mining Tissue Protein Expression Evidence Scores 2025 | tissues co-occuring with KRT40 protein in abstracts of biomedical publications from the TISSUES Text-mining Tissue Protein Expression Evidence Scores 2025 dataset. | |
