K25 (K25irs1), K26 (K25irs2), K27 (K25irs3), And K28 (K25irs4) Represent The Type I Inner Root Sheath Keratins Of The Human Hair Follicle

July 2006 in “ Journal of Investigative Dermatology ”

Lutz Langbein, Michael A. Rogers, Silke Praetzel‐Wunder, Burkhard Helmke, Peter Schirmacher, Jürgen Schweizer

inner root sheath keratins K25 K26 K27 K28 K71 alopecia hair follicle IRS layers medulla IRS cuticle mutations hair loss baldness

Studysummary This study describes the expression patterns of type I inner root sheath keratin proteins K25–K28 in human hair follicles, highlighting their distinct distribution within different layers. Our plain-language summary of this paper — not a Tressless recommendation.

The study investigated the expression patterns of type I inner root sheath (IRS) keratins K25 (K25irs1), K26 (K25irs2), K27 (K25irs3), and K28 (K25irs4) in the human hair follicle. It found that K25, K27, and K28 were expressed in all three IRS layers and the medulla, while K26 was restricted to the IRS cuticle. The research clarified the expression of these keratins, which were previously only partially characterized, and aligned their nomenclature with a new consensus system. The study also highlighted the critical role of K71 (K6irs1) in IRS integrity, noting that mutations in this keratin could significantly impact hair follicle function, as evidenced by severe alopecia and structural disturbances in mouse models with K71 mutations.

View this study on jidonline.org →

Discuss this study in the Community →

Research cited in this study

36 / 36 results

research Immunohistochemical Localization of Cytokeratins and Involucrin in Calcifying Epithelioma: Comparative Studies with Normal Skin

49 citations , July 2006 in “British Journal of Dermatology”

This study observed that calcifying epithelioma of Malherbe is composed of tumor cells that differentiate into both hair cortex and outer root sheath, supporting its hair follicle origin.

research Keratinocyte Differentiation in Psoriatic Scalp: Morphology and Expression of Epithelial Keratins

63 citations , July 2006 in “British Journal of Dermatology”

This study found that keratin K17 is induced in the suprabasal layer of psoriatic scalp epidermis during epidermal hyperproliferation, suggesting it is not specific to hair follicles.

research Expression Profiling and Cellular Localization of Genes Associated with the Hair Cycle Induced by Wax Depilation

27 citations , August 2005 in “The journal of investigative dermatology/Journal of investigative dermatology”

This study identified 12 new genes associated with the hair follicle and various stages of the hair cycle in mice, which could lead to novel targets for hair growth or depilation therapies.

research Pili Trianguli Et Canaliculi Is a Defect of Inner Root Sheath Keratinization

8 citations , May 2005 in “The American journal of dermatopathology/American journal of dermatopathology”

This study observed unique ultrastructural changes in a 4-year-old girl with pili trianguli et canaliculi that may affect hair shaft surface characteristics due to inner root sheath alterations.

research Characterization of New Members of the Human Type II Keratin Gene Family and a General Evaluation of the Keratin Gene Domain on Chromosome 12q13.13

92 citations , February 2005 in “Journal of Investigative Dermatology”

research Keratins of the Human Hair Follicle

276 citations , January 2005 in “International review of cytology”

More research is needed to understand how hair keratins work and their role in hair disorders.

The Human Type I Keratin Gene Family: Characterization of New Hair Follicle Specific Members and Evaluation of the Chromosome 17q21.2 Gene Domain

research The Human Type I Keratin Gene Family: Characterization of New Hair Follicle Specific Members and Evaluation of the Chromosome 17q21.2 Gene Domain

70 citations , December 2004 in “Differentiation”

This study identifies six novel keratin genes from the chromosome 17q21.2 region, suggesting their association with hair follicles, while all 27 keratin genes in the domain have been characterized transcriptionally.

research Androgen Regulation of the Human Hair Follicle: The Type I Hair Keratin hHa7 Is a Direct Target Gene in Trichocytes

49 citations , March 2004 in “Journal of Investigative Dermatology”

This study found that the hHa7 gene in hair follicle trichocytes is the first identified to have its expression directly regulated by androgens, suggesting it as a marker for androgen action on hair follicles.

research Functional Analysis of Keratin Components in the Mouse Hair Follicle Inner Root Sheath

23 citations , February 2004 in “British Journal of Dermatology”

Keratin in mouse hair follicles is complex and plays specific roles.

research Hair Keratins And Hair Follicle-Specific Epithelial Keratins

31 citations , January 2004 in “Methods in cell biology”

Hair and follicle keratins differ in structure and expression, especially in cysteine content.

research Type II Epithelial Keratin 6hf (K6hf) Is Expressed in the Companion Layer, Matrix, and Medulla in Anagen-Stage Hair Follicles

60 citations , December 2003 in “Journal of Investigative Dermatology”

This study found that keratin 6hf, a type II keratin, is expressed in specific regions of mouse and human hair and suggests potential interactions with keratin 17, impacting hair development and associated disorders.

research A Small Deletion Hotspot in the Type II Keratin Gene mK6irs1/Krt2-6g on Mouse Chromosome 15, a Candidate for Causing the Wavy Hair of the Caracul (Ca) Mutation

53 citations , October 2003 in “Genetics”

This study identified a mutation hotspot in the caracul (Ca) locus of mice, implicating the mK6irs1/Krt2-6g gene in hair formation and potentially human hair and skin diseases.

research Alopecia in a Novel Mouse Model RCO3 Is Caused by mK6irs1 Deficiency

42 citations , September 2003 in “Journal of Investigative Dermatology”

A missing mK6irs1 gene causes hair loss in mice.

research K6irs1, K6irs2, K6irs3, And K6irs4 Represent The Inner-Root-Sheath-Specific Type II Epithelial Keratins Of The Human Hair Follicle

130 citations , April 2003 in “Journal of Investigative Dermatology”

This study reports the cloning and expression details of two new human type II keratins, K6irs3 and K6irs4, in the hair follicle's inner root sheath, suggesting a distinct functional role related to hair structure.

research A Novel Epithelial Keratin, hK6irs1, Is Expressed Differentially in All Layers of the Inner Root Sheath, Including Specialized Huxley Cells of the Human Hair Follicle

86 citations , May 2002 in “Journal of Investigative Dermatology”

This study characterized a new human keratin, hK6irs1, specifically found in the inner root sheath of hair follicles, which suggests its role in the structural integrity and guidance of growing hair shafts.

research The Catalog of Human Hair Keratins

272 citations , September 2001 in “Journal of Biological Chemistry”

This study cataloged human type II hair keratins, detailing their expression and differentiation roles in hair follicles and comparing them with type I keratins to explore keratin-pairing principles.

research Genes for Intermediate Filament Proteins and the Draft Sequence of the Human Genome

287 citations , July 2001 in “Journal of Cell Science”

This study mapped 65 intermediate filament genes in the human genome, highlighting that the majority of keratin-related sequences are inactive pseudogenes, notably for keratins 8 and 18.

research A Novel Type II Cytokeratin, mK6irs, Is Expressed in the Huxley and Henle Layers of the Mouse Inner Root Sheath

45 citations , March 2001 in “Journal of Investigative Dermatology”

This study identified a new cytokeratin, mK6irs, specifically expressed in the inner root sheath of mouse hair follicles, distinguishing it as a member of the type II cytokeratin family.

research A Unique Type I Keratin Intermediate Filament Gene Family Is Abundantly Expressed in the Inner Root Sheaths of Sheep and Human Hair Follicles

41 citations , January 2001 in “Journal of Investigative Dermatology”

research Characterization of a 300 Kbp Region of Human DNA Containing the Type II Hair Keratin Gene Domain

77 citations , March 2000 in “Journal of Investigative Dermatology”

The research identified six functional hair keratin genes and four pseudogenes, providing insights into hair formation and gene organization.

research The Catalog of Human Hair Keratins

235 citations , July 1999 in “Journal of biological chemistry/The Journal of biological chemistry”

This study establishes a catalog of human type I hair keratins and identifies their specific roles and expression patterns during hair differentiation and growth in scalp follicles.

research A Novel Human Type II Cytokeratin, K6hf, Specifically Expressed in the Companion Layer of the Hair Follicle

139 citations , December 1998 in “The journal of investigative dermatology/Journal of investigative dermatology”

This study identified a new type II cytokeratin, named K6hf, exclusively expressed in the companion layer of the human hair follicle, distinguishing it from other keratins and suggesting a unique biochemical role.

research Characterization of a 190-Kilobase Pair Domain of Human Type I Hair Keratin Genes

74 citations , October 1998 in “Journal of biological chemistry/The Journal of biological chemistry”

This study discovered nine human type I hair keratin genes, including a transcribed pseudogene, in a 190 kbp genomic region, revealing three gene subclusters based on sequence homologies.

research A Novel Monoclonal Antibody to the Outer Root Sheath Cells

3 citations , October 1994 in “Journal of Dermatological Science”

This study developed a novel monoclonal antibody, TYHF-1, which specifically reacts with hair keratins but not with epidermal keratins or various other tissue cells.

research Human Hair Keratins

38 citations , July 1993 in “Journal of Investigative Dermatology”

research Human Hair Keratins

90 citations , July 1993 in “Journal of Investigative Dermatology”

research Experimental Modulation of the Differentiated Phenotype of Keratinocytes from Epidermis and Hair Follicle Outer Root Sheath and Matrix Cells

31 citations , December 1991 in “Annals of the New York Academy of Sciences”

This study found that distinct keratin profiles enabled the evaluation of epithelial differentiation in human hair follicles, with mesenchymal cells playing a critical role in epidermoid differentiation of follicular cells.

research Keratins 1 and 10 as Regular Constituents of Inner Root Sheath and Cuticle Cells in the Human Hair Follicle

44 citations , August 1990 in “PubMed”

This study provides evidence for K1 and K10 derivatives' presence in the inner root sheath and hair cuticle, suggesting that these hair follicle parts may follow familiar keratinization principles.

research A New Look Into an Old Problem: Keratins as Tools to Investigate Determination, Morphogenesis, and Differentiation in Skin

156 citations , January 1989 in “Genes & Development”

This study found that keratin K14 expression occurs early in epidermal cell differentiation, while a hair-specific keratin is expressed later in hair matrix cells, suggesting developmental divergence between the two cell types.

research Patterns of Expression of Trichocytic and Epithelial Cytokeratins in Mammalian Tissues

124 citations , December 1988 in “Differentiation”

This study found that T cytokeratins appear more gradually and with complex coexpression patterns in developing nail structures compared to the more abrupt transition in hair follicles.

research Patterns of Expression of Trichocytic and Epithelial Cytokeratins in Mammalian Tissues II: Concomitant and Mutually Exclusive Synthesis of Trichocytic and Epithelial Cytokeratins in Diverse Human and Bovine Tissues (Hair Follicle, Nail Bed and Matrix, Lingual Papilla, Thymic Reticulum)

187 citations , May 1988 in “Differentiation”

This study found that trichocytic cytokeratins, typically found in hair, are also present in nails, filiform papillae of the tongue, and the epithelial reticulum of the thymus.

research Patterns of Expression of Trichocytic and Epithelial Cytokeratins in Mammalian Tissues: Human and Bovine Hair Follicles

248 citations , April 1988 in “Differentiation”

In this study, researchers observed that trichocytic and epithelial cytokeratins have distinct expression patterns within various human and bovine hair follicle cells, contributing to understanding hair follicle development and growth.

research Keratins of the Human Hair Follicle: Hyperproliferative Keratins Consistently Expressed in Outer Root Sheath Cells In Vivo and In Vitro

135 citations , November 1987 in “Differentiation”

This study found that cultured outer root sheath cells from human hair follicles expressed a keratin profile similar to their in vivo environment, indicating environmental influence on keratin expression.

Acidic and Basic Hair/Nail (Hard) Keratins: Their Colocalization in Upper Cortical and Cuticle Cells of the Human Hair Follicle and Their Relationship to Soft Keratins

research Acidic and Basic Hair/Nail (Hard) Keratins: Their Colocalization in Upper Cortical and Cuticle Cells of the Human Hair Follicle and Their Relationship to Soft Keratins

356 citations , December 1986 in “The journal of cell biology/The Journal of cell biology”

This study found that specific human hair keratins are differentially expressed in the hair follicle, suggesting a shared pathway of epithelial differentiation between hair cortex and nail plate cells.

research Cell Differentiation in Human Anagen Hair and Hair Follicles Studied with Anti-Hair Keratin Monoclonal Antibodies

81 citations , May 1986 in “Journal of Investigative Dermatology”

research Immunohistochemical Staining Characteristics of Epidermal Appendages: Hair Follicles and Eccrine Sweat Glands to Anti-Epidermal Keratin Antisera

6 citations , November 1984 in “Acta Dermato Venereologica”

This study investigated the immunohistochemical characteristics of keratin proteins in epidermal appendages, finding variable staining patterns in different skin structures and tumor cells, which suggests differences in keratinization.