The Keratins of the Human Beard Hair Medulla: The Riddle in the Middle

This review summarizes the cell type distribution and functional significance of human keratins, emphasizing their roles in tumor diagnosis and potential clinical applications, and reports no new clinical findings.

Keratin heterodimers are preferred for their specific and structural advantages.

K39 and K40 are the last keratins expressed in hair development, completing the hair keratin catalog.

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.

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

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.

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.

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

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.

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.

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.

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.

This study reports that expressed mouse type Ia and type IIa trichocyte keratins were successfully assembled into intermediate filaments in vitro, while also suggesting that disulfide bond cross linking enhances their stability.

Keratin 17 is important for hair and nail structure and affects pachyonychia congenita symptoms.

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.

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.

Androgens can cause hair growth in some areas and hair loss on the scalp.

This study identified a new 65 kD and 48 kD keratin pair expressed in specific mouse epithelial sites, suggesting a unique evolutionary branch of hair-related keratins.

Hoxc13 is important for hair and tongue development by controlling hair keratin genes.

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.

This study characterized proteins in hair-follicle and hair tissue, identifying similar protein types but with notable quantitative differences, which may reveal aspects of keratin protein synthesis.