TLDR Keratin 15 helps maintain tissue integrity and is reduced in activated keratinocytes.
The study investigated the expression of Keratin 15 (K15) in stratified epithelia, finding that K15 was primarily expressed in basal keratinocytes and absent in hair bulbs, but present in the outer root sheath of hair follicles. K15 expression increased when Keratin 14 (K14) was absent, suggesting a compensatory role. However, K15 was downregulated in activated keratinocytes, such as those in psoriasis and hypertrophic scars, indicating that K15 expression was not compatible with keratinocyte activation. The study concluded that K15 might play a crucial role in maintaining tissue integrity and could be involved in keratinocyte growth and differentiation, particularly in basal keratinocytes, which may include stem cell populations.
124 citations
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December 1988 in “Differentiation” Trichocytic differentiation starts in cells with epithelial cytokeratins, transitioning to trichocytic cytokeratins in hair and gradually in nails.
248 citations
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April 1988 in “Differentiation” Human and bovine hair follicles have distinct cytokeratins specific to hair-forming cells.
135 citations
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November 1987 in “Differentiation” Outer root sheath cells consistently express certain keratins influenced by their environment.
138 citations
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March 2007 in “Experimental cell research” Only a few hair-specific keratins are linked to inherited hair disorders.
276 citations
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January 2005 in “International review of cytology” More research is needed to understand how hair keratins work and their role in hair disorders.
199 citations
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January 2004 in “The International Journal of Developmental Biology” Hair follicle growth and development are controlled by specific genes and molecular signals.
29 citations
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April 2003 in “Experimental dermatology” Human hair follicles grown in vitro maintain normal keratin patterns and structure.
10 citations
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October 2000 in “PubMed” E6/E7 oncogenes in hair follicles cause continuous hair growth by skipping the resting phase.
94 citations
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February 1994 in “The journal of investigative dermatology/Journal of investigative dermatology” EGF makes hair follicles grow longer but stops hair production.
135 citations
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November 1987 in “Differentiation” Outer root sheath cells consistently express certain keratins influenced by their environment.