The major structural proteins in epithelial cells are keratins, which occur as part of an intermediate filament (IF) scaffold in their cytoplasm. The IF scaffold provides a mechanical resilience that is vital to epithelial cells in the face of mechanical trauma, and accordingly mutations in keratin genes underlie many inherited epithelial fragility syndromes. Two Types of keratin proteins, I and II, are encoded by >40 genes in mammalian genomes. This dual character reflects a strict requirement for co-assembly, and underlies the co-regulation of Type I and Type II genes by epithelial cells. The observed pairwise and differentiation-specific expression of most Type I and type II keratin genes suggests a role for these proteins in promoting aspects of the cytoarchitecture and function of epithelial cells. This project will study two Type I keratins, K16 and K17. These keratins are of interest to us because of their regulation during development, their distribution in mature skin appendages (hair, nail, glands), and their induction in wound edge tissue after skin injury and in the context of skin diseases (psoriasis, carcinoma). The application posits that expression of K16 and K17 promotes a plastic cytoarchitecture enabling keratinocytes to migrate and differentiate along multiple pathways. To define the specific function(s) of K16 and K17, there are plans to characterize mouse strains carrying null mutations in the corresponding genes. The applicants recently reported that targeted expression of K16 can only partially compensate for the skin blistering phenotype produced by a null mutation in the K14 gene, a related Type I keratin. They also showed that the functional differences between K14 and K16 are encoded in their carboxy-terminal portion, and that the latter contributes to the cytoplasmic organization and mechanical properties of Ifs. There are also plans to characterize the mechanical properties of the three major types of keratin co-polymers found in the soft epithelia of the skin: K5-K14, Kl-K10, and K6-K161K17. Through mutagenesis studies will be used to define the biochemical basis for these properties, and their regulation. These studies will help us understand the role(s) of keratin proteins in the skin.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR044232-07
Application #
6511878
Study Section
Special Emphasis Panel (ZRG1-SSS-G (04))
Program Officer
Moshell, Alan N
Project Start
1996-09-20
Project End
2005-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
7
Fiscal Year
2002
Total Cost
$396,488
Indirect Cost
Name
Johns Hopkins University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Jacob, Justin T; Coulombe, Pierre A; Kwan, Raymond et al. (2018) Types I and II Keratin Intermediate Filaments. Cold Spring Harb Perspect Biol 10:
Wang, Fengrong; Chen, Song; Liu, Hans B et al. (2018) Keratin 6 regulates collective keratinocyte migration by altering cell-cell and cell-matrix adhesion. J Cell Biol 217:4314-4330
Zieman, Abigail; Coulombe, Pierre A (2018) The keratin 16 null phenotype is modestly impacted by genetic strain background in mice. Exp Dermatol 27:672-674
Kerns, Michelle L; Hakim, Jill M C; Zieman, Abigail et al. (2018) Sexual Dimorphism in Response to an NRF2 Inducer in a Model for Pachyonychia Congenita. J Invest Dermatol 138:1094-1100
Coulombe, Pierre A (2017) The Molecular Revolution in Cutaneous Biology: Keratin Genes and their Associated Disease: Diversity, Opportunities, and Challenges. J Invest Dermatol 137:e67-e71
Hobbs, Ryan P; Jacob, Justin T; Coulombe, Pierre A (2016) Keratins Are Going Nuclear. Dev Cell 38:227-33
Hobbs, R P; Batazzi, A S; Han, M C et al. (2016) Loss of Keratin 17 induces tissue-specific cytokine polarization and cellular differentiation in HPV16-driven cervical tumorigenesis in vivo. Oncogene 35:5653-5662
Kerns, Michelle L; Hakim, Jill M C; Lu, Rosemary G et al. (2016) Oxidative stress and dysfunctional NRF2 underlie pachyonychia congenita phenotypes. J Clin Invest 126:2356-66
Wang, Fengrong; Zieman, Abigail; Coulombe, Pierre A (2016) Skin Keratins. Methods Enzymol 568:303-50
Hobbs, Ryan P; DePianto, Daryle J; Jacob, Justin T et al. (2015) Keratin-dependent regulation of Aire and gene expression in skin tumor keratinocytes. Nat Genet 47:933-8

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