Krtap11-1, a hair keratin-associated protein, as a possible crucial element for the physical properties of hair shafts.
BACKGROUND
The physical properties of the hair are predominantly determined by the assembly of keratin bundles. The keratin-associated proteins (Krtaps) are thought to be involved in keratin bundle assembly, however, the functional role of the individual member still remains largely unknown.


OBJECTIVE
The aim of this study is to clarify the role of a unique class of Krtaps, Krtap11-1, in the development and physical properties of the hair.


METHODS
The expression regulation of Krtap11-1 was analyzed and its binding partners in the hair cortex were determined. Also, the effects of the forcible expression of this protein on the hair follicle development were analyzed in culture.


RESULTS
The expression pattern of Krtap11-1 was concentrically asymmetric in the faulty hair that develops in Foxn1nu mice. In cultured keratinocytes, the expression of Krtap11-1 transgene product was strictly regulated by the keratinization process and proteasome-dependent protein elimination. While the association with keratin as well as the cohesive self-assembly of Krtap11-1 appeared to be stabilized by disulfide cross-links, the biotinylated Krtap11-1 probe enabled the adherence to certain type I keratins in the hair cortex, including K31, 33 and 34, in the absence of disulfide formation. When embryonic upper lip rudiments were forcibly introduced with Krtap11-1, the hair follicles formed irregularly arranged globular hair keratin-clumps surrounded by multilayered epithelial cells in culture.


CONCLUSIONS
Krtap11-1 may play an important role on keratin-bundle assembly in the hair cortex and this study provides insight into the physical properties of the hair shaft.
Department of Bioscience, Graduate School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan.
Shunsuke
S
Fujimoto
Department of Bioscience, Graduate School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan.
Takahisa
T
Takase
Department of Bioscience, Graduate School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan.
Nanako
N
Kadono
Department of Bioscience, Graduate School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan.
Kenji
K
Maekubo
Department of Bioscience, Graduate School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan. Electronic address: y-hirai@kwansei.ac.jp.
Yohei
Y
Hirai
D000595:Amino Acid Sequence; D000818:Animals; D019921:Biotinylation; D045744:Cell Line, Tumor; D004220:Disulfides / Q000737:chemistry; D005347:Fibroblasts / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006197:Hair / Q000378:metabolism*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology; D053564:Keratins, Hair-Specific / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019076:Transgenes
D004220:Disulfides; D053564:Keratins, Hair-Specific; D011994:Recombinant Proteins; D046988:Proteasome Endopeptidase Complex
Hacl-1; IF assembly; KAPs; Keratin; Krtap