Upregulation of class II beta-tubulin expression in differentiating keratinocytes.
The diverse functions of microtubules (MT) in different cells and tissues may be facilitated by compositional changes in tubulin isotypes. We obtained partial cDNA clones of class II beta-tubulin from a library of differentiating normal human epidermal keratinocytes (NHEK) cells, whereas screening via subtractive hybridization for genes involved in calcium-induced keratinocyte differentiation. Analysis of the isotypic composition of beta-tubulin from NHEK cells revealed elevations in class II beta-tubulin concentrations at both protein and message levels during cell differentiation, resulting in increased rates of incorporation of class II beta-tubulin into MT. Immunohistochemistry of normal and pathologic skin tissues showed that class II beta-tubulin occurred in the granular layer of the epidermis and in differentiated areas of carcinomas. Class II beta-tubulin was, however, not observed in the uppermost granular and cornified layers of normal epidermis. Further experiments showed that MT were likely to decay in the final stage of terminal differentiation during formation of the cornified envelope. Our results suggest that there is differential modulation of MT composition and stability during keratinocyte differentiation.
Lee
Woong-Hee
WH
Department of Dermatology, School of Medicine, Chungnam National University, Deajeon, Korea.
Kim
Joo-Young
JY
Kim
Young-Sik
YS
Song
Hye-Joon
HJ
Song
Ki-Joon
KJ
Song
Jin-Won
JW
Baek
Luck-Ju
LJ
Seo
Eun-Young
EY
Kim
Chang Deok
CD
Kim
Chang-Duk
CD
Lee
Jeung-Hoon
JH
Kee
Sun-Ho
SH
D000107:Acetylation; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D015603:Keratinocytes / Q000166:cytology* / Q000502:physiology*; D008870:Microtubules / Q000502:physiology; D012867:Skin / Q000166:cytology / Q000378:metabolism; D014404:Tubulin / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology
D014404:Tubulin