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Keratin attenuates tumor necrosis factor–induced cytotoxicity through association with TRADD
Keratin 8 and 18 (K8/18) are the major components of intermediate filament (IF) proteins of simple or single-layered epithelia. Recent data show that normal and malignant epithelial cells deficient in K8/18 are nearly 100 times more sensitive to tumor necrosis factor (TNF)–induced cell death. We hav...
Autores principales: | , , , , , , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
2001
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150850/ https://www.ncbi.nlm.nih.gov/pubmed/11684708 http://dx.doi.org/10.1083/jcb.200103078 |
Sumario: | Keratin 8 and 18 (K8/18) are the major components of intermediate filament (IF) proteins of simple or single-layered epithelia. Recent data show that normal and malignant epithelial cells deficient in K8/18 are nearly 100 times more sensitive to tumor necrosis factor (TNF)–induced cell death. We have now identified human TNF receptor type 1 (TNFR1)–associated death domain protein (TRADD) to be the K18-interacting protein. Among IF proteins tested in two-hybrid systems, TRADD specifically bound K18 and K14, type I (acidic) keratins. The COOH-terminal region of TRADD interacted with the coil Ia of the rod domain of K18. Endogenous TRADD coimmunoprecipitated with K18, and colocalized with K8/18 filaments in human mammary epithelial cells. Overexpression of the NH(2) terminus (amino acids 1–270) of K18 containing the TRADD-binding domain as well as overexpression of K8/18 in SW13 cells, which are devoid of keratins, rendered the cells more resistant to killing by TNF. We also showed that overexpressed NH(2) termini of K18 and K8/18 were associated with endogenous TRADD in SW13 cells, resulting in the inhibition of caspase-8 activation. These results indicate that K18 may sequester TRADD to attenuate interactions between TRADD and activated TNFR1 and moderate TNF-induced apoptosis in simple epithelial cells. |
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