Abstract
A sensitive DNA-protein crosslinking approach has been used to characterize four inducible T-cell proteins (50 kDa, 55 kDa, 75 kDa, and 85 kDa) that specifically bind to κB enhancer elements. Partial proteolytic mapping revealed a distinct cleavage pattern for three of these proteins. These polypeptides are sequestered as inactive precursors in the cytosol of unstimulated T cells but can be converted into active forms in vivo by phorbol ester stimulation or in vitro by detergent treatment. The induction of these proteins by phorbol ester results in a strikingly biphasic pattern of nuclear expression with the 55-kDa and 75-kDa species appearing within minutes, whereas the 50-kDa and 85-kDa species appear only several hours after cellular stimulation. These data suggest that NF-κB-binding activity may not correspond to a single polypeptide but rather a family of at least four inducible and differentially regulated DNA-binding proteins that are expressed with distinct kinetics in human T lymphocytes.
Original language | English (US) |
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Pages (from-to) | 10028-10032 |
Number of pages | 5 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 87 |
Issue number | 24 |
State | Published - 1990 |
Keywords
- Cytoplasmic inhibitor IκB
- DNA-protein crosslinking
- Human immunodeficiency virus
- Interleukin 2 receptor
- T-cell activation