51. Casper/c-FLIP is physically and functionally associated with NF-κB1 p105
- Author
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Li, Zhiqin, Zhang, Jingbo, Chen, Danying, and Shu, Hong-Bing
- Subjects
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APOPTOSIS , *GENETIC regulation , *TRANSCRIPTION factors , *NF-kappa B - Abstract
Casper/c-FLIP is a caspase-8-related molecule critically involved in regulation of death receptor-induced apoptosis. It has been shown that Casper can either promote or antagonize apoptosis and can activate the transcription factor NF-κB. The exact functions of Casper are controversial. To further understand how Casper signals, we searched Casper-interacting proteins by yeast two-hybrid screening. This effort identified NF-κB1 (p105), an atypical IκB molecule and the precursor of NF-κB subunit p50. Co-immunoprecipitation experiments indicated that Casper interacted with p105 in 293 cells and this interaction was mediated through the C-terminal IκB-like domain (IκBγ). Overexpression of p105 and IκBγ inhibited Casper-induced NF-κB activation and potentiated Casper-induced apoptosis. Furthermore, Casper and its C-terminal caspase-like domain inhibited p105 processing into p50. Our findings suggest that p105 is involved in Casper-mediated regulation of apoptosis and NF-κB activation. [Copyright &y& Elsevier]
- Published
- 2003
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