NF-kappaB subunit p65 binds to 53BP2 and inhibits cell death induced by 53BP2.
Nuclear factor kappaB (NF-kappaB) is a transcription factor that controls the expression of many cellular and viral genes. The p65 (RelA) subunit plays a critical role as a transcriptional activator and recent observations have highlighted its role in the control of apoptosis. Here we report that 53BP2, a protein previously identified by interaction with wild type p53 and Bcl-2, also binds to p65 in a yeast two-hybrid system. This specific interaction was confirmed by pull-down assay in vitro and by a mammalian two-hybrid assay in vivo. We observed that full-length 53BP2 fused to GFP had a punctate distribution in cytoplasm, predominantly in perinuclear region whereas the N-terminal 53BP2 localized in cytoplasm and C-terminal 53BP2 localized in the nucleus. Furthermore, we found that overexpression of GFP-53BP2 induced apoptosis in transiently transfected cells. Neither the N-terminal nor the C-terminal of 53BP2 fused to GFP induced cell death. Interestingly, co-transfection with a p65 expression plasmid significantly inhibited 53BP2-induced cell death. The previous findings that 53BP2 bound to p53 and Bcl-2 together with our present observations suggest that 53BP2 may play a central role in the regulation of apoptosis and cell growth.
Yang
J P
JP
Department of Molecular Genetics, Nagoya City University Medical School, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
Hori
M
M
Takahashi
N
N
Kawabe
T
T
Kato
H
H
Okamoto
T
T
D000818:Animals; D017487:Ankyrins / Q000737:chemistry; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins; D019556:COS Cells; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D002453:Cell Cycle; D002461:Cell Line, Transformed; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism / Q000502:physiology*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D012441:Saccharomyces cerevisiae; D051996:Transcription Factor RelA; D018909:src Homology Domains
D017487:Ankyrins; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; D016328:NF-kappa B; D011993:Recombinant Fusion Proteins; C090468:TP53BP2 protein, human; D051996:Transcription Factor RelA