Stöven S, Ando I, Kadalayil L, Engström Y, Hultmark D
Umeå Center for Molecular Pathogenesis, Umeå University, Sweden.
EMBO Rep. 2000 Oct;1(4):347-52. doi: 10.1093/embo-reports/kvd072.
The Rel/NF-kappaB transcription factor Relish plays a key role in the humoral immune response in Drosophila. We now find that activation of this innate immune response is preceded by rapid proteolytic cleavage of Relish into two parts. An N-terminal fragment, containing the DNA-binding Rel homology domain, translocates to the nucleus where it binds to the promoter of the Cecropin A1 gene and probably to the promoters of other antimicrobial peptide genes. The C-terminal IkappaB-like fragment remains in the cytoplasm. This endoproteolytic cleavage does not involve the proteasome, requires the DREDD caspase, and is different from previously described mechanisms for Rel factor activation.
Rel/NF-κB转录因子Relish在果蝇的体液免疫反应中起关键作用。我们现在发现，这种先天免疫反应的激活之前，Relish会迅速被蛋白水解切割成两部分。一个包含DNA结合Rel同源结构域的N端片段会转移到细胞核，在那里它与天蚕素A1基因的启动子结合，可能还与其他抗菌肽基因的启动子结合。C端类IkappaB片段则留在细胞质中。这种内蛋白水解切割不涉及蛋白酶体，需要DREDD半胱天冬酶，并且与先前描述的Rel因子激活机制不同。
