One clone contained a cDNA insert with almost the entire coding sequence (amino acid 44-335) of human CSN5/JAB1, which is a coactivator of AP-1 transcription and the subunit 5 of CSN.

• 其中,JAB1又属于COP9复合物的第五组分,负责调节植物中的光信号、线虫中的幼虫发育、整合素信号、细胞周期调控和甾体类激素信号传导。 并且,其功能主要是加强AP-1(c-Jun/c-fos)与AP-1结合位点(TRE)即AP-1启动子区的结合力与稳定性,从而增强AP-1反式转录活性。