Recruitment of CREB binding protein is sufficient for CREB-mediated gene activation
Recruitment of CREB binding protein is sufficient for CREB-mediated gene activation
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DOI：
10.1128/mcb.20.5.1546-1552.2000
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发表时间：
2000-03-01
影响因子：
5.3
通讯作者：
Goodman, RH
中科院分区：
文献类型：
--
作者：
Cardinaux, JR;Notis, JC;Goodman, RH
转录因子CREB的磷酸化导致共激活因子CREB结合蛋白（CBP）的募集。最近的研究表明，CBP的募集不足以维持CREB的功能，然而，我们已经确定了CREB和另一种转录因子SREBP（sterol-responsive element binding protein）的CBP结合结构域中保守的蛋白质-蛋白质相互作用基序。与CREB相反，SREBP在没有磷酸化的情况下与CBP相互作用。我们利用这种相互作用基序的保守性来测试CBP向CREB的募集是否足以激活转录。从SREBP到CREB的激活结构域的六个非保守氨基酸的取代赋予高亲和力，磷酸化独立的CBP结合。突变的CREB分子，CREBDIEDML，激活转录在F9畸胎瘤和PC 12细胞，即使在蛋白激酶A（PKA）的情况下，添加外源性CBP增强的转录水平介导的CREBDIEDML，和腺病毒12 S E1 A阻断转录，涉及CBP在激活过程中。因此，CBP向CREB的募集足以激活转录。PKA的加入进一步刺激CREBDIEDML诱导的转录，表明CBP募集下游的磷酸化事件增强CREB信号传导。
Phosphorylation of the transcription factor CREB leads to the recruitment of the coactivator, CREB binding protein (CBP), Recent studies have suggested that CBP recruitment is not sufficient for CREB function, however, We have identified a conserved protein-protein interaction motif within the CBP-binding domains of CREB and another transcription factor, SREBP (sterol-responsive element binding protein). In contrast to CREB, SREBP interacts with CBP in the absence of phosphorylation, We have exploited the conservation of this interaction motif to test whether CBP recruitment to CREB is sufficient for transcriptional activation. Substitution of six nonconserved amino acids from SREBP into the activation domain of CREB confers high-affinity, phosphorylation-independent CBP binding. The mutated CREB molecule, CREBDIEDML, activates transcription in F9 teratocarcinoma and PC12 cells even in the absence of protein kinase A (PKA), Addition of exogenous CBP augments the level of transcription mediated by CREBDIEDML, and adenovirus 12S E1A blocks transcription, implicating CBP in the activation process. Thus, recruitment of CBP to CREB is sufficient for transcriptional activation, Addition of PKA stimulates transcription induced by CREBDIEDML further, suggesting that a phosphorylation event downstream from CBP recruitment augments CREB signaling.