p160/SRC/NCoA coactivators form complexes via specific interaction of their PAS-B domain with the CID/AD1 domain
p160/SRC/NCoA coactivators form complexes via specific interaction of their PAS-B domain with the CID/AD1 domain
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DOI：
10.1093/nar/gkn029
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发表时间：
2008-04-01
影响因子：
14.9
通讯作者：
Pfitzner, Edith
中科院分区：
文献类型：
--
作者：
Lodrini, Marco;Muenz, Tobias;Pfitzner, Edith
转录激活涉及通过不同的结合结构域和识别基序之间的直接相互作用来有序地募集共激活因子。p160/SRC/NCoA共激活因子家族包括三个成员（NCoA-1、-2和-3），它们被组织成多蛋白共激活因子复合物。我们已经鉴定了NCoA-1的PAS-B结构域为LXXLL基序结合结构域。在这里，我们表明，NCoA家族成员能够通过其PAS-B结构域与其他全长NCoA蛋白相互作用，并且它们特异性地与NCoA-1的CBP相互作用结构域（CID/AD 1）相互作用。LXXLL基序的肽竞争、结合实验和诱变指向NCoA PAS-B结构域的不同结合基序特异性。不同NCoA-1-PAS-B/LXXLL肽复合物的NMR研究揭示了CID/AD 1和STAT 6反式激活结构域LXXLL基序的相似但不相同的结合位点。在机制研究中，我们发现PAS-B结构域的过表达能够干扰细胞中NCoA-1与CBP的结合，并且CID/AD 1肽在体外与STAT 6竞争NCoA-1。此外，内源性雄激素受体靶基因的表达受到NCoA-1或NCoA-3 PAS-B结构域的过表达的影响。我们的研究揭示了一个新的，互补的机制，目前的模式，辅激活剂招聘靶基因启动子。
Transcriptional activation involves the ordered recruitment of coactivators via direct interactions between distinct binding domains and recognition motifs. The p160/SRC/NCoA coactivator family comprises three members (NCoA-1, -2 and -3), which are organized in multiprotein coactivator complexes. We had identified the PAS-B domain of NCoA-1 as an LXXLL motif binding domain. Here we show that NCoA family members are able to interact with other full-length NCoA proteins via their PAS-B domain and they specifically interact with the CBP-interaction domain (CID/AD1) of NCoA-1. Peptide competition, binding experiments and mutagenesis of LXXLL motifs point at distinct binding motif specificities of the NCoA PAS-B domains. NMR studies of different NCoA-1-PAS-B/LXXLL peptide complexes revealed similar although not identical binding sites for the CID/AD1 and STAT6 transactivation domain LXXLL motifs. In mechanistic studies, we found that overexpression of the PAS-B domain is able to disturb the binding of NCoA-1 to CBP in cells and that a CID/AD1 peptide competes with STAT6 for NCoA-1 in vitro. Moreover, the expression of an endogenous androgen receptor target gene is affected by the overexpression of the NCoA-1 or NCoA-3 PAS-B domains. Our study discloses a new, complementary mechanism for the current model of coactivator recruitment to target gene promoters.