The protein kinase CK2 phosphorylates SNAP190 to negatively regulate SNAPc DNA binding and human U6 transcription by RNA polymerase III
The protein kinase CK2 phosphorylates SNAP190 to negatively regulate SNAPc DNA binding and human U6 transcription by RNA polymerase III
复制标题
DOI：
10.1074/jbc.m702269200
复制
发表时间：
2007-09-21
影响因子：
4.8
通讯作者：
Henry, R. William
中科院分区：
文献类型：
--
作者：
Gu, Liping;Husain-Ponnampalam, Rhonda;Henry, R. William
通过RNA聚合酶III进行的人U6小核RNA基因转录需要通用转录因子SNAP（C），其与人小核RNA核心启动子元件结合并使与Brf 2-TFIIIB复合物的预起始复合物组装成核。该途径中的多个组分被蛋白激酶CK 2磷酸化，包括Brf 2-TFIIIB复合物的Bdp 1亚基和RNA聚合酶III，分别对U6转录产生阴性和阳性结果。然而，CK 2磷酸化SNAPC在U6转录中的作用尚未确定。在这份报告中，我们研究了CK 2在调节SNAPC转录特性中的作用，并证明在SNAP（C）中，CK 2磷酸化SNAP 190亚基的N-末端一半的两个区域（氨基酸20 - 63和514-545），每个区域都含有多个CK 2。共识网站CK 2对SNAP 190的磷酸化抑制了SNAPC DNA结合和U6转录活性。SNAP 190的突变分析支持其中CK 2磷酸化触发变构抑制的模型。SNAP 190 Myb DNA结合域的序列。
Human U6 small nuclear RNA gene transcription by RNA polymerase III requires the general transcription factor SNAP(C), which binds to human small nuclear RNA core promoter elements and nucleates pre-initiation complex assembly with the Brf2-TFIIIB complex. Multiple components in this pathway are phosphorylated by the protein kinase CK2, including the Bdp1 subunit of the Brf2-TFIIIB complex, and RNA polymerase III, with negative and positive outcomes for U6 transcription, respectively. However, a role for CK2 phosphorylation of SNAPC in U6 transcription has not been defined. In this report, we investigated the role of CK2 in modulating the transcriptional properties of SNAPC and demonstrate that within SNAP(C), CK2 phosphorylates the N-terminal half of the SNAP190 subunit at two regions (amino acids 20 - 63 and 514-545) that each contain multiple CK2. consensus sites. SNAP190 phosphorylation by CK2 inhibits both SNAPC DNA binding and U6 transcription activity. Mutational analyses of SNAP190 support a model wherein CK2 phosphorylation triggers an allosteric inhibition. of the SNAP190 Myb DNA binding domain.