STRUCTURE/FUNCTION OF PITSLRE KINASES

PITSLRE蛋白激酶是CDK，包括20多种 不同的同种型，并且普遍表达。很少有人知道他们 功能PITSLRE p110激酶亚型定位于核质， 核斑点，由染色质内颗粒簇（IGCs）组成的区域， 其是转录/RNA加工因子的储存和组装位点。 申请人发现PITSLRE p110激酶直接与RNPS 1相互作用， 一种通用RNA剪接因子，和EKK 2，一种转录延伸因子， 在体外和体内。PITSLRE p110也与RNAPII和CKII相关， vivo. CKII磷酸化不完全重复序列的一个非常特定的部分， RNAPII CTD区域以及氨基末端的特定区域 PITSLRE p110的结构域。目前的提案将解决 假设PITSLRE p110激酶调节转录、RNA加工或 并且其与CKII的关联在这些功能中发挥作用，和/或 这种激酶在细胞核内的定位。PITSLRE p110复合物将 从核质和IGC中进行生物化学纯化和表征。 它的底物和监管机构将被确定。申请人将决定 如果CKII在体内磷酸化PITSLRE p110和CTD， 磷酸化的生物学后果。最后，各方面的作用 将通过敲除小鼠中的基因来检查PITSLRE激酶亚型。

The PITSLRE protein kinases are CDKs that include more than 20 different isoforms and are ubiquitously expressed. Little is known about their function. The PITSLRE p110 kinase isoforms are localized to the nucleoplasm and nuclear speckles, regions composed of intrachromatin granule clusters (IGCs), which are storage and assembly sites for transcription/RNA processing factors. The applicant has found that PITSLRE p110 kinase interacts directly with RNPS1, a general RNA splicing factor, and EKK2, a transcriptional elongation factor, in vitro and in vivo. PITSLRE p110 also associates with RNAPII and CKII in vivo. CKII phosphorylates a very specific portion of the imperfect repeat region of the RNAPII CTD as well as a specific region of the amino terminal domain of PITSLRE p110 in vitro. The current proposal will address the hypothesis that PITSLRE p110 kinases regulate transcription, RNA processing, or both and that its association with CKII plays a role in these functions an/or the localization of this kinase within the nucleus. PITSLRE p110 complexes will be biochemically purified and characterized from the nucleoplasm and the IGC. Its substrates and regulators will be identified. The applicant will determine if CKII phosphorylates PITSLRE p110 and the CTD in vivo and also assess the biological consequences of the phosphorylation. Finally the role of the various PITSLRE kinase isoforms will be examined by knocking-out the genes in mice.