Combinatoial CREB/ATF dimers and cellular growth control

申请人描述：ATF/CREB/AP-1家族的蛋白质是 监控细胞内和细胞外的信号转导通路 并将这些信号传输到下游目标。一些家庭 成员(如VFO和VJUN)是致癌的。ATF/CREB/AP-1蛋白共有一个 保守的bZIP结构域，介导蛋白质二聚和 序列特异性DNA结合活性。而bZIP域名高度依赖于 BZIP蛋白的一些组合彼此同源，形成二聚体， 而其他人则不这么认为。此外，不同的bZIP二聚体具有显著的 区分密切相关的DNA结合位点的能力。这将使 一组有限的bZIP单体，以形成一系列杂二聚体，每个 它可能调节了一组特定的基因的表达 在特定的生物反应中。了解哪种bZIP蛋白 二聚体可以形成，它们占据什么DNA位点，以及这些事件是如何被调控的 将揭示控制细胞动态平衡和/或 差异化。裂解酵母S.pombe提供了一个诱人的模式 生物体进行这样的研究。我们已经证明了裂解酵母的bZIP蛋白 在体内和体外形成组合二聚体。各种二聚体都在 MAP激酶级联反应的调控和不同二聚体诱导的不同效应 功能。因为S.pombe的基因组很小(大约6000个基因)，而 测序项目即将完成，人们可以识别和分析 大多数细胞内的bZIP蛋白。由于缺乏bZIP蛋白的突变体和 信号转导蛋白一般都是可行的，也有可能 揭示上游调控和下游效应器功能。一个 裂解酵母bZIP蛋白二聚体的全面系统分析 是提议的。目的1，阐明S.pombe的bZIP字母表：确定 BZIP二聚体的成对组合关联和识别DNA位点 它们以很高的亲和力结合在一起。目的2，揭示人类免疫缺陷的分子决定因素 组合二聚体形成和DNA结合：比较高分辨率 BZIP二聚体单独的结构和与其DNA位点的络合。目标3，至 进一步表征压力反应的调节机制，由 Mts1 bZIP蛋白：阐明MAP激酶SpCL在控制AN中的作用 Mts1的自身抑制功能。

APPLICANT'S DESCRIPTION: Proteins of the ATF/CREB/AP-1 family are components of signal transduction pathways that monitor intracellular and extracellular conditions and transmit those signals to downstream targets. Some family members (e.g., vFos and vJun) are oncogenic. ATF/CREB/AP-1 proteins share a conserved bZIP domain that mediates both protein dimerization and sequence-specific DNA binding activity. While the bZIP domains are highly homologous to one another, some combinations of bZIP proteins form dimers, while others do not. Furthermore, different bZIP dimers have the remarkable ability to discriminate between closely related DNA binding sites. This enables a limited set of bZIP monomers to form a repertoire of heterodimers, each of which presumably regulates the expression of a specific set of genes involved in a particular biological response. An understanding of which bZIP protein dimers can form, what DNA sites they occupy, and how such events are regulated will reveal fundamental aspects in the control of cellular homeostasis and/or differentiation. The fission yeast S. pombe provides an attractive model organism for such a study. We have shown that bZIP proteins of fission yeast form combinatorial dimers in vivo and in vitro. The various dimers are under control of a MAP kinase cascade and different dimers elicit distinct effector functions. Because S. pombe has a small genome (about 6,000 genes), and the sequencing project is nearly complete, one can identify and analyze the majority of cellular bZIP proteins. Since mutants lacking bZIP proteins and signal transduction proteins are generally viable, it is also possible to reveal both upstream regulatory and downstream effector functions. A comprehensive and systematic analysis of bZIP protein dimers of fission yeast is proposed. Aim 1, To elucidate the bZIP alphabet of S. pombe: determine pairwise combinatorial associations of bZIP dimers and identify DNA sites to which they bind with high affinity. Aim 2, To reveal molecular determinants of combinatorial dimer formation and DNA binding: compare high-resolution structures of bZIP dimers alone and complexed to their DNA sites. Aim 3, To further characterize regulatory mechanisms for stress responses mediated by the Mts1 bZIP protein: elucidate the role of the MAP kinase Spcl in controlling an autoinhibitory function of Mts1.