FUNCTIONAL STUDIES OF BRASSINOSTEROID-REGULATED PROTEINS

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 油菜素类固醇(BRs)是一类植物类固醇激素，在细胞扩张、细胞分裂、维管分化、种子萌发、光形态建成、抗逆性和抗病等生理发育过程中发挥重要作用。分子遗传学研究已经确定了BR信号通路中的几个BR信号转导成分，BRs通过与细胞表面受体结合来调节核基因的表达。然而，目前的BR信号通路仍存在空白。特别是，将BR信号从质膜转导到细胞质成分的受体激酶的底物尚不清楚。尽管基因研究取得了成功，但许多基因的功能无法通过正向遗传方法来发现，这主要是由于遗传冗余。因此，需要其他方法来显著提高我们对BR信号通路的理解。因此，我们进行了蛋白质组学研究，并利用双向差示凝胶电泳(2-D DGE)和质谱仪鉴定了拟南芥中BR调节的蛋白质。本研究旨在研究定位于质膜上的BR反应蛋白，包括BR信号转导蛋白(BSK)。对这些蛋白的功能研究表明，它们作为BRI1底物在BR信号通路中起着关键作用。我们计划通过亲和纯化和质谱分析来鉴定更多的BSK相互作用蛋白。这样的分析将加深我们对BR信号转导的理解，并为提高植物生产力提供分子工具。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Brassinosteroids (BRs) are plant steroid hormones, which play important roles in a wide range of physiological and developmental processes, including cell expansion, cell division, vascular differentiation, seed germination, photomorphogenesis, stress tolerance and disease resistance. Molecular genetic studies have identified several BR signal transduction components of the BR signaling pathway, through which BRs bind the cell surface receptors to regulate nuclear gene expression. However, there are still gaps in the current BR signaling pathway. In particular, the substrates of the receptor kinases that transduce the BR signal from plasma membrane to cytoplasmic components remain unknown. Despite the success of genetic studies, many genes' function cannot be discovered by forward genetic approaches, largely due to genetic redundancy. Therefore, alternative approaches are required to significantly advance our understanding of the BR signaling pathway. Thus, we have performed proteomic studies and identified BR-regulated proteins in Arabidopsis using two-dimensional difference gel electrophoresis (2-D DIGE) followed by mass spectrometry. This study aims at characterizing plasma membrane-localized BR-responsive proteins, including the BR-signaling kinases (BSKs). Functional studies of these proteins have demonstrated their key role as BRI1 substrate in the BR signaling pathway. We plan to identify additional interacting proteins of BSKs using affinity purification followed by mass spectrometry analysis. Such analysis will advance our understanding of BR signal transduction and provide molecular tools for improving plant productivity.