CA2+-Mediated Signal Transduction in Plants

最近发现了一个新的钙依赖蛋白激酶家族，称为CDPKs。CDPKs是独一无二的，因为它们具有一种新的结构，其激活域与类似于钙调蛋白的钙结合域相连。一个重要的长期目标是了解CDPKs在钙离子介导的信号转导通路中的功能。为此目的选择了模式植物系统拟南芥。该提案的基础是确定钙离子如何调节CDPK活性。生物化学和分子遗传学方法将被用于测试一种被称为“流水线版本的CaMK II”的模型。一种大肠杆菌。为此目的提供功能性酶的表达系统已经被开发出来。将采用两种方法来研究特定的CDPK亚型的生物学功能：1)在转基因植物中过表达亚型AK1和突变型AK1，以检测改变其体内活性平衡的效果。2)确定AK1‘S的胞内定位，以提供其体内潜在底物的信息。

A new family of Ca2+-dependent protein kinases, called CDPKs, has recently been discovered. CDPKs are unique because they have a novel structure with a kinase domain joined to a Ca2+-binding domain similar to calmodulin. An important long term goal is to understand the function of CDPKs in Ca2+-mediated signal transduction pathways. The model plant system Arabidopsis has been chosen for this purpose. The foundation of the proposal is to determine how Ca2+ regulates CDPK activity. A biochemical and molecular genetic approach will be used to test a model referred to as a "stream-lined version of CaMK II". An E. coli. expression system has been developed to provide functional enzyme for this purpose. Two approaches will be pursued to investigate the biological functions of a specific CDPK isoform: 1) Isoform AK1 and a mutant "unregulated" version of AK1, will be over-expressed in transgenic plants to examine the effects of altering the balance of its activity in vivo. 2) AK1's intracellular location will be determined to provide information on its potential in vivo substrates.