Calcium Messenger System in Plants

有人提出钙在植物组织对激素（生长素和细胞分裂素）和光等信号的反应中起信使作用。普瓦雅博士研究的总体目标是了解钙离子在植物中的作用。最近的研究表明，在许多植物系统中存在钙依赖性和钙调素依赖性蛋白磷酸化。本研究下一个实验的重点将是钙和钙调素促进蛋白激酶及其底物，以期了解它们的生理作用。将追求两个目标：1。钙调节蛋白激酶及其底物将通过免疫细胞化学分离、表征和定位。2. 钙和钙调素依赖蛋白激酶的底物将被鉴定和表征，以便更深入地了解钙和钙调素依赖蛋白磷酸化的生理意义。激素、光和重力控制着植物整个生命周期的各种生理过程。细胞是如何感知这些信号并将其转化为反应的，人们对这一问题知之甚少，这也是一个非常有趣的问题。最近的研究支持这样一种观点，即植物中的一些激素和光依赖性变化涉及钙作为信使。拟议的研究旨在了解钙的这一功能。这些研究结果将促进我们对钙的细胞功能以及植物中激素和光信号转导的分子机制的认识。

It is proposed that calcium acts as a messenger in the response of plant tissues to signals such as hormones (auxin and cytokinin) and light. The overall objective of Dr. Poovaiah's research is to understand this role of calcium ions in plants. Recent studies have demonstrated the presence of calcium- dependent and calmodulin-dependent protein phosphorylation in a number of plant systems. The focus of the next experiments in this study will be calcium- and calmodulin-promoted protein kinases and their substrates, with a view toward understanding their physiological roles. Two goals will be pursued: 1. Calcium-regulated protein kinases and their substrates will be isolated, characterized, and localized by immunocytochemistry. 2. The substrates for calcium- and calmodulin-dependent protein kinases will be identified and characterized in order to obtain more insight into the physiological significance of calcium and calmodulin-dependent protein phosphorylation. Hormones, light, and gravity control diverse physiological processes throughout the life cycle of plants. How the cell senses these signals and converts them into a response is poorly understood and is a subject of great interest. Recent investigations support the concept that some hormone and light dependent changes in plants involve calcium as a messenger. The proposed research is directed toward understanding this function of calcium. The results of these studies will advance our knowledge of both the cellular functions of calcium and the molecular mechanisms involved in the transduction of hormone and light signals in plants.