Calcium Regulation of Cytokinin-Stimulated Morphogenesis in Plant Cells

植物细胞细胞分裂素刺激形态发生的钙调节

• 批准号: 8802011
• 负责人: Mary Jane Saunders
• 金额: $ 14万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-08-01 至 1992-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8802011&HistoricalAwards=false
• 关键词: Calcium; Regulation; Cytokinin; Stimulated; Morphogenesis

Understanding the control of cell division in plants by cytokinins (N6-substituted adenines) is becoming increasingly important as a model for cellular regulation in plants. Previous research on cytokinin-induced asymmetrical division in target caulonema cells of the moss Funaria has implicated a spatially controlled rise in intracellular calcium ion concentration as a second messenger that activates calmodulin. A model for cytokinin stimulation of cell division is proposed that suggests that the binding of cytokinin to asymmetrically localized plasma membrane receptors on target cells increases intracellular calcium from both intracellular and extracellular stores leading to calcium-dependent protein kinase activation and protein phosphorylation/dephosphorylation. Both the spatial and temporal changes in intracellular calcium and the protein phosphorylation appear to be involved in the profound cytoplasmic rearrangements seen after hormone treatment. It is becoming increasingly clear that covalent modification of preexisting proteins by phosphorylation is a major mechanism in the regulation of cell growth and differentiation. Calcium and protein phosphorylation may play a synergistic role in cytokinin control of cellular function. The goals of the current project are to: 1. characterize cytokinin binding sites by photoaffinity labeling using 8-azido benzyladenine, 2. analyze the localization of cytokinin binding using antibodies directed against cytokinins, 3. analyze calcium uptake using metallochromic indicators, and 4. monitor the cytoskeletal rearrangements, ion changes and phosphorylation patterns after hormone treatment. This research will increase our understanding of cytokinin signalling, the second messenger role of calcium, and the amplification of cellular response by protein phosphorylation leading to developmental changes in plants.

了解植物细胞分裂的控制， 细胞分裂素（N6-取代的腺嘌呤）正变得越来越多 作为植物细胞调节的重要模型。 细胞分裂素诱导细胞不对称分裂的前期研究 目标茎丝细胞的苔藓Funaria已经暗示了 细胞内钙离子空间控制性升高 浓度作为激活钙调素的第二信使。 提出了一个细胞分裂素刺激细胞分裂的模型 这表明细胞分裂素与不对称的 靶细胞上的局部质膜受体增加 来自细胞内和细胞外的细胞内钙 导致钙依赖性蛋白激酶激活的储存 和蛋白质磷酸化/去磷酸化。 无论是空间 以及细胞内钙和蛋白质的时间变化 磷酸化似乎参与了 激素处理后可见细胞质重排。 是 越来越清楚的是， 通过磷酸化的预先存在的蛋白质是一个主要机制， 细胞生长和分化的调节。 钙和 蛋白磷酸化可能在细胞分裂素中起协同作用 控制细胞功能。 当前项目的目标 1.表征细胞分裂素结合位点， 使用8-叠氮基苄基腺嘌呤的光亲和标记，2.分析 使用抗体定位细胞分裂素结合， 抗细胞分裂素，3.分析钙的摄取， 金属变色指示剂，和4.监测细胞骨架 重排，离子变化和磷酸化模式后， 激素治疗 这项研究将增加我们对细胞分裂素的了解 信号传导，钙的第二信使作用， 通过蛋白磷酸化放大细胞反应 导致植物的发育变化。