CONTROL OF CALCIUM AND PHOSPHORYLATION-REGULATED SIGNALLING PATHWAYS

钙的生理和分子生物学研究进展 而磷蛋白调节的信号通路已经被 启动，重点是钙调素(CaM)依赖 磷酸酶、钙调神经磷酸酶(CN)和环核苷酸 磷酸二酯酶(PDE)。免疫细胞化学研究表明 大脑PDE的钙调蛋白依赖的亚型被表达 主要在区域输出神经元中，与一个角色一致 在整合突触输入方面。此外，化学破坏 小脑浦肯野细胞的攀升纤维传入引起 PDE免疫反应性丧失提示存在跨突触模型 基因表达的调控。关于克隆的研究现状 这种酶的设计是为了确定控制机制(S) 表情。最近的研究表明，CN是主要的 胞浆CaM结合蛋白(BP)在淋巴细胞中的表达 在淋巴样细胞亚群中差异表达。至 检查它在免疫系统(和大脑)中的调节，cDNA 该磷酸酶的催化亚基已被克隆 表达载体的免疫筛选及新型斑块杂交法 方法使用生物素化的限制性片段。组织- 目前正在对特定的信使核糖核酸进行鉴定和体外实验。 将进行突变以检测重要的变构和 酶上的催化域，其中一些是由 与最近克隆的其他磷酸酶有明显的相似性。正在进行中 使用模型磷酸肽的研究将被用于研究 免疫学上受体和蛋白质的磷酸化 参与中间代谢和细胞骨架的控制 组织。

Investigations on the physiology and molecular biology of calcium and phosphoprotein-regulated signalling pathways have been initiated, with emphasis on the calmodulin (CaM)-dependent phosphatase, calcineurin (CN), and cyclic nucleotide phosphodiesterase (PDE). Immunocytochemical studies indicate that the calmodulin-dependent isoform of brain PDE is expressed predominantly in regional output neurons, consistent with a role in integration of synaptic input. Further, chemical destruction of climbing fiber afferents to cerebellar Purkinje cells causes loss of PDE immunoreactivity suggesting a "transsynaptic" model for regulation of gene expression. Current studies on the cloning of this enzyme are designed to determine the control mechanism(s) for expression. Recent studies have shown that CN is the major cytosolic CaM-binding protein (BP) in lymphocytes and that it is differentially expressed in subpopulations of lymphoid cells. To examine its regulation in the immune system (and brain), cDNAs for the catalytic subunit of this phosphatase have been cloned using expression vector immunoscreening and a novel plaque hybridization method employing biotinylated restriction fragments. Tissue- specific mRNA species are now being characterized and in vitro mutagenesis will be carried out to examine important allosteric and catalytic domains on the enzyme, some of which are suggested by clear similarities to other recently cloned phosphatases. Ongoing studies with model phosphopeptides will be used to investigate immunologically the phosphorylation of receptors and proteins involved in control of intermediary metabolism and cytoskeletal organization.