Moleculap biological and Pustochemical study on phospholipid me tabolic enzymes inviolved in signal transduction

参与信号转导的磷脂代谢酶的分子生物学和化学研究

基本信息

批准号：
07457001
负责人：
KONDO Hisatake
金额：
$ 4.93万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Phosphoinositides (PI) turnover produces second messengers such as ciacylglycerol (DG) and inositol triphosphate in response to external stimuli. In addition, its intermediate products such as PI 4-monophosphate (PI4-P), PI4,5-bisphosphate (PI4,5-P) play roles in the membrane transport. It is thus important to clarify the molecular identity and characteristics of enzymes involved in the PI turnover for understanding the signal transduction and membrane transport. The present study addressed this point and revealed the molecular feature of DG kinase and PI 4-kinase, and localized them at mRNA levels in the brain of developing and adult rats by in situ hybridization histochemistry. DG kinase converts DG to phosphatidic acid (PA), and PI 4-kinase phosphorylates phosphatidyl-inositol to produce PI 4,5-P.Four subtypes of DG kinase (termed type I-IV) were identified by gene cloning from rat brain. The DG kinase type I is of soluble form and localized in the oligodendrocyte, but not neurons, … More and the absence of its expression is seen in the brain of myelin-deficient (shiverer) mice, suggesting the role in formation and maintenance of the myelin. The type II DG kinase is of membrane-associated form and localized in the medium-spiny neurons, neurons in the nucleus accumbens and olfactory tubercle, and in the endocrine cells of the pituitary inermediate lobe, suggesting the involvement in the dopaminergic transmission. The type III is localized dominantly in the Purkinije neurons and substantially in the granule cells of the cerebellum, suggesting its role in the cerebellar motor-control. The type IV is localized in the cerebral and cerebellar cortical neurons, but peculiar in the molecular structure : while the former three contain two EF-hand and zinc-finger motifs in addition to the ATP-binding domain, the type IV contains no EF-hand motifs, but possesses ankyrin-like repeats. This structure has a high homology to rdgA (a gene of Drosophila inducing the retinal degeneration), but this rat molecule is localized in the bipolar cell, but not the photoreceptor cell of the retina, suggesting some different roles for this homologous molecule between different animal species.Two subtypes of PI 4-kinase were idenfified with the molecular weight of 230kDa and 92kDa. The former has a high homology to Pikl and the latter to Stt4, both of which are yeast PI 4-kinases and has previously been cloned by other authors. Both PI 4-kinases are localized at mRNA levels widely in almost all neurons with much higher expression in immature cells. When overexpressed in COS-cells, these molecules are localized in the Golgi apparatus. It is thus suggested that these PI 4 kinases are involved in the vesicle-transport within cells. Less

磷酸肌醇（PI）营业额产生了第二个使者，例如ciacylglycer（DG）和三磷酸肌醇，响应外部刺激，其中间产品，例如PI 4-磷酸盐（PI4-P），PI4，PI4，5-磷酸盐（PI4,5）（PI4,5,5） -p）在膜中发挥作用。并通过原位杂交组织化学将它们定位在发育和成年大鼠的大脑中。 DG激酶（称为I型IV）是通过大鼠脑的基因clong鉴定的。在形成和髓磷脂中的作用。在小脑中，在小脑运动型中，在小脑中的颗粒细胞中基本上结合结构域，IV型不包含EF手基序，但具有脚踝蛋白样的重复。不同的 - 激酶之间的分子与230kDa和Da的分子量相同，前者对Pikl具有很高的同源性，而后者则具有其他作者。在高尔基体中，未成熟的细胞