权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Demonstration of multiforms of insect cytokine receptors

多种形式的昆虫细胞因子受体的演示

基本信息

批准号：
14340261
负责人：
HAYAKAWA Yoichi
金额：
$ 10.62万
依托单位：
Saga University (2004-2005)Hokkaido University (2002-2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

项目摘要

Growth-blocking peptide (GBP) is a member of an insect cytokine family. GBP is a small peptide consists of 25 amino acid residues, but it exerts diverse functions including larval growth retardation, cell proliferation, paralysis induction, cardioacceleration, immune cell stimulation, and morphogenesis. In this study, deletion analogs of GBP were synthesized to investigate the relationship between the structure of GBP and the biological activities such as mitogenic and plasmatocyte (a type of hemocytes) spreading activities. The results indicated that the minimal structure of GBP containing mitogenic activity is 2-23 GBP, whereas that with plasmatocyte spreading activity is 1-22 GBP, indicating the possibility that multifunctional properties of this peptide may be mediated by different forms of GBP receptors. In order to demonstrate this speculation, we analyzed GBP receptors in different types of cells by a competitive receptor binding assay with ^<125>I-GBP. The results showed that High Five cells contain two types of GBP receptors : high affinity (K_d=0.26) and low affinity (K_d=13.7), while hemocytes contain a single class of GBP receptor with a medium affinity (K_d=1.26). These results demonstrated a heterogeneity of GBP receptors at least in insect culture cells and hemocyte cells. Further, we identified two different types of GBP receptor candidates in hemocytes, approximately 60 kDa and 77 kDa proteins. The former protein does not contain any distinct domain structures other than one transmembrane domain. However, the latter protein contains one transmembrane domain, and ITAM (immunoreceptor tyrosine-based activation motif) and IgG like domains in the outer cell region and inner cell region, respectively. We further found that tyrosine residues in the cytoplasmic region of this molecule are phosphorylated by GBP. We are now trying to demonstrate whether GBP specifically binds to these cell membrane proteins.

生长阻断肽（Growth-blocking peptide，GBP）是昆虫细胞因子家族的一员。GBP是由25个氨基酸残基组成的小肽，但它发挥多种功能，包括幼虫生长迟缓、细胞增殖、麻痹诱导、心脏加速、免疫细胞刺激和形态发生。本研究合成了GBP的缺失类似物，以研究GBP的结构与其生物活性如促有丝分裂活性和浆细胞（一种血细胞）铺展活性之间的关系。结果表明，具有促有丝分裂活性的GBP的最小结构为2-23 GBP，而具有浆细胞铺展活性的GBP的最小结构为1-22 GBP，表明该肽的多功能特性可能由不同形式的GBP受体介导。为了证明这一推测，我们通过与β I-GBP的竞争性受体结合试验分析了不同类型细胞中的GBP受体<125>。结果表明，High Five细胞含有高亲和力（Kd =0.26）和低亲和力（Kd =13.7）两种GBP受体，而血细胞只含有一种中等亲和力（Kd =1.26）的GBP受体。这些结果表明至少在昆虫培养细胞和血细胞中GBP受体的异质性。此外，我们在血细胞中鉴定了两种不同类型的GBP受体候选物，约为60 kDa和77 kDa蛋白质。前一种蛋白除了一个跨膜结构域外不含任何不同的结构域结构。然而，后一种蛋白质含有一个跨膜结构域，以及分别位于外细胞区和内细胞区的ITAM（基于免疫受体酪氨酸的激活基序）和IgG样结构域。我们进一步发现，酪氨酸残基在该分子的胞质区域被磷酸化的GBP。我们现在正试图证明GBP是否特异性结合这些细胞膜蛋白。