HUMAN BLOOD MONOCYTE RECEPTOR EXPRESSION AND MODULATION

描述：初步数据广泛。它证明了 信号转导模式和受体连接的后果 三种Fc受体(FcGammaRI、II和III以及受体A、B、C 异构体)在钙离子、酪氨酸的作用方面不同 受体的胞质尾部及其磷酸化 与伽马链和增量链相互作用。使用瞬时转基因 野生型和突变Fc受体的COS细胞构建 申请者展示了胞质尾部的酪氨酸磷酸化 完全连接需要FcGammaRII或Gamma或链的 以及通过Fc受体的吞噬作用。进一步的跨膜和 分子的胞外结构域，尽管它们调节 配体对受体的亲和力不会产生实质性影响 信令和功能后果。酪氨酸 磷酸化是通过激活和结合以下几种src- 相关蛋白酪氨酸激酶(PTK)和申请人展示 Syk的结合和激活，最一致的是在吞噬细胞中 PTK到伽马链(具有FcGammaRI和FcGammaRIII)和 FcgRII的胞质尾部。论证了SYK的重要性 通过SYK与FCRI共转染刺激FCRI吞噬功能 COS中的伽马链。此外，确切的数量和位置也很清楚 FcGammaII和ALL胞质尾部Y-Xn-L基序的研究 除了缺乏FcGammaRI的FcGammaRI以外，其他受体是至关重要的 以获得完整的吞噬信号。此外，很明显，在联合- 含FcGammaRI和Gamma链的COS的转染体 只有它有能力通过胞浆升高来结合免疫球蛋白和信号 Ca++，该信号不足以允许吞噬作用；然而， 与Gamma链共转染导致Gamma链磷酸化 和FcGammari的吞噬能力。具体而言， 申请人构造了函数替换的增益，通过添加 含有Y基序的适当数量和长度，吞噬作用 表达了有活性的FcGammaRII，它单独+/-伽马链 能传递完整的吞噬信号。额外的初步报告 研究表明这种Fc受体在健康和疾病中的重要性 细胞因子对受体的调节，一些证据表明PKC 而钙离子通过FcGammaRI介导的信号对细胞的分泌起重要作用。

DESCRIPTION: The preliminary data is extensive. It demonstrates that the mode of signalling and the consequences of receptor ligation via the three Fc receptors (FcgammaRI, II, and III and the receptors' A,B,C isoforms) differs with respect to the roles of Ca++, tyrosine phosphorylation, the cytoplasmic tail of the receptor and its interaction with gamma and delta chains. Using transient transfections of COS cells with wild type and mutagenized Fc receptor constructs the Applicant shows tyrosine phosphorylation of either the cytoplasmic tail of FcgammaRII or the gamma or chain are required for complete ligation and phagocytosis via the Fc receptors. Further the transmembrane and the extracellular domains of the molecule, although they regulate the affinity of ligand for receptor, do not materially affect signalling and the functional consequences. The tyrosine phosphorylation occurs via activation and binding of any of several src- related protein tyrosine kinases (PTK) and the Applicant demonstrated the binding and activation, most consistently in phagocytes, of the Syk PTK to the gamma chain (with the FcgammaRI and FcgammaRIII) and the cytoplasmic tail of the FcgRII. The importance of syk is demonstrated by ability of syk to stimulate FCRI phagocytosis via cotransfection with gamma chain in COS. Further, it is clear the exact number and placement of the motif Y-Xn-L in the cytoplasmic tail of the FcgammaRII and all other receptors, except the FcgammaRI where it is lacking, is critical for the complete phagocytic signal. Further it is clear in co- transfectants of COS with FcgammaRI and gamma chain that while the FcRI is alone competent to bind IgG and signal via elevation of cytosolic Ca++, this signal is insufficient to allow phagocytosis; however, cotransfection with gamma chain results in gamma chain phosphorylation and competence of the FcgammaRI for phagocytosis. In specific the Applicant constructed gain of function substitutions which by adding the appropriate number and length of the Y containing motif, a phagocytosis competent FcgammaRII was expressed, which alone +/- the gamma chain could transmit complete phagocytosis signal. Additional preliminary studies show the importance of this Fc receptors in health and disease the modulation of the receptor by cytokines, some evidence that the PKC and Ca++ mediated signal via the FcgammaRI is important for secretion.