DUAL AND OPPOSING ROLES OF SHP 2 IN CNTF SIGNALING

含Src同源2(SH2)结构域的酪氨酸蛋白的描述 磷酸酶SHP-2被认为是一种重要的正调控因子 几条促有丝分裂信号通路。SHP-2最近被证明是 酪氨酸被磷酸化，并被招募到Gp130/LIFR亚基上 睫状神经营养因子刺激的CNTF受体复合体 (CNTF)。然而，CNTF对反应性不具有增殖作用。 而是增强交感神经的存活和分化， 运动神经元和感觉神经元。在初步研究部分， 申请人证明了干扰SH2结构域突变体的表达 SHP-2在神经母细胞瘤细胞系中的表达增加CNTF诱导的 血管活性肠肽(VIP)报告基因及其培养 交感神经元导致内源性VIP物质上调 P(SP)和胆碱乙酰转移酶(ChAT)基因表达。他们也 平行研究发现，SHP-2干扰突变体的表达 取消CNTF诱导的c-Fos蛋白水平。国家交流会成员 细胞因子家族通过激活信号通路传递信号 同时涉及STAT和Fos-Jun(AP-1)转录因子并被激活 STAT是诱导VIP基因所必需的。综合来看，这些数据 表明SHP-2在信令级联中具有双重和相反的角色 由相同的配体触发，如其负功能在 血管活性肠肽、SP和ChAT水平的诱导及其在脑出血中的积极作用 C-Fos水平。在这项提案中，他们将详细研究 它们被CNTF等神经细胞因子激活，并定义了 SHP-2如何调节这些平行信号通路的机制。

DESCRIPTION The src homology 2 (SH2) domain-containing protein tyrosine phosphatase SHP-2 has been implicated as an important positive regulator of several mitogenic signaling pathways. SHP-2 has more recently been shown to be tyrosine phosphorylated and recruited to the gp130/LIFR subunits of the CNTF receptor complex upon stimulation with ciliary neurotrophic factor (CNTF). CNTF does not, however, have a proliferative effect on responsive cells, but rather enhances the survival and differentiation of sympathetic, motor, and sensory neurons. In the Preliminary Studies section the applicants demonstrate that expression of an interfering SH2 domain mutant of SHP-2 in a neuroblastoma cell line increases CNTF induction of a vasoactive intestinal peptide (VIP) reporter gene and in cultures of sympathetic neurons results in an upregulation of endogenous VIP, substance P (SP) and choline acetyltransferase (ChAT) gene expression. They also found in parallel studies that expression of the SHP-2 interfering mutant abolishes CNTF induction of c-Fos protein levels. Members of the CNTF family of cytokines transmit their signal by activating signaling pathways involving both STAT and Fos-Jun (AP-1) transcription factors and activated STAT is necessary for induction of the VIP gene. Taken together, these data indicate that SHP-2 has dual and opposing roles in a signaling cascade triggered by the same ligand, as illustrated by its negative function in induction of VIP, SP and ChAT levels and positive function in induction of c-Fos levels. In this proposal they will examine in detail the pathways that are activated by neurocytokines such as CNTF and define the molecular mechanisms of how SHP-2 regulates these parallel signaling pathways.