The role of protein tyrosine phosphatase δ in axon guidance

蛋白酪氨酸磷酸酶δ在轴突引导中的作用

• 批准号: 15590250
• 负责人: NAKAMURA Fumio
• 金额: $ 2.3万
• 依托单位: Yokohama City University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15590250/
• 关键词: Protein tyrosine phosphatase; Neuropilin-1; PTPδ; Semaphorin; Sema3A; axon guidance; ニューロピリン; プレキシン

The relation between Semaphorin-3A (Sema3A) signaling and LAR class protein tyrosine phosphatases, LAR, PTPδ and PTPσ, was investigated. I found that the ectodomains of PTPδ and PTPσ but not LAR bind to Neuropilin-1 (NRP1). Using alkaline phosphatase (AP) fusion proteins, I have determined the binding constant of the ectodomains PTPδ/σ. AP-PTPδ and AP-PTPσ bind NRP1 with Kd values of 1.1nM and 1.9nM, respectively. AP-Sema3A binds to NRP1 with a Kd of 0.19nM at the same condition. The first immunoglobulin domain of PTPδ/σ binds to the CUB domain of NRP1, which is the binding site for Sema3A. The ecdodomains of PIPδ/σ suppress Sema3A-induced growth cone collapse of dorsal root ganglion neurons. Ectopically expressed a cytoplasmic deletion mutant of PTPδ in the neurons suppresses the response. Surprisingly, overexpression of a phosphatase inactive mutant of PTPδ, but not of wild-type PIPδ, interferes Sema3A-response in the neurons. COS-7 cells co-expressing NRP1 and PIPδ reduce the adhered area upon Sema3A stimulation. This response is completely abolished with the phosphatase inactive mutant of PTPδ. Neither LAR nor PTPσ mediate. the response. Furthermore, NRP1 is co-immunoprecipitated with PTPδ from mouse embryonic brain. These results suggest that the extracellular domains of PTPδ/σ insulate NRP1 from Sema3A binding while full-length PTPδ mediates Sema3A signaling via its phosphatase domains.

研究了Semaphorin-3a（SEMA3A）信号传导与LAR类蛋白酪氨酸磷酸酶（LAR，PTPδ和PTPσ）之间的关系。我发现PTPδ和PTPσ的外生域不结合Neuropilin-1（NRP1）。使用酒精磷酸酶（AP）融合蛋白，我确定了胞外域PTPδ/σ的结合常数。 AP-PTPδ和AP-PTPσ分别以1.1nm和1.9nm的KD值结合NRP1。 AP-SEMA3A在相同条件下以KD为0.19nm与NRP1结合。 PTPδ/σ的第一个免疫球蛋白结构域与NRP1的CUB结构域结合，NRP1是SEMA3A的结合位点。 PIPδ/σ的co抑制了SEMA3A诱导的背根神经神经元的生长锥塌陷。异位表达神经元中PTPδ的细胞质缺失突变体抑制了反应。令人惊讶的是，PTPδ的磷酸酶无活性突变体的过表达，而不是野生型PIPδ的过表达会干扰神经元中的SEMA3A反应。共表达NRP1和PIPδ的COS-7细胞在SEMA3A刺激后降低了粘附区域。 PTPδ的磷酸酶无活性突变体完全消除了这种反应。 LAR和PTPσ都没有介导。反应。此外，NRP1与小鼠胚胎大脑的PTPδ共免疫沉淀。这些结果表明，PTPδ/σ的细胞外域与SEMA3A结合中的NRP1隔离，而全长PTPδ介质SEMA3A通过其磷酸酶域信号传导。