Role of protein tyrosine phosphatases in organelle biogenesis

拟议的研究计划旨在了解蛋白酪氨酸磷酸酶在吞噬溶酶体（一种模式细胞器）生物发生中的作用。吞噬溶酶体的生物发生需要多种信号分子的协调作用，包括几种蛋白激酶，它们调节吞噬体和细胞骨架之间的相互作用，以及早期、晚期和再循环内吞区室。最近大规模的定量蛋白质组学和磷酸化蛋白质组学分析表明，酪氨酸磷酸化位点在吞噬体中的比例过高，相比于全球磷酸化蛋白质组。这一发现表明酪氨酸磷酸化在吞噬体信号传导中起重要作用。蛋白酪氨酸磷酸化的适当控制对于细胞内稳态是必不可少的，并且这是通过蛋白酪氨酸激酶和蛋白酪氨酸磷酸酶的平衡作用来实现的。蛋白酪氨酸磷酸酶在细胞器生物发生中的作用，特别是在控制吞噬溶酶体生物发生中，在很大程度上是未知的。我们的一般假设是蛋白酪氨酸磷酸酶参与吞噬溶酶体的生物合成。为了解决这一假设，我们提出了以下目标。 1.鉴定和表征与吞噬体相关的蛋白酪氨酸磷酸酶; 2.确定吞噬体相关蛋白酪氨酸磷酸酶在吞噬溶酶体生物发生中的作用; 3.利用蛋白质组学方法鉴定蛋白酪氨酸磷酸酶靶向的吞噬体蛋白。 拟议的研究计划将产生新的信息吞噬溶酶体生物合成的调节，以及在这一过程中的蛋白酪氨酸磷酸酶的作用。

The proposed research program is aimed at understanding the role(s) of protein tyrosine phosphatases in the biogenesis of phagolysosomes, a model organelle. Phagolysosome biogenesis requires the coordinated action of multiple signaling molecules, including several protein kinases, which regulate the interactions between the phagosome and the cytoskeleton, as well as the early, late and recycling endocytic compartments. A recent large scale quantitative proteomic and phosphoproteomic analyses revealed that tyrosine phosphorylation sites are overrepresented in phagosomes, as compared to global phosphoproteome. This finding suggests that tyrosine phosphorylation plays an important role in phagosome signaling. Appropriate control of protein tyrosine phosphorylation is essential for cellular homeostasis, and this is achieved by the balanced action of protein tyrosine kinases and protein tyrosine phosphatases. The role of protein tyrosine phosphatases in organelle biogenesis in general and in the control of phagolysosome biogenesis in particular, is largely unknown. Our general hypothesis is that protein tyrosine phosphatases participate in the biogenesis of phagolysosomes. To address this hypothesis, we propose the following Objectives. 1. To identify and characterize protein tyrosine phosphatases that associate with phagosomes; 2. To determine the role(s) of phagosome-associated protein tyrosine phosphatases in phagolysosome biogenesis; 3. To identify phagosome proteins targeted by protein tyrosine phosphatases using using a proteomic approach. The proposed research program will yield novel information on the regulation of phagolysosome biogenesis, as well as on the role of protein tyrosine phosphatases in this process.