Characterization of the 72 kDa inositol polyphosphate 5-phosphatase

细胞对外界信号和环境做出反应，以进行细胞生长、分泌和/或其他特殊功能，包括控制细胞死亡和/或细胞大小。我们已经确定了一种新的酶(72 kDa 5-磷酸酶)，它存在于细胞内，我们有证据表明，它既调节细胞内小泡的运动，也调节胰岛素刺激的脂质信号。我们已经确定了这种酶分解的磷脂的特征，并展示了在细胞内膜上特定的亚细胞定位产生新的细胞信号。我们预测，这些特定脂质信号的产生可能在控制细胞内货物到细胞内特定位置的运输方面发挥重要作用。在这项拨款提案中，我们的目标是研究被称为葡萄糖转运体的特殊货物的调节，它存在于脂肪和肌肉细胞中，以及甘露糖6-磷酸受体，它调节调节蛋白质消化的特定酶的运输。这些研究包括澄清哪些磷脂发出酶终止的信号，以及这种信号在细胞中发生的位置。其次，我们将研究葡萄糖转运体GLUT-4在未受刺激的细胞中的运动以及对胰岛素的响应，以及这种新型酶的表达如何调节其运动。我们还将研究甘露糖6-磷酸受体的运动和特定的磷脂信号，这些信号控制着受体的运输路线，使用脂信号的抑制剂和脂磷酸酶和激酶的表达。我们还将研究我们的新型酶如何与细胞中的其他分子形成络合物，并使用酶活性和功能的基本生化评估来表征这些新型分子。最后，我们将研究我们的新型酶在胰岛素刺激后对细胞内信息的调节，它促进了葡萄糖进入细胞的吸收。

Cells respond to external signals and the enviroment to undergo cell growth, secretion and or other specialized functions including control of cell death and or cell size. We have identified a new enzyme (72 kDa 5-phosphatase) which resides inside the cell, which we have evidence plays a role in regulating both the movement of intracellular vesicles and also lipid signals stimulated by insulin. We have characterised the phospholipids that the enzyme cleaves and demonstrated the generation of new cell signals at specific subcellular localizations on intracellular membranes. We predict the generation of these specific lipid signals may play a significant role in controlling the transport of intracellular cargo to specific sites in the cell. In this grant proposal we aim to examine the regulation of specialised cargo called the glucose transporter, which is found in fat and muscle cells, and also the mannose 6-phosphate receptor, which regulates the trafficking of specific enzymes which mediate digestion of proteins. These studies include the clarification of which phospholipid signals the enzyme terminates and where in the cell this occurs. Secondly, we will examine the movement of the glucose transporter GLUT-4 in unstimulated cells and in response to insulin and furthermore how expression of the novel enzyme regulates its movement. We will also examine the movement of the mannose 6-phosphate receptor and the specific phospholipid signals which control the route the receptor traffics, using inhibitors of lipid signals and expression of lipid phosphatases and kinases. We will also examine how our novel enzyme forms complexes with other molecules in the cell and characterise these novel molecules using basic biochemical assessment of enzyme activity and function. Finally we will examine the regulation of intracellular messages by our novel enzyme following insulin stimulation, which facilitates glucose uptake into the cell.