Control of efflux transporter activity by cell surface reorganization in embryos.

描述（由申请人提供）：本研究的总体目标是了解早期胚胎发育过程中多药物外流转运活性的细胞生物学调节。 该应用程序将两个知识体系联系起来，即多药物外排运输的功能生理学，主要在癌症和上皮运输的背景下研究，以及细胞表面和膜组织的结构变化，主要在细胞和发育生物学的背景下研究。 在此应用中，候选人将描述海胆和小鼠这两种模型生物中早期胚胎发育中发生的细胞表面变化与外排转运蛋白活性的伴随变化之间的关系。 细胞生物学方面是了解细胞刺激如何快速改变运输活动，特别是结构（微绒毛运动）和功能（防止有毒物质进入细胞）之间的关系。 发育生物学方面是了解未受精卵的膜如何从专门与精子融合的膜转变为现在保护和调节后续发育的膜。 该候选人的博士后研究揭示了海胆卵受精后 ABCB (pgp) 和 ABCC (mrp) 外排转运蛋白活性的大规模和快速上调。 在大多数细胞中，多药物转运蛋白持续插入细胞膜，而在海胆中，这种情况在受精后迅速发生。 因此，海胆为研究这种现象提供了一个强有力的模型。 在前两个目标中，候选人将通过转运蛋白移动到微绒毛尖端来表征 Sp-ABCB1a（哺乳动物 pgp 的直系同源物）活性的受精后重新分布（目标 1）以及 Sp-ABCB1a 在活胚胎中定位的动态（目标 2）。 此后，他将把这些发现扩展到小鼠模型，特别是对小鼠卵母细胞受精后 pgp 转运蛋白活性丧失的初步发现进行跟踪（目标 3）。

DESCRIPTION (provided by applicant): The overall goal of this research is to understand the cell biological regulation of multidrug efflux transport activity during early embryo development. This application links two bodies of knowledge, the functional physiology of multidrug efflux transport, primarily studied in the context of cancer and epithelial transport, and the structural changes in cell surface and membrane organization, primarily studied in the context of cell and developmental biology. In this application, the candidate will characterize the relationship between cell surface changes that occur in early embryo development and the concomitant changes in the efflux transporter activity in two model organisms, the sea urchin and the mouse. The cell biology side is to understand how transport activity can be rapidly changed by cell stimuli and especially the relationship between structure (movement to microvilli) and function (prevention of entry of toxicants into the cell). The developmental biology side is to understand how the membrane of the unfertilized egg is altered from one specialized to fuse with the sperm to one that now protects and regulates subsequent development. The candidate's postdoctoral research has revealed massive and rapid up-regulation of ABCB (pgp) and ABCC (mrp) efflux transporter activity following fertilization of sea urchin eggs. In most cells insertion of multidrug transporters into the membrane is continuous, whereas in the sea urchin this occurs rapidly after fertilization. Thus, the sea urchin provides a powerful model for studying this phenomenon. In the first two aims, the candidate will characterize the post-fertilization redistribution of Sp-ABCB1a (an ortholog of mammalian pgp) activity by movement of the transporter to the tips of microvilli (Aim 1) and the dynamics of Sp-ABCB1a localization in living embryos (Aim 2). Thereafter, he will extend these findings to the mouse model, specifically following up on the preliminary finding of loss of pgp transporter activity after fertilization of mouse oocytes (Aim 3).