Genetic Dissection of Yeast Bax Inhibitor Function in UPR and Calcium Signaling

描述(申请人提供)：Bax抑制因子-1(BI-1)是一种含有内质网(ER)的六跨膜驻留蛋白，在动物和植物中都具有细胞保护功能。它在各种不同的人类肿瘤中表达上调，如间变性大细胞淋巴瘤、前列腺癌和乳腺癌以及急性髓系白血病。Bax抑制剂的确切生物学功能尚不清楚。在哺乳动物细胞中，一些研究得出结论，BI-1可能通过抑制未折叠蛋白反应(UPR)的信号来保护细胞免受内质网应激诱导的细胞程序性死亡(PCD)。它似乎还调节内质网和胞浆中的钙离子浓度。然而，尽管有这些已发表的研究，仍然不清楚Bax抑制剂在调节UPR中的作用是否(如果是，如何)与其在细胞钙水平调节中的作用有关。因此，有必要解决该领域的一个紧迫问题：Bax抑制剂是否通过调节细胞内钙水平来调节细胞钙水平 普遍定期审议(或反之亦然)，还是独立完成这些职能？为了填补这一知识空白，我在普罗维登斯学院的实验室启动了现已发表的研究，以调查酿酒酵母Bax抑制剂同系物的功能，我们称之为BXI1。在这个R15区域的提案中，我们描述了以我们已发表的数据为基础的遗传学-主要是上位性-实验，以继续使用酵母遗传学的力量来表征Bax抑制剂的两个功能之间的联系，即UPR的调节和钙信号的调节。我们预计我们的研究计划将产生积极的影响，因为这些遗传学研究不仅应该帮助我们更好地了解Bax抑制物在细胞程序性死亡和癌症中的功能，而且还可以揭示UPR和钙信号之间的功能联系。由于内质网应激和UPR与多种人类疾病有关，我们预计我们的研究计划将对探索这些和其他涉及内质网应激和UPR的疾病的生物学基础的领域产生积极影响。最后，除了更全面地扩展我们在内质网应激和癌症方面的知识库，更具体地说，资助这一领域R15拨款提案中描述的研究，还将使我的实验室和我们普罗维登斯学院的系改善我们的研究基础设施，以便我们能够继续培训有才华的本科生，并为他们在生物医学科学领域的成功职业生涯做好准备。

DESCRIPTION (provided by applicant): Bax inhibitor-1 (BI-1) is a six-transmembrane containing endoplasmic reticulum (ER) resident protein that provides cytoprotective functions in both animals and plants. It is up regulated in a variety of different human tumors like anaplastic large cell lymphoma, prostate and breast carcinoma, and acute myeloid leukemia. The precise biological function of Bax inhibitor remains unclear. In mammalian cells, several studies conclude that BI-1 may protect cells from ER-stress induced programmed cell death (PCD) by suppressing the signaling of the unfolded protein response (UPR). It also appears to regulate the concentration of Ca2+ in the ER and the cytosol. Despite these published studies, however, it is still not clear whether (and if it is, how) Bax inhibitor's role in the regulation of the UPRis linked to its role in the regulation of cellular calcium levels. Therefore there is a need to answe a pressing question in the field: Does Bax inhibitor regulate cellular calcium levels by regulating the UPR (or vice versa) or does it accomplish these functions independently? To fill this knowledge gap, my laboratory at Providence College initiated now-published studies to investigate the function of the Saccharomyces cerevisiae Bax inhibitor homolog, which we have called BXI1. In this R15 AREA proposal, we describe genetic - primarily epistatic - experiments that build upon our published data to continue to use the power of yeast genetics to characterize the link between the two functions of Bax inhibitor, the regulation of the UPR and the regulation of calcium signaling. We expect our research program to have a positive impact because these genetic studies should help us not only to better understand Bax inhibitor function in programmed cell death and cancer but also to uncover functional links between the UPR and calcium signaling. Since ER stress and the UPR have been implicated in a variety of human diseases we anticipate that our research program should have a positive impact on fields exploring the biological basis for these and other diseases that involve ER stress and the UPR. Finally, in addition to expanding our knowledge base in ER-stress and cancer more generally and in Bax inhibitor's mechanism of action more specifically, funding the research described in this AREA R15 grant proposal will also allow my laboratory and our department here at Providence College to improve our research infrastructure so that we can continue to train and to prepare talented undergraduate students for successful careers in the biomedical sciences.