Bcl-2 function on the endoplasmic reticulum

描述(由申请人提供)：通过抑制细胞凋亡，Bcl2蛋白对肿瘤的发生和固有的癌症治疗耐药都有贡献。这项拨款支持的研究正在研究Bcl2的S作用机制的一个特殊方面，即抑制促进细胞凋亡的钙信号。我们发现，Bcl2与内质网(ER)上的三磷酸肌醇受体(IP3R)相互作用，从而抑制IP3诱导的钙升高。在当前的资助期间，我们使用FRET演示了这种相互作用在细胞中的作用，并绘制了Bcl-2和IP3R上的相互作用位点。基于这一信息，我们开发了一种抑制Bcl-2-IP3R相互作用的多肽，多肽2。当这种多肽被输送到细胞内时，可以逆转Bcl2对促凋亡钙信号的抑制，并触发长时间的钙振荡，从而提高促凋亡蛋白Bim。本研究通过研究Bcl2-IP3R相互作用调节IP3R通道活性从而抑制依赖于IP3的钙升高的基本机制来继续这项工作。此外，本研究还探讨了多肽2抑制Bc l-2-IP3R相互作用触发钙振荡和增加Bim水平的机制。最后，这项建议探索了靶向Bcl2-IP3R相互作用的概念，以与其他治疗药物协同治疗Bcl2过表达的癌症，包括慢性淋巴细胞性白血病。 与公共健康相关：bcl-2是一种非常重要的蛋白质，与癌症有关。它的功能是抑制细胞死亡。因此，当癌细胞含有过多的这种蛋白质时，它们就不会死亡。因此，癌细胞会积累，并对旨在诱导细胞死亡的治疗产生抵抗力。这项建议是为了研究更好地了解Bcl-2如何抑制细胞死亡。其目的是了解Bcl-2如何与癌细胞内传导钙离子的通道相互作用并进行调节。这些离子在调节细胞死亡方面很重要。我们的研究正在研究一种假说，即Bcl-2关闭这些通道，从而阻止钙离子诱导细胞死亡。通过了解这一过程，我们可能能够开发新的治疗癌症的方法，以克服Bcl-2的细胞死亡抑制功能。

DESCRIPTION (provided by applicant): The Bcl-2 protein contributes to both oncogenesis and intrinsic cancer treatment resistance by inhibiting apoptosis. Research supported by this grant is investigating one particular aspect of Bcl-2's mechanism of action, the inhibition of calcium signals that promote apoptosis. We discovered that Bcl-2 interacts with the inositol 1,4,5-trisphosphate receptor (IP3R), an IP3-gated calcium channel on the endoplasmic reticulum (ER), thus inhibiting IP3-induced calcium elevation. In the current funding period we used FRET to demonstrate this interaction in cells and mapped the interaction sites on both Bcl-2 and the IP3R. Based on this information we developed a peptide inhibitor of Bcl-2-IP3R interaction, Peptide 2. This peptide, when delivered into cells, reverses the inhibition of pro-apoptotic calcium signals by Bcl-2 and triggers prolonged calcium oscillations that elevate the pro-apoptotic protein Bim. The present proposal continues this work by investigating the fundamental mechanism by which Bcl-2-IP3R interaction regulates IP3R channel activity and thus inhibits IP3- dependent calcium elevation. Also, this proposal investigates the mechanism by which Peptide 2-mediated inhibition of Bcl-2-IP3R interaction triggers calcium oscillations and increases Bim levels. Finally, this proposal explores the concept of targeting Bcl-2-IP3R interaction for treatment of Bcl-2 over-expressing cancers, including chronic lymphocytic leukemia, in synergy with other therapeutic agents. PUBLIC HEALTH RELEVANCE: Bcl-2 is a very important protein that contributes to cancer. It functions to inhibit the death of cells. Therefore, when cancer cells have too much of this protein they fail to die. Thus, the cancer cells accumulate and are resistant to treatments designed to induce cell death. This proposal is for research to better understand how Bcl-2 inhibits cell death. The goal is to understand how Bcl-2 interacts with and regulates channels that conduct calcium ions within cancer cells. These ions are important in mediating cell death. Our research is investigating the hypothesis that Bcl-2 closes these channels and thus prevents the calcium ion from inducing cell death. By understanding this process we may be able to develop new treatments for cancer that overcome the cell death inhibiting function of Bcl-2.