Elucidating the molecular mechanisms of regulation of cellular stress sensors

对压力的反应是生物体生理和生物学中不可或缺的一部分。在为生存而进行的进化斗争中，适应压力条件是一个决定性的优势。内质网是位于细胞中央的细胞器，负责蛋白质和脂类的合成、折叠、细胞内钙的储存和释放等多种内务功能。许多内在或外在因素引起的内质网功能紊乱最终导致内质网应激，内质网启动一种应对反应[例如，未折叠蛋白反应(UPR)]来缓解或消除应激。UPR途径感知内质网干扰，涉及旨在重建蛋白质合成机制的不同成分，包括翻译衰减、编码伴侣和内质网相关降解成分的基因的转录激活，以及凋亡和自噬途径的激活。有三个内质网跨膜应激传感器组成了对内质网应激的UPR反应：PERK、ATF6和IRE1，它们是带有管腔应力敏感结构域的完整的内质网蛋白。我们的研究计划集中在识别参与调节细胞应力传感器的分子机制。 这项研究的长期目标是产生关于压力传感器分子机制的基础知识，并为参与该计划的HQP提供独特的培训机会。内质网管腔环境对UPR的管腔感受器结构域的调节仍然知之甚少。这项研究计划于2014年启动，旨在解决这一知识差距。我们发现内质网驻留蛋白(氧化还原酶、环氧合酶和钙调素)与IRE的内质网应激敏感结构域结合，从而影响其细胞信号转导。然而，控制这些相互作用的分子机制尚不清楚。此外，对其他内质网应激传感器的调节仍有待研究。为了解决这些问题，我们的研究计划有三个主题，重点是在相关ER驻留蛋白的存在下，使用重组的IRE1、PERK和ATF6管腔结构域在体外重建机制事件；以及评估内质网管腔环境是否参与这一过程。 主题1.确定ER管腔应力传感器的性质 主题2.研究PERK和ATF6 ER应激传感器的分子调控 主题3.确定内质网应激传感器调控的生物学重要性 这项研究计划将对内质网应激传感器生物学、分子相互作用在应激反应中的重要性以及促进我们对内质网应激应对反应的总体理解产生新的见解。我们还为HQP提供良好的环境，培训他们在行业和学术领域所需的技术和技能。衡量我们成功与否的较长期指标，将是学员担任学术研究人员、行业领袖或政府政策制定者等有影响力的高级职位的百分比。

Responses to stress are an integral part of organism's physiology and biology. Adaptation to stressful conditions is a decisive advantage in the evolutionary struggle for existence. The endoplasmic reticulum (ER) is a centrally located intracellular organelle responsible for many housekeeping functions including the synthesis, folding of proteins and lipids, the storage and release of intracellular calcium. Disruption of ER function caused by many intrinsic or extrinsic factors culminates in ER stress, and the ER mounts a coping response [e.g., unfolded protein response (UPR)] to mitigate or eliminate the stress. The UPR pathways sense ER disturbance and involves distinct components designed to re-establish the protein synthetic machinery, including translational attenuation, transcriptional activation of genes encoding chaperones and components of the ER-associated degradation, and activation of apoptotic and autophagy pathways. There are three ER transmembrane stress sensors that comprise the UPR reaction to ER stress: PERK, ATF6, and IRE1, integral ER proteins with luminal stress sensing domains. Our research program is focused on identifying the molecular mechanisms involved in the regulation of cellular stress sensors. Long-term objectives of this research are to generate fundamental knowledge regarding molecular mechanisms of stress sensors and to provide unique training opportunity for HQP engaged in the program. Regulation of the luminal sensor domain of UPR by the ER luminal environment remains poorly understood. This research program was initiated in 2014 to address this knowledge gap. We discovered that ER resident proteins (oxidoreductase, cyclooxygenase and calsequestrin) bind to ER luminal stress sensing domain of IRE to affect its cellular signaling. However, the molecular mechanisms governing these interactions are not known. Furthermore, regulation of other ER stress sensors remains to be examined. To address these our research program has three themes focused on reconstituting the mechanistic events in vitro, using recombinant IRE1, PERK and ATF6 luminal domain, in the presence of relevant ER resident proteins; and assessing whether ER luminal environment is involved in this process. Theme 1. Determine the nature of ER luminal stress sensors Theme 2. Examine molecular regulation of PERK and ATF6 ER stress sensors Theme 3. Determine biological importance of ER stress sensors regulation This research program will yield new insights on ER stress sensors biology, the importance of molecular interaction in stress sensing, as well as advance our general understanding of ER stress coping responses. We also provide outstanding environment for training of HQP in technologies and skills desired by industry and academic job sectors. Longer-term indicators of our success will be percentages of trainees reaching senior, influential positions as academic researchers, industry leaders or government policy makers.