Proteostasis, AMPylation and the Unfolded Protein repsonse (UPR)

蛋白质稳态、AMPylation 和未折叠蛋白反应 (UPR)

基本信息

批准号：
8914100
负责人：
Kim Orth
金额：
$ 31.09万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-03-01 至 2019-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8914100
关键词：
ATP phosphohydrolase ATPase Domain Active Sites Adenosine Monophosphate Aging Binding Sites Biochemical Bioinformatics Calcium Cell Death Cell Survival Cell physiology Cells Cellular Stress Chemicals Clustered Regularly Interspaced Short Palindromic Repeats Diabetes Mellitus Disease Drosophila melanogaster Endoplasmic Reticulum Enzymes Epitopes Eukaryota Eye GRP78 gene Glucose Goals Growth Homeostasis Human Infection Kinetics Knock-out Link Malignant Neoplasms Mediating Messenger RNA Modification Molecular Chaperones Molecular Conformation Neuroglia Normal Cell Outcome Oxidation-Reduction Pathway interactions Physiological Process Protein Overexpression Proteins Regulation SWI1 Signal Pathway Signal Transduction Site Stress System Testing Threonine Transcriptional Regulation Vibrio parahaemolyticus Virulence biological adaptation to stress blind cancer cell capitate bone endoplasmic reticulum stress fly insight pathogen prevent protein folding public health relevance response rho GTP-Binding Proteins stressor tool tumor

项目摘要

DESCRIPTION (provided by applicant): A variety of cellular processes are commonly subverted to encourage the proliferation of cancer cells, one of which is the unfolded protein response (UPR) that occurs in the endoplasmic reticulum (ER). In normal cells, improperly folded or glycosylated proteins will occasionally accumulate in the ER due to a variety of causes that are common in the tumor milieu (examples include altered glucose levels, redox state, calcium levels, and chemical stressors). The cell activates the UPR to prevent accumulation of unfolded proteins, which eventually leads to proteotoxicity and cell death. Importantly, heightened expression of BiP, an essential chaperone protein in the Endoplasmic Reticulum, is a critical factor for this survival mechanism in a variety of cancers. We have recently discovered a new form of BiP regulation, AMPylation by the protein FicD. We observe that FicD adds an adenosine monophosphate (AMP) molecule to a threonine near the ATP binding site of BiP during normal growth conditions. This modification rapidly disappears under multiple ER stress-inducing conditions. We hypothesize that this reversible modification inhibits the chaperone activity of a portion of cellular BiP, and this inhibition is relieved to increase the amount of acive chaperone during ER stress and promote cell survival. Our plan is to characterize the effect of FicD-mediated AMPylation on BiP and determine if the deAMPylating enzyme is a viable inhibition target. We want to understand the basic machinery and mechanisms involved in this signaling system. These studies will have great impact on the understanding of how this system is corrupted in cells with disrupted protein homeostasis (proteostasis), such as cancer, diabetes, prtein processing disorders and aging.

描述（由申请人提供）：多种细胞过程通常被破坏以促进癌细胞增殖，其中之一是正常细胞内质网（ER）中发生的未折叠蛋白反应（UPR）。由于肿瘤环境中常见的多种原因（例如，葡萄糖水平、氧化还原状态、钙水平和细胞化学应激源的改变），糖化蛋白或糖基化蛋白偶尔会在内质网中积聚。激活 UPR 以防止未折叠蛋白的积累，最终导致蛋白毒性和细胞死亡。重要的是，内质网中的重要伴侣蛋白 BiP 的丰富表达是多种癌症中这种生存机制的关键因素。最近发现了一种新形式的 BiP 调节，即蛋白质 FicD 的 AMP 化，我们观察到 FicD 在 ATP 附近的苏氨酸上添加了一个单磷酸腺苷 (AMP) 分子。我们发现，这种可逆修饰会抑制部分细胞 BiP 的伴侣活性，并且这种抑制会被缓解，从而增加活性伴侣的数量。我们的计划是表征 FicD 介导的 AMPylation 对 BiP 的影响，并确定去AMPylation酶是否是可行的抑制靶标。这些研究将对理解蛋白质稳态（蛋白质稳态）被破坏的细胞（例如癌症、糖尿病、蛋白质加工障碍和衰老）中该系统如何被破坏产生重大影响。