REGULATION OF BETA CELL GENES BY GLUCOSE AND INCRETINS

葡萄糖和肠促胰素对 β 细胞基因的调节

• 批准号: 8171328
• 负责人: MARC R MONTMINY
• 金额: $ 0.24万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8171328
• 关键词: 14-3-3 Proteins; Address; Beta Cell; CREB1 gene; Calcineurin inhibitor; Calcium; Calcium Signaling; Cell Death; Cell Nucleus; Cell Survival; Complex; Complication; Computer Retrieval of Information on Scientific Projects Database; Cues; Cyclic AMP; Cytoplasm; Diabetes Mellitus; EP300 gene; FK506; Family; Funding; Gene Expression; Genes; Genetic Programming; Genetic Transcription; Glucose; Grant; Immunosuppression; Institution; Insulin; Islet Cell; Islets of Langerhans; Knock-out; Mediating; Modification; Mus; Mutation; Nuclear; Pathway interactions; Patients; Phosphorylation; Process; Protein Kinase; Proteins; RNA Interference; Regulation; Relative (related person); Research; Research Personnel; Resources; Role; Source; Transducers; Transplantation; United States National Institutes of Health; calcineurin phosphatase; feeding; incretin hormone; inhibitor/antagonist; islet; mutant; novel; pancreatic islet function; paralogous gene; polypeptide; promoter; response

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Glucose and incretin hormones trigger the expression of genetic programs that enhance islet cell survival and promote insulin release during feeding. The activation of cAMP and calcium pathways in response to these cues promotes islet gene expression and beta cell survival in part by stimulating the phosphorylation of CREB at Ser133, a modification that stimulates recruitment of the coactivator paralogs CBP and P300 to the promoter. Mice with knockin mutations in CBP and P300 that disrupt their association with CREB show only modest changes in cAMP dependent transcription, however, suggesting the potential involvement of additional CREB coactivators in this process. The current proposal focuses on the role of a novel family of CREB coactivators, designated TORCs for Transducers of Regulated CREB activity, in promoting islet gene expression. Preliminary studies reveal that islet TORC proteins are retained in the cytoplasm under basal conditions, migrating to the nucleus in response to cAMP and calcium signals where they potentiate CREB target gene expression. Specific Aim I addresses the mechanism by which TORC activity is suppressed under basal conditions, focusing on the role of a TORC associated protein kinase in promoting TORC phosphorylation and cytoplasmic retention via an interaction with 14-3-3 proteins. Aim II addresses the mechanism of TORC activation in response to cAMP and calcium, with particular emphasis on the role of the ser/thr phosphatase calcineurin in dephosphorylating and promoting nuclear entry of TORC. Aim III examines the relative importance of CREB:TORC and CREB:CBP complexes for pancreatic islet gene expression by using mutant CREB polypeptides that are defective in either CBP or TORC interaction. Regulatory contributions of TORC and CBP/P300 towards CREB target gene expression islet cells will also be explored by disrupting the expression of each coactivator through RNAi mediated knockdown. Finally, the role of TORCs in pancreatic islet function will be determined by generating mice with a conditional knockout of the TORC genes. Post-transplant diabetes is a frequent complication in patients receiving calcineurin inhibitors such as FK506 for immunosuppression. The proposed studies will reveal whether these inhibitors promote islet cell death, in part by interfering with expression of islet survival genes through the CREB:TORC pathway.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目及 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 葡萄糖和肠促胰岛素激素触发遗传程序的表达，增强胰岛细胞的存活并促进进食期间胰岛素的释放。 cAMP 和钙途径响应这些信号而被激活，部分是通过刺激 CREB ​​Ser133 的磷酸化来促进胰岛基因表达和 β 细胞存活，这种修饰刺激了共激活子旁系同源物 CBP 和 P300 向启动子的募集。然而，CBP 和 P300 敲入突变破坏了它们与 CREB ​​的关联的小鼠仅表现出 cAMP 依赖性转录的适度变化，这表明额外的 CREB ​​共激活剂可能参与这一过程。目前的提案重点关注新型 CREB ​​共激活剂家族（指定为受调节 CREB ​​活性转导器的 TORC）在促进胰岛基因表达中的作用。初步研究表明，胰岛 TORC 蛋白在基础条件下保留在细胞质中，响应 cAMP 和钙信号迁移到细胞核，从而增强 CREB ​​靶基因的表达。具体目标 I 阐述了在基础条件下 TORC 活性被抑制的机制，重点关注 TORC 相关蛋白激酶通过与 14-3-3 蛋白相互作用促进 TORC 磷酸化和细胞质保留的作用。目标 II 探讨了 TORC 响应 cAMP 和钙而激活的机制，特别强调丝氨酸/苏氨酸磷酸酶钙调磷酸酶在 TORC 去磷酸化和促进 TORC 进入核中的作用。目标 III 通过使用 CBP 或 TORC 相互作用有缺陷的突变 CREB ​​多肽来检查 CREB:TORC 和 CREB:CBP 复合物对于胰岛基因表达的相对重要性。还将通过 RNAi 介导的敲低破坏每个共激活因子的表达来探索 TORC 和 CBP/P300 对 CREB ​​靶基因表达胰岛细胞的调节作用。最后，TORC 在胰岛功能中的作用将通过产生条件性敲除 TORC 基因的小鼠来确定。移植后糖尿病是接受钙调神经磷酸酶抑制剂（例如 FK506）进行免疫抑制的患者的常见并发症。拟议的研究将揭示这些抑制剂是否部分通过 CREB:TORC 途径干扰胰岛存活基因的表达来促进胰岛细胞死亡。