Functional analysis of the CAMTA Transcription Factors

CAMTA转录因子的功能分析

• 批准号: 8318632
• 负责人: HONG-SHENG LI
• 金额: $ 32.09万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8318632
• 关键词: Aging; Alzheimer' s Disease; Apoptosis; Binding; Brain; Calcium; Calmodulin; Cations; Cells; Defect; Disease; Drosophila eye; Family; Feedback; G-Protein-Coupled Receptors; Gene Expression; Gene Targeting; Goals; Homeostasis; Human; Immunologic Deficiency Syndromes; Knowledge; Light; Mediating; Modeling; Myosin III; Names; Nerve Degeneration; Neurons; Nuclear; Pathway interactions; Phospholipase C; Phototransduction; Physiological; Prevention; Proteins; Research; Rhodopsin; Signaling Molecule; Spinocerebellar Ataxia Type 4; Spinocerebellar Ataxias; TRP channel; Testing; Transcription Coactivator; cell type; fly; human disease; photoreceptor degeneration; public health relevance; receptor; sensor; transcription factor

DESCRIPTION (provided by applicant): The long-term goal of our research is to understand how cells maintain intracellular Ca2+ homeostasis in diverse physiological conditions. As a versatile signaling molecule, Ca2+ regulates the proliferation, differentiation, function, aging, and apoptosis of virtually all types of cells. Abnormal calcium homeostasis may cause damage to the cell, and has been implicated in aging and in numerous human diseases, such as Alzheimer's disease and spinocerebellar ataxia. To avoid undesirable effects of Ca2+, all pathways of Ca2+ entry are tightly controlled in the cell. A group of ubiquitously expressed Ca2+ influx channels, termed receptor-operated Ca2+/cation channels (ROCs), are stimulated by G protein-coupled receptors (GPCRs) through Gq/11 proteins and phospholipase C (PLC). Since most GPCRs and ROCs have much higher protein levels in excitable cells including neurons, to maintain the intracellular Ca2+ homeostasis, these cells need to fortify the regulatory machinery of GPCR/ROC by expressing more regulatory molecules. We have previously demonstrated that dCAMTA, a transcription factor responding to the Ca2+ sensor calmodulin, is indispensable for rapid deactivation of the light-stimulated GPCR rhodopsin in the Drosophila eye. dCAMTA belongs to a new family of transcription factors named calmodulin-binding transcription activators (CAMTAs). Interestingly, both human CAMTAs, CAMTA1 and CAMTA2, are highly expressed in the brain. We predict that the calmodulin/CAMTA-stimulated gene expression may fortify the control machinery of GPCR/ROC-mediated Ca2+ entry in neurons, in a long-term feedback manner. To test this hypothesis, we propose to use dCAMTA as model and to take advantage of the fly phototransduction cascade, a typical GPCR/PLC cascade that has been successfully used for the identification of the first ROC channel TRP. In this proposal, we will 1. Test the hypothesis that the dCAMTA target gene dFbxl4 is indispensable for rapid deactivation of rhodopsin; 2. Test the hypothesis that dFbxl4 interacts with the myosin III NINAC for rhodopsin deactivation; 3. Test the hypothesis that dCAMTA promotes expression of calmodulin to facilitate the deactivation of rhodopsin; 4. Test the hypothesis that loss of dCAMTA leads to Ca2+-dependent, vacuolar photoreceptor degeneration in older flies; 5. identify the nuclear localization sequences of dCAMTA and human CAMTA1; 6. Test the hypothesis that Fbxl4 and/or cam1 are target genes of human CAMTA1. PUBLIC HEALTH RELEVANCE: Defects in calcium homeostasis have been implicated in a variety of human disorders including several neurodegeneration diseases (Alzheimer's disease and spinocerebellar ataxia) and several forms of immunodeficiency The long- term goal of this research is to fully understand how the intracellular Ca2+ homeostasis is maintained in both physiological and pathological conditions and to use this knowledge to facilitate treatment and perhaps prevention of these human diseases. This proposal will study how a new group of transcription factors regulate the Ca2+ homeostasis in a feedback manner.

描述（由申请人提供）：我们研究的长期目标是了解细胞如何在不同的生理条件下维持细胞内Ca 2+稳态。作为一种多功能的信号分子，Ca 2+调节几乎所有类型细胞的增殖、分化、功能、衰老和凋亡。异常的钙稳态可能会导致细胞损伤，并与衰老和许多人类疾病有关，如阿尔茨海默病和脊髓小脑共济失调。为了避免Ca 2+的不良影响，细胞中Ca 2+进入的所有途径都受到严格控制。一类广泛表达的Ca 2+内流通道，称为受体操纵的Ca 2 +/阳离子通道（ROCs），由G蛋白偶联受体（GPCR）通过Gq/11蛋白和磷脂酶C（PLC）刺激。由于大多数GPCR和ROC在包括神经元在内的可兴奋细胞中具有高得多的蛋白水平，为了维持细胞内Ca 2+稳态，这些细胞需要通过表达更多的调节分子来加强GPCR/ROC的调节机制。我们以前已经证明，dCAMTA，一个转录因子响应的Ca 2+传感器钙调蛋白，是必不可少的快速失活的光刺激GPCR视紫红质在果蝇的眼睛。dCAMTA属于一个新的转录因子家族，称为钙调素结合转录激活因子（CAMTA）。有趣的是，人类CAMTA，CAMTA 1和CAMTA 2，在大脑中高度表达。我们预测，钙调素/CAMTA刺激的基因表达可能会加强控制机制的GPCR/ROC介导的Ca 2+内流在神经元中，在一个长期的反馈方式。为了验证这一假设，我们建议使用dCAMTA作为模型，并利用苍蝇的光转导级联，一个典型的GPCR/PLC级联，已成功地用于识别的第一个ROC通道TRP。在这个项目中，我们将1。检验dCAMTA靶基因dFbxl 4对于视紫红质的快速失活是不可缺少的假设; 2.测试dFbxl 4与肌球蛋白III NINAC相互作用以使视紫红质失活的假设; 3.验证dCAMTA促进钙调素表达以促进视紫红质失活的假设; 4.测试dCAMTA的丢失导致老年果蝇中Ca 2+依赖性空泡感光细胞变性的假设; 5.鉴定dCAMTA和人CAMTA 1的核定位序列; 6.检验Fbxl 4和/或cam 1是人CAMTA 1的靶基因的假设。公共卫生相关性：钙稳态的缺陷与包括几种神经变性疾病在内的多种人类疾病有关（阿尔茨海默氏病和脊髓小脑共济失调）和几种形式的免疫缺陷这项研究的长期目标是充分了解细胞内Ca 2+是如何在细胞内形成的。在生理和病理条件下维持体内平衡，并使用该知识来促进这些人类疾病的治疗和可能的预防疾病本研究将研究一组新的转录因子如何以反馈方式调节Ca 2+稳态。