Membrane Protein Transport in Photoreceptors

光感受器中的膜蛋白转运

• 批准号: 8895945
• 负责人: WOLFGANG BAEHR
• 金额: $ 36.51万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-12-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8895945
• 关键词: Address; Adenylate Cyclase; Affect; Alleles; Animals; Antibodies; Binding; Binding Proteins; Brain; Calcium-Binding Proteins; Calmodulin; Cell Culture Techniques; Cell Line; Cell Nucleus; Cell membrane; Cells; Cellular biology; Choroideremia; Cilia; Cilium Microtubule; Complex; Defect; Disease; Docking; Dominant-Negative Mutation; Drosophila genus; Dysosmia; EF Hand Motifs; Etiology; Exhibits; Family; Golf; Golgi Apparatus; Green Algae; Guanosine Triphosphate Phosphohydrolases; Guanylate Cyclase; Health; Human; Hydrocephalus; In Vitro; Integral Membrane Protein; Joubert syndrome; Knock-out; Knockout Mice; Life; Male Infertility; Mammalian Cell; Membrane; Membrane Protein Traffic; Membrane Proteins; Membrane Transport Proteins; MicroRNAs; Microtubule-Organizing Center; Microtubules; Modeling; Mus; Opsin; Pathway interactions; Patients; Phenotype; Photons; Photoreceptors; Phototransduction; Plants; Process; Protein Isoforms; Proteins; Regulation; Research; Retinal Degeneration; Retinal Diseases; Retinitis Pigmentosa; Rhodopsin; Ribosomes; Role; Site; Situs Inversus; Spermiogenesis; Structure; Syndrome; Tail; Tamoxifen; Technology; Testing; Transducin; Trimethoprim-Sulfamethoxazole; Vesicle; Vesicle Transport Pathway; Virus; Xenopus; analog; base; ciliopathy; cilium biogenesis; gene replacement therapy; gene therapy; human disease; immortalized cell; kinetosome; member; mouse model; mutant; olfactory sensory neurons; peripherin; photoreceptor degeneration; polypeptide; protein transport; research study; retinal rods; small hairpin RNA; sperm cell; trafficking; trans-Golgi Network; vector

DESCRIPTION (provided by applicant): Photoreceptor outer segment membranes, the site of initial photon capture initiating phototransduction, undergo renewal with total replacement occurring at ten day intervals throughout life. A challenge to cellular integrity concerns the post biosynthetic delivery of replacement proteins from the inner, to the outer, segment over the lifetime of the photoreceptor. Complex trafficking pathways require multiple components, such as acyl-binding proteins, Rab GTPases and centrins. This application will identify: i) key Rab GTPases involved in vesicular transport of membrane protein, and ii) centrins participating in ciliary transport. Aim 1 will focus on Rab GTPases in photoreceptor vesicular transport. Rab (Ras analog in brain) proteins are members of the Ras supergene family involved mainly in membrane protein trafficking. More than 70 distinct Rab polypeptides have been identified. Aim 1a focuses on Rab8 and Rab11 isoforms which are known to be important for photoreceptor trafficking in Xenopus and Drosophila models. Surprisingly, a mouse Rab8a/Rab11a double knockout does not produce a defective trafficking phenotype. Therefore, we will focus on closely-related isoforms to identify key Rab proteins responsible for membrane protein organization and rhodopsin trafficking. Aim 1b investigates Rab28, shown recently associated with recessive human cone/rod dystrophy. Aim 2 will examine the function of centrosomal proteins, called "centrins," which are 20kD EF- hand calcium binding proteins (four EF-hand motifs) of the calmodulin superfamily. Centrins were first described in unicellular green algae where they are associated with the flagellar basal apparatus. Photoreceptor centrins (isoforms 1-4) are located in the ciliary lumen and basal body where they associate with transducin via its Tßγ-subunits. One hypothesis is that centrins may be involved in regulation of transducin translocation from the outer, to the inner, segment or vice-versa. As preliminary results, we found that centrin1 is required for the nucleus-basal body connection during mouse spermiogenesis, and centrin2 regulates trafficking of ACIII and channel subunits in olfactory sensory neurons. This aim seeks to identify the roles of photoreceptor centrin3 and centrin4 which associate strongly with the basal body and/or connecting cilium axoneme. We expect to generate mouse models of syndromic disease with retina degeneration, e.g., Joubert or Senior-Loken syndromes.

描述（由申请人提供）：光感受器外节膜，即初始光子捕获启动光转导的部位，在整个生命周期中以十天的间隔进行一次完全更换。对细胞完整性的挑战涉及该帖子 在光感受器的整个生命周期内，将替代蛋白从内部片段生物合成传递到外部片段。复杂的运输途径需要多种成分，例如酰基结合蛋白、Rab GTP 酶和中心蛋白。该应用将鉴定：i) 参与膜蛋白囊泡转运的关键 Rab GTPases，以及 ii) 参与纤毛转运的中心蛋白。目标 1 将重点关注光感受器囊泡运输中的 Rab GTPases。 Rab（大脑中的 Ras 类似物）蛋白是 Ras 超基因家族的成员，主要参与膜蛋白运输。已鉴定出 70 多种不同的 Rab 多肽。目标 1a 重点关注 Rab8 和 Rab11 同工型，已知它们对于非洲爪蟾和果蝇模型中的光感受器运输非常重要。令人惊讶的是，小鼠 Rab8a/Rab11a 双敲除不会产生有缺陷的运输表型。因此，我们将重点关注密切相关的异构体，以确定负责膜蛋白组织和视紫红质运输的关键 Rab 蛋白。目标 1b 研究 Rab28，最近发现它与隐性人类视锥细胞/视杆细胞营养不良有关。目标 2 将检查中心体蛋白（称为“中心蛋白”）的功能，它们是钙调蛋白超家族的 20kD EF-手钙结合蛋白（四个 EF-手基序）。中心蛋白首次在单细胞绿藻中被描述，它们与鞭毛基底器相关。光感受器中心蛋白（亚型 1-4）位于睫状腔和基底体中，它们通过其 Tßγ 亚基与转导蛋白结合。一种假设是中心蛋白可能参与调节转导蛋白从外节段到内节段的易位，反之亦然。初步结果表明，centrin1 是小鼠精子发生过程中核-基底体连接所必需的，而 centrin2 则调节嗅觉感觉神经元中 ACIII 和通道亚基的运输。该目的旨在确定与基体和/或连接纤毛轴丝密切相关的光感受器 centrin3 和 centrin4 的作用。我们期望建立视网膜变性综合征疾病的小鼠模型，例如 Joubert 或 Senior-Loken 综合征。