Iron and copper transporter trafficking in healthy and diseased melanocytes

健康和患病黑素细胞中铁和铜转运蛋白的运输

• 批准号: 7282640
• 负责人: Michael S Marks
• 金额: $ 13万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7282640
• 关键词: Address; Affect; Animal Model; Biological Models; Carrier Proteins; Cell Fractionation; Cell membrane; Cells; Cellular biology; Characteristics; Complex; Copper; Cytoplasm; Cytosol; Data; Defect; Development; Disease; Ensure; Environment; Enzymes; Extracellular Space; Failure; Goals; Hepatolenticular Degeneration; Hereditary Disease; Hermanski-Pudlak Syndrome; Immunofluorescence Microscopy; Intracellular Membranes; Ion Pumps; Ions; Iron; Laboratories; Link; Localized; Lysosomes; Mammalian Cell; Mammals; Melanins; Melanosomes; Menkes Kinky Hair Syndrome; Metabolism; Metalloproteins; Metals; Molecular; Monophenol Monooxygenase; Mus; Mutation; Organelles; Oxidation-Reduction; Pathway interactions; Phenotype; Pigmentation physiologic function; Pigments; Process; Property; Proteins; Pump; Research Personnel; Route; SLC11A2 gene; Sorting - Cell Movement; Testing; Thinking; Transferrin Receptor; Transition Elements; Transmembrane Transport; Variant; Wilson disease protein; Yeasts; cell type; cofactor; cohort; enzyme activity; extracellular; in vivo; intracellular protein transport; iron (III) reductase; melanocyte; metalloenzyme; mouse model; novel; programs; protein transport; response; secretory protein; trafficking; uptake

DESCRIPTION (provided by applicant): Copper and iron are cofactors for many cellular enzymes and transporters, but are also toxic redox-reactive transition metals. Their cellular levels are thus tightly controlled by specific transporters that import extracellular ion to the cytoplasm, and for copper by ATP-dependent pumps (ATP7A and ATP7B) that export copper from the cytosol to the secretory/endocytic pathway or outside the cell. ATP7A deficiency causes Menkes Disease, a severe developmental and systemic disorder of cytoplasmic copper accumulation and failure to load secretory cuproproteins. Neither the mechanisms by which copper is loaded from ATP7A into target cuproproteins nor those regulating the subcellular distribution of copper and iron transporters are understood. The ATP7A orthologue in yeast is needed to activate copper-dependent iron import; whether such a link between cellular copper and iron import exists in mammals is not known. This proposal exploits unique properties of melanocytes, in which copper is a cofactor for the melanin biosynthetic enzyme, tyrosinase, to dissect molecular mechanisms regulating copper and iron transporter localization and copper loading onto secretory proteins. Preliminary data suggest that an ATP7A cohort in melanocytes localizes to melanosomes dependent on its target cuproenzyme, tyrosinase, and on BLOC-1, a cytoplasmic complex defective in the vesicular transport disorder, Hermansky Pudlak Syndrome (HPS). Moreover, a copper-dependent ATP7A translocation defect and elevated transferrin receptor levels in HPS melanocytes suggest that BLOC-1 may regulate copper and iron import. Our unique expertise in HPS and melanocyte cell biology and our collaborator's expertise in iron and copper metabolism will be applied to the following Specific Aims: 1. To test the hypothesis that ATP7A localizes to melanosomes by associating with its substrate, tyrosinase. 2. To test the hypothesis that copper import is regulated by the HPS-associated BLOC-1 complex. 3. To test the hypothesis that iron import in melanocytes is regulated by BLOC-1 and by copper import. Summary: Menkes Disease is due to a genetic defect in iron and copper flux in many cell types, and Hermansky Pudlak Syndrome is an often lethal genetic disorder of only certain cell types, including pigment cells. This proposal tests the hypothesis that Hermansky Pudlak Syndrome results from iron and copper dysregulation in the affected cell types.

描述（由申请人提供）：铜和铁是许多细胞酶和转运蛋白的辅助因子，但也是有毒的氧化还原反应性过渡金属。因此，它们的细胞水平受到特定转运蛋白的严格控制，该转运蛋白将细胞外离子导入细胞质，而铜则受到 ATP 依赖性泵（ATP7A 和 ATP7B）的严格控制，这些泵将铜从细胞质转运到分泌/内吞途径或细胞外。 ATP7A 缺乏会导致门克斯病，这是一种细胞质铜积累和分泌性铜蛋白加载失败的严重发育和系统性疾病。铜从 ATP7A 加载到靶铜蛋白的机制以及调节铜和铁转运蛋白的亚细胞分布的机制均不清楚。酵母中的 ATP7A 直系同源物是激活铜依赖性铁输入所必需的；哺乳动物的细胞铜和铁输入之间是否存在这种联系尚不清楚。该提案利用了黑素细胞的独特特性，其中铜是黑色素生物合成酶酪氨酸酶的辅助因子，以剖析调节铜和铁转运蛋白定位以及铜负载到分泌蛋白上的分子机制。初步数据表明，黑素细胞中的 ATP7A 群体定位于黑素体，依赖于其靶标铜酶、酪氨酸酶和 BLOC-1（一种在囊泡运输障碍、赫曼斯基普德拉克综合征 (HPS) 中存在缺陷的细胞质复合物）。此外，HPS 黑素细胞中铜依赖性 ATP7A 易位缺陷和转铁蛋白受体水平升高表明 BLOC-1 可能调节铜和铁的输入。我们在 HPS 和黑素细胞生物学方面的独特专业知识以及我们合作者在铁和铜代谢方面的专业知识将应用于以下具体目标： 1. 检验 ATP7A 通过与其底物酪氨酸酶结合而定位于黑素体的假设。 2. 检验铜输入受 HPS 相关 BLOC-1 复合物调节的假设。 3. 检验黑素细胞中铁输入受BLOC-1 和铜输入调节的假设。摘要：门克斯病是由于许多细胞类型中铁和铜通量的遗传缺陷造成的，而赫曼斯基普德拉克综合征是一种通常仅对某些细胞类型（包括色素细胞）致命的遗传性疾病。该提案检验了赫曼斯基普德拉克综合征是由受影响细胞类型中铁和铜失调引起的假设。