Mechanism of amyloid formation during melanosome biogenesis

黑素体生物发生过程中淀粉样蛋白形成的机制

• 批准号: 9262141
• 负责人: Ralf Max Leonhardt
• 金额: $ 22.11万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9262141
• 关键词: Address; Alzheimer' s Disease; Amyloid; Behavior; Biochemical; Biogenesis; Biological Assay; Biological Models; Biology; Cell Line; Cells; Characteristics; Circular Dichroism Spectroscopy; Complement; Complex; Confocal Microscopy; Data; Deposition; Diabetes Mellitus; Diffuse; Dimerization; Disease; Dominant-Negative Mutation; Early Endosome; Electron Microscopy; Employee Strikes; Endosomes; Engineering; Environment; Fluorescence; Goals; Hair; Human; Life; Link; Malignant Neoplasms; Melanins; Melanoma Cell; Melanosomes; Membrane Proteins; Microscopy; Molecular; Molecular Conformation; Molecular Sieve Chromatography; Mutate; N-terminal; Organelles; Parkinson Disease; Pathologic; Pathway interactions; Peptides; Physiological; Pigmentation Disorders; Pigmentation physiologic function; Pigments; Play; Prion Diseases; Process; Proteins; Proteolytic Processing; Reaction; Recycling; Role; Side; Skin; Skin Cancer; Small Interfering RNA; Spidroins; Structure; System; Techniques; Time; Toxic effect; Tryptophan; Work; amyloid formation; beta pleated sheet; cellular imaging; dimer; experimental study; in vivo; interest; melanocyte; melanoma; mutant; novel; public health relevance; rab GTP-Binding Proteins; response; trafficking; transcriptome sequencing; ultraviolet irradiation

 DESCRIPTION (provided by applicant): PMEL is a key factor in melanocytes and operates in the pigmentation pathway that protects our skin from skin cancer. To this end, the protein forms a physiological amyloid matrix in melanosomes. This matrix serves for the deposition of the pigment melanin, which shields our skin against hazardous UV irradiation. PMEL was the first physiological amyloid to be discovered in human cells. It is a cousin of the more (in) famous pathological, toxic amyloids linked with various incurable diseases, such as Alzheimer's and Parkinson's Disease, prion diseases, diabetes, and cancer. However, physiological amyloids like PMEL share various aspects and certain pathways of formation with their pathological counterparts and some assemble and/or accumulate in similar endocytic compartments. Thus, PMEL is an attractive model system to study amyloids and additionally holds the promise of revealing fundamental secrets of melanocyte and pigmentation biology. While PMEL behaves like a conventional membrane protein in early secretory compartments, it unleashes a massive potential for aggregation once it arrives in the melanosome. We aim to examine how the molecule senses the specific melanosomal environment, to characterize the structural transitions of the molecule in response to this environment, and to investigate how the process is regulated. Additionally, we seek to understand how PMEL manages to assemble into amyloid without developing the toxicity for which amyloids are notorious. Finally, we propose to characterize the molecular and cellular requirements for PMEL amyloid formation focusing on the role of Rab GTPases and their effectors in the process. In the context of our preliminary results, we already identified one particular Rab GTPase whose function appears to be required for proper PMEL processing and we will investigate how it works. Our search for cellular factors promoting amyloid formation may discover key molecules involved in establishing the identity of early melanosomes, the organelles that provide the optimal environment for PMEL to form fibrous amyloid. Our specific aims are (1) Characterizing how the functional interplay of the PMEL domains drives amyloid formation and (2) Identifying molecular & cellular requirements for amyloid formation.

 描述(申请人提供)：PMEL是黑素细胞中的关键因子，在保护我们的皮肤免受皮肤癌侵袭的色素沉积途径中发挥作用。为此，这种蛋白质在黑素小体中形成了一种生理性的淀粉样基质。这种基质用于色素黑色素的沉积，保护我们的皮肤免受有害的紫外线照射。PMEL是第一个在人类细胞中发现的生理性淀粉样蛋白。它是更著名的病理性有毒淀粉样蛋白的近亲，它与各种不治之症有关，如阿尔茨海默氏症、帕金森氏病、普里恩病、糖尿病和癌症。然而，生理淀粉样蛋白，如PMEL，与病理性淀粉样蛋白在不同方面和某些形成途径相同，有些在相似的内吞体内聚集和/或积累。因此，PMEL是一个有吸引力的研究淀粉样蛋白的模型系统，并有望揭示黑素细胞和色素沉积生物学的基本秘密。虽然PMEL在早期分泌间隔中的行为类似于传统的膜蛋白，但一旦到达黑小体，它就会释放出巨大的聚集潜力。我们的目标是研究分子如何感知特定的黑素体环境，表征分子对这种环境的结构转变，并研究这一过程是如何调节的。此外，我们试图了解PMEL是如何在不发展淀粉样蛋白臭名昭著的毒性的情况下组装成淀粉样蛋白的。最后，我们建议表征PMEL淀粉样蛋白形成的分子和细胞需求，重点是Rab GTP酶及其效应因子在这一过程中的作用。在我们的初步结果的背景下，我们已经确定了一个特定的Rab GTP酶，其功能似乎是正确的PMEL处理所必需的，我们将研究它是如何发挥作用的。我们对促进淀粉样蛋白形成的细胞因子的研究可能会发现参与确定早期黑素小体身份的关键分子，这些细胞器为PMEL提供形成纤维淀粉样蛋白的最佳环境。我们的具体目标是(1)描述PMEL结构域的功能相互作用如何驱动淀粉样蛋白的形成，以及(2)确定淀粉样蛋白形成的分子和细胞需求。

项目成果

Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL.

• DOI: 10.1038/s41598-021-87259-y
• 发表时间: 2021-04-08
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Mitchell SM;Graham M;Liu X;Leonhardt RM
• 通讯作者: Leonhardt RM