Molecular mechanisms of a gamete membrane fusion reaction during fertilization

受精过程中配子膜融合反应的分子机制

• 批准号: 9906045
• 负责人: Jennifer Fricke Pinello
• 金额: $ 6.53万
• 依托单位: UNIV OF MARYLAND, COLLEGE PARK
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-03 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9906045
• 关键词: Adhesions; Algae; Angiosperms; Animals; Appearance; Arabidopsis; Arthropods; Binding; Binding Proteins; Biochemical; Biological Models; Cell Adhesion Molecules; Cell fusion; Cell membrane; Cells; Charge; Chimeric Proteins; Chlamydomonas; Chlamydomonas reinhardtii; Clinical; Cryptosporidium; Cysteine; Cytoplasmic Tail; Data; Dengue; Disulfides; Eimeria; Event; Family; Fertilization; Genes; Germ Cells; Green Algae; Hantavirus; Health; Human; Huntingtin-Associated protein 1; Hydrophobicity; Infection; Knowledge; Laboratories; Lead; Life; Life Cycle Stages; Lipid Bilayers; Malaria; Mediating; Membrane; Membrane Fusion; Membrane Proteins; Methods; Modeling; Molecular; Molecular Conformation; Mus; Mutation; Organism; Orthologous Gene; PDAP2 Gene; Parasites; Parasitic Diseases; Partner in relationship; Pathway interactions; Plants; Plasmodium; Prevention strategy; Property; Proteins; Publishing; Reaction; Reproduction; Reproductive Process; Research; Role; Site; Structure; Testing; Tetrahymena; Threonine; Toxoplasma; Trypanosoma; Vaccines; Vertebrates; Viral; Viral Proteins; Virus; Work; ZIKA; base; crosslink; design; dimer; egg; experimental study; improved; male; monomer; mutant; pathogen; protein function; protein structure; receptor binding; response; sex; sperm cell; therapeutic target; transmission process

Project Summary Membrane fusion between gametes (e.g. sperm & egg) during fertilization is a crucial step in eukaryotic life cycles. Unfortunately, not much is known about the molecules regulating this vital reproductive process. One protein that is known to be important is HAP2, a conserved, male-gamete- specific factor necessary for fertilization in a wide range of eukaryotic species, including many important human and animal pathogens (e.g. Plasmodium sp. causing malaria, Trypanosoma, Toxoplasma, Eimeria, etc.). Exciting recent work has discovered that HAP2 is structurally homologous to viral class II fusion proteins. These viral (e.g. Dengue and Zika) class II proteins mediate the merger of virus and host cell membranes during infection and are dependent upon oligomeric and conformational changes in response to low pH for their fusogenic activity. The proposed studies will test the model that, before fusion, HAP2 organizes itself on the gamete membrane in a similar way to certain viral class II proteins, which in turn, helps regulate HAP2's function in gamete cell fusion during sex. The experimentally- amenable sexual life cycle of the unicellular micro-alga, Chlamydomonas reinhardtii, will be used as a model system. Genetically-tractable Chlamydomonas cells readily form plus and minus gametes in the laboratory and well-established methods exist for quantifying the distinct steps in the gamete membrane fusion reaction. Chlamydomonas is also the only organism in which a HAP2 protein structure has been published and where a receptor-binding protein which interacts with HAP2 has been identified (MAR1, preliminary data). Furthermore, using strategically designed mutations of Chlamydomonas HAP2, along with biochemical crosslinking methods, we have detected oligomeric forms of this fusogen which offer tantalizing clues concerning its multimeric contacts on the membrane before fusion. The long-term objectives of this proposal are to enhance our fundamental understanding of the mechanism of membrane fusion at fertilization and to identify additional therapeutic targets on HAP2 which could lead to better vaccines or prevention strategies for many harmful parasitic diseases.

项目摘要 受精过程中配子(如精子和卵子)之间的膜融合是 真核生物的生命周期。不幸的是，人们对调节这一至关重要的分子知之甚少。 生殖过程。已知的一种重要蛋白质是HAP2，一种保守的雄配子- 在广泛的真核物种中受精所需的特定因子，包括许多 重要的人和动物病原体(如疟原虫sp.导致疟疾、锥虫、弓形虫、 艾美耳球虫等)。令人兴奋的最新研究发现，HAP2在结构上与II类病毒同源 融合蛋白。这些病毒(如登革热和寨卡病毒)II类蛋白介导病毒和 感染过程中的宿主细胞膜，依赖于寡聚体和构象的变化 以响应低pH的融合活性。拟议的研究将测试该模型，在此之前 融合，HAP2以类似于某些病毒II类蛋白的方式在配子膜上组织自己， 这反过来又有助于调节HAP2的S在性行为过程中配子细胞融合的功能。从实验上讲- 单细胞微藻--莱茵衣藻的性生活周期将被用作 模型系统。遗传上易驯化的衣藻细胞在体内容易形成正负配子 已经有实验室和成熟的方法来量化配子中的不同步骤 膜融合反应。衣藻也是唯一一种具有HAP2蛋白结构的生物 已经发表，与HAP2相互作用的受体结合蛋白已经在 已确定(MaR1，初步数据)。此外，使用战略设计的突变 衣藻HAP2，结合生化交联法，我们检测到了寡聚体 这种FusoGen的形态，为其在膜上的多聚体接触提供了诱人的线索 在核聚变之前。这项建议的长期目标是增进我们对 受精时膜融合的机制及寻找新的治疗靶点 HAP2，这可能导致针对许多有害寄生虫病的更好的疫苗或预防策略。