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 施肥期间配子（例如精子和鸡蛋）之间的膜融合是至关重要的一步。 真核生物生命周期。不幸的是，对调节这一重要的分子知之甚少 生殖过程。一种已知重要的蛋白质是HAP2，一种保守的，男性的蛋白质 在多种真核物种中受精所必需的特定因素，包括许多 重要的人类和动物病原体（例如疟原虫引起疟疾，锥虫，毒质量，弓形虫， Eimeria等）。令人兴奋的最近工作发现HAP2在结构上与病毒II类同源 融合蛋白。这些病毒（例如登革热和寨卡病毒）II类蛋白介导病毒的合并和 感染过程中的宿主细胞膜，依赖于寡聚和构象变化 响应低pH的融合活性。拟议的研究将测试在之前的模型 融合，HAP2以与某些病毒II类蛋白相似的方式在配子膜上组织自己 反过来，这有助于调节性爱过程中HAP2在配子细胞融合中的功能。实验 - 单细胞微α的性行为生命周期，Chlamydomonas Reinhardtii将被用作 模型系统。在基因上牵引的衣原体细胞很容易形成和减去配子 存在实验室和公认的方法来量化配子中的不同步骤 膜融合反应。衣原体也是HAP2蛋白结构的唯一生物 已经发表了与HAP2相互作用的受体结合蛋白的发表 确定（MAR1，初步数据）。此外，使用战略性设计的突变 衣原体HAP2，以及生化交联方法，我们检测到了低聚 这种熔融的形式提供了有关其多聚体接触的诱人线索 融合之前。该提案的长期目标是增进我们的基本理解 在受精时膜融合机理的机理，并确定有关额外的治疗靶标 HAP2可能会导致许多有害寄生疾病的更好的疫苗或预防策略。