Probing intercellular GPCR-GPCR ineractions in fungal cell fusion events

探讨真菌细胞融合事件中的细胞间 GPCR-GPCR 缺失

• 批准号: 261683-2006
• 负责人: Loewen, Michele
• 金额: $ 2.62万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=337102
• 关键词: Probing; intercellular; GPCR; ineractions; fungal

Ste2p and Ste3p are well characterized Class D yeast pheromone (alpha- and a- factor respectively) G-protein coupled receptors (GPCRs) involved in signaling of mating responses that lead to cell fusion.  Their interactions with downstream signal transduction machinery are well established and homologous to those in mammalian GPCR systems, which comprise the vast majority of pharmaceutical targets at this time. We recently detected and characterized a ligand-dependent, intercellular interaction between the yeast mating G-protein coupled receptors Ste2p and Ste3p through applications of tandem affinity purification and surface plasmon resonance methods. Cellular pull-down assays demonstrated the extracellular domain-mediated nature of the interaction and in vivo analyses indicated receptor-dependent increases in cell-cell interactions.  Consideration of these results in the context of the natural localization of Ste2p and Ste3p on the surfaces of opposite mating cell types suggests the possibility of an additional role for these receptors as the fusogens, involved in physically bringing the MATa and MATalpha cell membranes together. Cell-cell fusion is a widespread event which occurs during a variety of physiologically relevant processes including epidermal cell fusion, myoblast fusion, fertilization, trophoblast fusion in the placenta, macrophage fusion and stem cell fusion.  Although this type of intercellular heteromeric GPCR interaction has never before been detected, based on the wide spread occurrence of GPCRs it may impact on many of these other areas of cell fusion research for which fusogens remain as yet unidentified.  It may also be relevant to other GPCR systems such as neuronal signaling where a myriad of GPCRs are known to be expressed at neural junctions.  GPCR-GPCR intercellular interactions may represent an entirely new level of signaling regulation across the pharmaceutically important GPCR superfamily. This research program is concerned with the continued characterization of this important interaction.

Ste 2 p和Ste 3 p是D类酵母信息素（分别为α因子和α因子）G蛋白偶联受体（GPCR），它们与下游信号转导机制的相互作用已得到充分证实，并与哺乳动物GPCR系统中的相互作用具有同源性，哺乳动物GPCR系统目前构成了绝大多数药物靶标。我们最近检测和表征的配体依赖性，酵母交配G-蛋白偶联受体之间的相互作用的STE 2 P和STE 3 P通过串联亲和纯化和表面等离子体共振方法的应用。细胞下拉分析证明了细胞外结构域介导的相互作用的性质，体内分析表明细胞-细胞相互作用的受体依赖性增加。考虑到Ste 2 p和Ste 3 p在相反交配细胞类型表面上的天然定位，这些结果表明这些受体作为融合子的额外作用的可能性，参与将MAT α和MAT α细胞膜物理地结合在一起。细胞-细胞融合是一种广泛存在的生物学过程，包括表皮细胞融合、成肌细胞融合、受精、胎盘滋养层细胞融合、巨噬细胞融合和干细胞融合等。基于GPCR的广泛存在，它可能会影响到细胞融合研究的许多其他领域，这些领域的融合子仍然没有确定。GPCR-GPCR细胞间相互作用可以代表跨药学上重要的GPCR超家族的全新水平的信号调节。本研究计划关注的是这种重要相互作用的持续表征。