Pheromone Signaling in Pneumocystis Carinii

描述（由申请人提供）：卡氏肺孢子虫是一种机会性 真菌病原体导致严重肺炎的患者受损 免疫力低下，如艾滋病患者。卡氏肺孢子虫的生活史 明白在与卡氏肺孢子虫相关的真菌中，营养缺乏和 干燥是交配因子释放的主要刺激 其激活促分裂原活化蛋白激酶（MAPK），导致有丝分裂。 细胞周期阻滞、接合和减数分裂，以及致病性增加。MAPK 是信息素诱导的信号转导级联反应中的重要分子 控制着这些事件作为一种重要的分子， 在生命周期中，MAPK活性受到高度调节。双磷酸化是 需要激活，可变的MAPK活性和表达是 仅限于某些生命周期形式。我们的初步研究表明，P。 carinii具有与真菌信息素诱导的 MAPKs我们假设信息素诱导的丝裂原活化蛋白 MAPK信号转导级联调控细胞分化 以及卡氏肺孢子虫生物体的增殖。作为一个重要组成部分， 真菌的生命周期，卡氏疟原虫MAPK的研究将导致 加强对卡氏肺孢子虫生命周期、致病性和导致 开发治疗卡氏肺孢子虫肺炎的新型治疗剂。到 评估这些假设，我们将进行几个平行的调查。 分离的生命周期形式中的MAPK活性和表达将被访问， 确定卡氏肺孢子虫MAPK是否相对于卡氏肺孢子虫受到差异调节。 卡氏虫生活史我们将鉴定并描述卡氏疟原虫信息素 受体和单独的卡氏肺孢子虫交配型。我们将访问是否 营养缺乏、缺氧或温度变化导致有丝分裂细胞 周期停滞导致减数分裂和囊肿的形成，以及是否 MAPK级联的抑制剂阻断这些作用。我们还将调查， 分离的交配型进行单倍体有丝分裂，或者如果交配型的混合， 对于减数分裂和包囊的形成至关重要。通过这些调查， 我们希望获得对生命周期监管的重要见解， 致病性P. carinii。

DESCRIPTION (provided by applicant): Pneumocystis carinii is an opportunistic fungal pathogen which causes severe pneumonia in patients with impaired immunity such as patients with AIDS. The life cycle of P. carinii is poorly understood. In fungi related to P. carinii, nutrient deprivation and dessication are the major stimuli for the release of pheromone mating factors which activate a mitogen-activated protein kinase (MAPK), resulting in mitotic cell cycle arrest, conjugation and meiosis, and increased pathogenicity. MAPK is the essential molecule in the pheromone-induced signal transduction cascade which controls these events. As an essential molecule regulating an organism's life cycle, MAPK activity is highly regulated. Dual phosphorylations are requiring for activation, and variable MAPK activity and expression are restricted to certain life cycle forms. Our initial studies indicate that P. carinii possesses a MAPK which is closely related to fungal pheromone-induced MAPKs. We hypothesize that the pheromone-induced mitogen-activated protein kinase (MAPK) signal transduction cascade regulates cellular differentiation and proliferation of P. carinii organisms. As an essential component in the life cycle of fungi, investigation of the P. carinii MAPK will result in an enhanced understanding of the P. carinii life cycle, pathogenicity, and lead to development of novel therapeutic agents to treat P. carinii pneumonia. To evaluate these hypotheses, we will undertake several parallel investigations. MAPK activity and expression in separated life cycle forms will be accessed to determine whether P. carinii MAPK is differentially regulated over the P. carinii life cycle. We will identify and characterize the P. carinii pheromone receptors and separate P. carinii mating types by FACS. We will access whether nutrient deprivation, hypoxia, or temperature changes results in mitotic cell cycle arrest leading to meiosis and formation of the cyst, and whether inhibitors of the MAPK cascade block these effects. We will also investigate if isolated mating types undergo haploid mitosis or if mixing of mating types is essential for meiosis and formation of the cyst. Through these investigations, we hope to gain important insights into the life cycle regulation and pathogenicity ofP. carinii.