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LIFE CYCLE REGULATION OF PNEUMOCYSTIS CARINII BY MAPK

MAPK 对卡氏肺囊虫生命周期的调控

基本信息

批准号：
6168734
负责人：
CHARLES FRANCIS THOMAS
金额：
$ 11.46万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-07-01 至 2001-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6168734
关键词：
Pneumocystis carinii biological signal transduction cell cycle cell differentiation cell growth regulation cell proliferation enzyme activity flow cytometry fungal genetics immunoelectron microscopy immunoprecipitation laboratory rat life cycle mitogen activated protein kinase northern blottings polymerase chain reaction transfection

项目摘要

Pneumocystis carinii is an opportunistic fungal pathogen which causes severe pneumonia in patients with an impaired immune system, particularly in patients with AIDS. The life cycle of P. carinii is poorly understood. In closely related fungi, Cdc2 associated with a regulatory cyclin controls the transition through the G1 restriction point START in the cell cycle.1-7 In fungi homologous to P. carinii, pheromone mating factors inhibit START through a mitogen-activated protein kinase (MAPK) signal transduction cascade which results in cell cycle arrest and cellular differentiation.8-14 MAPK phosphorylates an inhibitor of the Cdc2-cyclin complex.15-18 MAPK is the essential molecule in the pheromone mating cascade which controls the transition from mitotic growth to a pathway of conjugation, cellular differentiation, and proliferation.8 As an essential molecule regulating an organism's life cycle, MAPK is regulated by a kinase cascade and is activated by phosphorylation on two conserved threonine and tyrosine amino acids.19-24 Attachment of P. carinii to the alveolar epithelium is a central feature of P. carinii pneumonia, and binding to the epithelium is required for the organisms to proliferate.25-26 Our initial studies indicate that P. carinii possesses a MAPK which is highly homologous to fungal MAPK's involved in mating.27 We, therefore, hypothesize that the MAPK signal transduction cascade has a central role in the regulation of the P. carinii life cycle. We further propose that the P. carinii MAPK regulates cellular differentiation and proliferation of P. carinii organisms. To evaluate these hypotheses, we will undertake several parallel investigations. We will characterize the P. carinii MAPK genes involved in life cycle regulation. We will determine the kinase activity and the regulatory phosphorylations for P. carinii MAPK. Further, we will determine whether the expression and activity of P. carinii MAPK is differentially regulated throughout the life cycle of P. carinii by evaluating MAPK in separated cysts and trophozoites. Finally, we will determine the role of MAPK in the transition from one life form to another by evaluating the expression and activity of P. carinii MAPK before and after attachment to the alveolar epithelium and by overexpressing MAPK genes in separated life cycle forms of P. carinii. Through these investigations, we hope to gain important insights into the life cycle regulation of P. carinii.

卡氏肺孢子虫是一种机会致病真菌，免疫系统受损的患者中的严重肺炎，尤其是艾滋病患者。卡氏肺孢子虫的生命周期是不太了解。在密切相关的真菌中，Cdc 2与一种调节性细胞周期蛋白通过G1限制来控制过渡细胞周期的开始点。1 -7在与卡氏肺孢子虫同源的真菌中，信息素交配因子通过丝裂原激活的蛋白激酶（MAPK）信号转导级联，导致细胞 8 -14 MAPK磷酸化， Cdc 2-细胞周期蛋白复合物的抑制剂。信息素交配级联中的一种分子，它控制着从有丝分裂生长到接合途径，分化和增殖。8作为一种重要的分子调节生物体的生命周期，MAPK由激酶调节级联，并通过磷酸化两个保守的苏氨酸激活 19 -24卡氏肺孢子虫与肺泡的附着上皮是卡氏肺孢子虫肺炎的中心特征，上皮细胞是生物体增殖所必需的。最初的研究表明卡氏肺吸虫具有MAPK，与参与交配的真菌MAPK高度同源。因此，假设MAPK信号转导级联具有核心作用卡氏肺孢子虫生命周期的调节我们进一步建议，卡氏疟原虫MAPK调节细胞分化和增殖卡氏肺孢子虫为了评估这些假设，我们将进行多项平行调查。我们将描述P。卡氏疟原虫MAPK基因参与生活史调控。我们将确定卡氏肺孢子虫的激酶活性和调节磷酸化 MAPK。此外，我们将确定是否表达和活动卡氏肺孢子虫MAPK在整个生命周期中受到不同的调节通过评估分离的包囊和滋养体中的MAPK来鉴定卡氏肺吸虫。最后，我们将确定MAPK在从一个过渡中的作用。通过评价P. 卡氏原丝裂原活化蛋白激酶在附着到肺泡上皮细胞之前和之后，通过在分离的P. carinii。通过这些调查，我们希望获得重要的卡氏肺孢子虫的生命周期调控。