Complementation and in vivo biochemical characterization of the Pneumocystis carinii MAPK.
Complementation and in vivo biochemical characterization of the Pneumocystis carinii MAPK.
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卡氏肺囊虫 MAPK 的互补和体内生化特征。
DOI：
10.1111/j.1550-7408.2003.tb00681.x
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
ThomasJr,CharlesF
中科院分区：
文献类型：
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作者：
Vohra,PawanK;ThomasJr,CharlesF
卡氏肺孢子虫的生命周期特征不明确，部分原因是无法有效培养这种肺部机会性真菌。从感染肺中获得的卡氏肺孢子虫的显微镜研究显示了两种主要的生命周期形式，营养型和包囊型[1-2]。从营养型到多核孢囊的转变的基础和调节事件尚不清楚。在密切相关的子囊菌酿酒酵母中，两个单倍体细胞之间的接合由导致减数分裂的促分裂原活化蛋白激酶（MAPK）级联调节[3-7]。我们以前在卡氏肺孢子虫中鉴定了一种MAPK（P. carinii MAPK {PCM}），类似于S.酿酒酵母FUS 3（在信息素信号传导中有活性的真菌MAPK）（8）。PCM在S.酿酒酵母补充了这些酵母中的MAPK信息素信号传导途径。此外，信号传导反应可以被U 0126抑制，其特异性地抑制MAPK的MEK活化。我们发现了最佳PCM激酶活性对pH、温度和二价阳离子浓度的独特要求。我们研究了卡氏肺孢子虫营养型和包囊中PCM mRNA的表达和激酶活性。
The P. carinii life cycle is poorly characterized, in part due to the inability to effectively culture this pulmonary opportunistic fungus. Microscopic investigations of P. carinii obtained from infected lungs demonstrates two predominant life cycle forms, the trophic form and the cyst form [1–2]. The events underlying and regulating the transition from trophic forms to the multinucleated cysts are unknown. In the closely related ascomycete Saccharomyces cerevisiae, conjugation between two haploid cells is regulated by a mitogen-activated protein kinase (MAPK) cascade leading to meiosis [3–7]. Likewise in pathogenic fungi and protozoans, this MAPK pathway has additional roles in pathogenicity.We had previously identified a MAPK in P. carinii (P. carinii MAPK {PCM}), similar to S. cerevisiae FUS3 (fungal MAPK active in pheromone signaling)(8). Expression of PCM in S. cerevisiae complements the MAPK pheromone signaling pathway in these yeasts. Further, the signaling response can be inhibited by U0126, which specifically inhibits MEK activation of MAPK. We discovered unique requirements of pH, temperature, and divalent cation concentration for optimal PCM kinase activity. We investigated PCM mRNA expression and kinase activity in P. carinii trophic forms and cysts.