The Malaria Parasite Cyclic GMP-Dependent Protein Kinase Plays a Central Role in Blood-Stage Schizogony
The Malaria Parasite Cyclic GMP-Dependent Protein Kinase Plays a Central Role in Blood-Stage Schizogony
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DOI：
10.1128/ec.00186-09
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发表时间：
2010-01-01
期刊：
影响因子：
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通讯作者：
Baker, David A.
中科院分区：
文献类型：
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作者：
Taylor, Helen M.;McRobert, Louisa;Baker, David A.
恶性疟原虫环GMP（cGMP）依赖性蛋白激酶（PfPKG）在疟疾寄生虫配子发生中的作用以前已阐明。在本研究中，我们研究了PfPKG在寄生虫生命周期的无性血液阶段中的作用，该阶段导致疟疾病理学。特异性PKG抑制剂（化合物1，三取代吡咯）在红细胞侵入测定中阻止恶性疟原虫疟原虫幼虫进展至环状阶段。此外，化合物1的环阶段的寄生虫允许正常发展到30小时postinvasion，和分段的寄生虫能够形成。然而，用化合物1处理>= 6小时的同步化裂殖子变得大且畸形，并且不能破裂或释放裂殖子。为了最终证明化合物1对疟原虫生殖的影响是由于其对PfPKG的选择性作用，我们利用了表达化合物1不敏感的PfPKG的遗传操作的恶性疟原虫寄生虫。突变体寄生虫能够在化合物1的存在下而不是在广谱蛋白激酶抑制剂staurosporine的存在下完成寄生生殖。这表明PfPKG是化合物1在胚胎发育过程中的主要靶标，并提供了PfPKG在该过程中的作用的直接证据。恶性疟原虫PKG在无性和性发育中的重要作用的发现表明，cGMP信号传导是这两个关键生命周期阶段的关键调节剂，并将该分子定义为针对疟疾的治疗和传播阻断作用的令人兴奋的潜在药物靶标。
A role for the Plasmodium falciparum cyclic GMP (cGMP)-dependent protein kinase (PfPKG) in gametogenesis in the malaria parasite was elucidated previously. In the present study we examined the role of PfPKG in the asexual blood-stage of the parasite life cycle, the stage that causes malaria pathology. A specific PKG inhibitor (compound 1, a trisubstituted pyrrole) prevented the progression of P. falciparum schizonts through to ring stages in erythrocyte invasion assays. Addition of compound 1 to ring-stage parasites allowed normal development up to 30 h postinvasion, and segmented schizonts were able to form. However, synchronized schizonts treated with compound 1 for >= 6 h became large and dysmorphic and were unable to rupture or liberate merozoites. To conclusively demonstrate that the effect of compound 1 on schizogony was due to its selective action on PfPKG, we utilized genetically manipulated P. falciparum parasites expressing a compound 1-insensitive PfPKG. The mutant parasites were able to complete schizogony in the presence of compound 1 but not in the presence of the broad-spectrum protein kinase inhibitor staurosporine. This shows that PfPKG is the primary target of compound 1 during schizogony and provides direct evidence of a role for PfPKG in this process. Discovery of essential roles for the P. falciparum PKG in both asexual and sexual development demonstrates that cGMP signaling is a key regulator of both of these crucial life cycle phases and defines this molecule as an exciting potential drug target for both therapeutic and transmission blocking action against malaria.