Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA.
Institute for Systems Biology, Seattle, Washington, USA.
mBio. 2021 Dec 21;12(6):e0257521. doi: 10.1128/mBio.02575-21. Epub 2021 Nov 2.
Gametocytes of the malaria parasite are taken up by the mosquito vector with an infectious blood meal, representing a critical stage for parasite transmission. Calcium-independent protein kinases (CDPKs) play key roles in calcium-mediated signaling across the complex life cycle of the parasite. We sought to understand their role in human parasite transmission from the host to the mosquito vector and thus investigated the role of the human-infective parasite Plasmodium falciparum CDPK4 in the parasite life cycle. P. falciparum parasites created by targeted gene deletion showed no effect in blood stage development or gametocyte development. However, parasites showed a severe defect in male gametogenesis and the emergence of flagellated male gametes. To understand the molecular underpinnings of this defect, we performed mass spectrometry-based phosphoproteomic analyses of wild-type and Plasmodium falciparum late gametocyte stages to identify key CDPK4-mediated phosphorylation events that may be important for the regulation of male gametogenesis. We further employed assays to identify these putative substrates of Plasmodium falciparum CDPK4. This indicated that CDPK4 regulates male gametogenesis by directly or indirectly controlling key essential events, such as DNA replication, mRNA translation, and cell motility. Taken together, our work demonstrates that PfCDPK4 is a central kinase that regulates exflagellation and thereby is critical for parasite transmission to the mosquito vector. Transmission of the malaria parasite to the mosquito vector is critical for the completion of the sexual stage of the parasite life cycle and is dependent on the release of male gametes from the gametocyte body inside the mosquito midgut. In the present study, we demonstrate that PfCDPK4 is critical for male gametogenesis and is involved in phosphorylation of proteins essential for male gamete emergence. Targeting PfCDPK4 and its substrates may provide insights into achieving effective malaria transmission-blocking strategies.
疟原虫的配子体通过具有感染性的血餐被蚊子媒介吸收，这代表了寄生虫传播的关键阶段。钙非依赖性蛋白激酶（CDPKs）在寄生虫复杂生命周期中的钙介导信号转导中发挥关键作用。我们试图了解它们在寄生虫从宿主向蚊子媒介传播中的作用，因此研究了人类感染性寄生虫恶性疟原虫 CDPK4 在寄生虫生命周期中的作用。通过靶向基因缺失创建的恶性疟原虫寄生虫在血液阶段发育或配子体发育中没有影响。然而，寄生虫在雄性配子发生和有鞭毛的雄性配子出现方面出现严重缺陷。为了了解这种缺陷的分子基础，我们对野生型和恶性疟原虫晚期配子体阶段进行了基于质谱的磷酸化蛋白质组学分析，以鉴定可能对雄性配子发生调控很重要的关键 CDPK4 介导的磷酸化事件。我们进一步采用 测定法来鉴定这些恶性疟原虫 CDPK4 的假定底物。这表明 CDPK4 通过直接或间接控制关键的必要事件，例如 DNA 复制、mRNA 翻译和细胞运动，来调节雄性配子发生。总之，我们的工作表明 PfCDPK4 是一种调节出芽的关键激酶，对于寄生虫向蚊子媒介的传播至关重要。寄生虫向蚊子媒介的传播对于完成寄生虫生命周期的有性阶段至关重要，并且依赖于从蚊子中肠内的配子体体中释放雄性配子。在本研究中，我们证明 PfCDPK4 对于雄性配子发生至关重要，并参与了对雄性配子出现至关重要的蛋白质的磷酸化。针对 PfCDPK4 及其底物可能为实现有效的疟疾传播阻断策略提供思路。
