A novel Plasmodium yoelii pseudokinase, PypPK1, is involved in erythrocyte invasion and exflagellation center formation
A novel Plasmodium yoelii pseudokinase, PypPK1, is involved in erythrocyte invasion and exflagellation center formation
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一种新型约氏疟原虫假激酶 PypPK1 参与红细胞侵袭和去鞭毛中心形成
DOI：
10.1016/j.parint.2020.102056
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发表时间：
2020
影响因子：
1.9
通讯作者：
Kaneko Osamu
中科院分区：
文献类型：
--
作者：
Ishizaki Takahiro;Chaiyawong Nattawat;Hakimi Hassan;Asada Masahito;Tachibana Mayumi;Ishino Tomoko;Yahata Kazuhide;Kaneko Osamu
在脊椎动物宿主中，疟疾寄生虫通过反复入侵和在红细胞内繁殖而繁殖。有性行为的红细胞内寄生虫经历有性阶段的分化，成为配子体。蚊子摄取后，雄性和雌性配子体从红细胞中排出，在蚊子中肠内受精。一条复杂的信号通路可能会对环境事件做出反应，以触发配子发生和调节受精；然而，对于疟疾寄生虫来说，这样的知识仍然有限。一些假蛋白激酶在配子体阶段高度转录，可能是控制生命周期关键步骤的多功能调节因子。在这里，我们描述了约氏疟原虫中一种在裂殖体和雄配子细胞中高表达的伪激酶，称为PypPK1。对表达Myc标记的PypPK1的寄生虫的免疫荧光检测证实，PypPK1蛋白在裂殖体和有性期寄生虫中都有表达。用CRISPR/CAS9方法缺失Δ基因位点的转基因PypPK1ppk1寄生虫在小鼠体内表现出明显的生长缺陷和毒力降低。在血液期，Δppk1寄生虫与野生型寄生虫相似，能够从红细胞中排出，但红细胞侵袭能力显著降低。在有性发育阶段，Δppk1寄生虫的雄、雌性配子体和配子体从红细胞中流出的数量没有明显变化，但外露中心和卵囊的数量显著减少。综上所述，PypPK1对红细胞的侵袭和出毛中心的形成都具有重要作用。
Malaria parasites proliferate by repeated invasion of and multiplication within erythrocytes in the vertebrate host. Sexually committed intraerythrocytic parasites undergo sexual stage differentiation to become gametocytes. After ingestion by the mosquito, male and female gametocytes egress from erythrocytes and fertilize within the mosquito midgut. A complex signaling pathway likely responds to environmental events to trigger gametogenesis and regulate fertilization; however, such knowledge remains limited for malaria parasites. Several pseudokinases are highly transcribed at the gametocyte stage and are possible multi-functional regulators controlling critical steps of the life cycle. Here we characterized one pseudokinase, termed PypPK1, inPlasmodium yoeliithat is highly expressed in schizonts and male gametocytes. Immunofluorescence assays for parasites expressing Myc-tagged PypPK1 confirmed that PypPK1 protein is expressed in schizonts and sexual stage parasites. Transgenic ΔpPK1 parasites, in which the PypPK1 gene locus was deleted by the CRISPR/Cas9 method, showed significant growth defect and reduced virulence in mice. In the blood stage, ΔpPK1 parasites were able to egress from erythrocytes similar to wild type parasites; however, erythrocyte invasion efficacy was significantly reduced. During sexual stage development, no clear changes were seen in male and female gametocytemias as well as gametocyte egress from erythrocytes; but, the number of exflagellation centers and oocysts were significantly reduced in ΔpPK1 parasites. Taken together, PypPK1 has an important role for both erythrocyte invasion and exflagellation center formation.