The 3-phosphoinositide-dependent protein kinase 1 is an essential upstream activator of protein kinase A in malaria parasites.
The 3-phosphoinositide-dependent protein kinase 1 is an essential upstream activator of protein kinase A in malaria parasites.
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DOI：
10.1371/journal.pbio.3001483
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发表时间：
2021-12
期刊：
影响因子：
9.8
通讯作者：
Voss TS
中科院分区：
文献类型：
--
作者：
Hitz E;Wiedemar N;Passecker A;Graça BAS;Scheurer C;Wittlin S;Brancucci NMB;Vakonakis I;Mäser P;Voss TS
环磷酸腺苷(CAMP)依赖的蛋白激酶A(PKA)信号通路对恶性疟原虫血液期寄生虫的增殖至关重要。然而，对PfPKAc催化亚单位活性的调节机制还只有部分了解，PfPKAc在配子细胞中的功能还没有被研究过，配子细胞是疟疾传播所必需的有性血期形式。通过对一个条件性PfPKAc基因敲除(CKD)突变体的研究，我们证实了PfPKAc在裂殖子入侵红细胞中的重要作用，并表明PfPKAc参与调节配子的变形能力。我们进一步证明了PfPKAc的过度表达是致命的，并在分裂的早期阶段杀死了寄生虫。值得注意的是，选择耐受PfPKAc表达水平增加的寄生虫突变株的全基因组测序(WGS)发现了编码寄生虫3-磷酸肌醇依赖蛋白激酶-1(PfPDK1)的同源基因的错义突变。利用靶向突变，我们证明了PfPDK1是激活PfPKAc所必需的，而PfPKAc激活环中的T189是这一过程中关键的靶残基。总之，我们的结果证实了严格调控PfPKA信号对寄生虫生存的重要性，并暗示PfPDK1在这一途径和潜在的新药靶点中扮演着关键的上游调节因子的角色。CAMP依赖的蛋白激酶A(PKA)信号通路对恶性疟原虫血液期寄生虫的增殖至关重要。条件表达和全基因组测序的结合表明，3-磷脂酰肌醇依赖的蛋白激酶-1(PDK1)在该途径中起着关键的上游调节作用，是一个潜在的新药靶点。
Cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) signalling is essential for the proliferation of Plasmodium falciparum malaria blood stage parasites. The mechanisms regulating the activity of the catalytic subunit PfPKAc, however, are only partially understood, and PfPKAc function has not been investigated in gametocytes, the sexual blood stage forms that are essential for malaria transmission. By studying a conditional PfPKAc knockdown (cKD) mutant, we confirm the essential role for PfPKAc in erythrocyte invasion by merozoites and show that PfPKAc is involved in regulating gametocyte deformability. We furthermore demonstrate that overexpression of PfPKAc is lethal and kills parasites at the early phase of schizogony. Strikingly, whole genome sequencing (WGS) of parasite mutants selected to tolerate increased PfPKAc expression levels identified missense mutations exclusively in the gene encoding the parasite orthologue of 3-phosphoinositide–dependent protein kinase-1 (PfPDK1). Using targeted mutagenesis, we demonstrate that PfPDK1 is required to activate PfPKAc and that T189 in the PfPKAc activation loop is the crucial target residue in this process. In summary, our results corroborate the importance of tight regulation of PfPKA signalling for parasite survival and imply that PfPDK1 acts as a crucial upstream regulator in this pathway and potential new drug target. cAMP-dependent protein kinase A (PKA) signalling is essential for the proliferation of Plasmodium falciparum malaria blood stage parasites. A combination of conditional expression and whole-genome sequencing reveals that 3-phosphoinositide-dependent protein kinase-1 (PDK1) acts as a crucial upstream regulator in this pathway and is a potential new drug target.