Shi Yang, Wan Lin, Jiao Mengmeng, Zhong Chuan-Qi, Cui Huiting, Yuan Jing
State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China.
Department of Infectious Disease, Xiang'an Hospital of Xiamen University, School of Medicine, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China.
Nat Commun. 2025 Mar 6;16(1):2259. doi: 10.1038/s41467-025-57517-y.
cGMP signal-activated ookinete gliding is essential for mosquito midgut infection of Plasmodium in malaria transmission. During ookinete development, cGMP synthesizer GCβ polarizes to a unique localization "ookinete extrados site" (OES) until ookinete maturation and activates cGMP signaling for initiating parasite motility. However, the mechanism underlying GCβ translocation from cytosol to OES remains elusive. Here, we use protein proximity labeling to search the GCβ-interacting proteins in ookinetes of the rodent malaria parasite P. yoelii, and find the top hit Sir2A, a NAD-dependent sirtuin family deacetylase. Sir2A interacts with GCβ throughout ookinete development. In mature ookinetes, Sir2A co-localizes with GCβ at OES in a mutually dependent manner. Parasites lacking Sir2A lose GCβ localization at OES, ookinete gliding, and mosquito infection, phenocopying GCβ deficiency. GCβ is acetylated at gametocytes but is deacetylated by Sir2A for OES localization at mature ookinetes. We further demonstrate that the level of NAD, an essential co-substrate for sirtuin, increases during the ookinete development. NAD at its maximal level in mature ookinetes promotes Sir2A-catalyzed GCβ deacetylation, ensuring GCβ localization at OES. This study highlights the spatiotemporal coordination of cytosolic NAD level and NAD-dependent Sir2A in regulating GCβ deacetylation and dynamic localization for Plasmodium ookinete gliding.
cGMP信号激活的动合子滑行对于疟原虫在疟疾传播过程中感染蚊子中肠至关重要。在动合子发育过程中，cGMP合成酶GCβ极化至一个独特的定位“动合子外弧位点”（OES），直至动合子成熟，并激活cGMP信号以启动寄生虫运动。然而，GCβ从胞质溶胶转运至OES的潜在机制仍不清楚。在这里，我们使用蛋白质邻近标记法在啮齿动物疟原虫约氏疟原虫的动合子中寻找与GCβ相互作用的蛋白质，并发现排名第一的是Sir2A，一种NAD依赖性的沉默调节蛋白家族脱乙酰酶。在整个动合子发育过程中，Sir2A都与GCβ相互作用。在成熟动合子中，Sir2A与GCβ以相互依赖的方式共定位于OES。缺乏Sir2A的寄生虫在OES处失去GCβ定位、动合子滑行以及蚊子感染能力，表现出与GCβ缺陷相似的表型。GCβ在配子体阶段被乙酰化，但在成熟动合子中被Sir2A去乙酰化以定位于OES。我们进一步证明，作为沉默调节蛋白的必需辅助底物，NAD的水平在动合子发育过程中升高。成熟动合子中处于最高水平的NAD促进Sir2A催化的GCβ去乙酰化，确保GCβ定位于OES。这项研究突出了胞质NAD水平和NAD依赖性Sir2A在调节疟原虫动合子滑行的GCβ去乙酰化和动态定位中的时空协调作用。
