PbPP6介导滑动体GAP40蛋白去磷酸化在疟原虫动合子发育中调控机制的研究

可逆磷酸化修饰在疟原虫有性发育中起重要调控作用。申请者研究发现，伯氏疟原虫蛋白磷酸酶6（PbPP6）高表达于动合子期并与滑动体GAP40蛋白共定位。pbpp6基因敲除（∆pbpp6）或降低GAP40动合子期表达水平均可致蚊胃内卵囊形成数目显著下降。滑动体介导动合子滑行穿越蚊胃壁发育为卵囊，而磷酸化修饰影响滑动体组装和功能。申请者通过动合子期磷酸化修饰组学分析发现，pbpp6基因敲除后，GAP40磷酸化水平显著上调。Co-IP实验证实，动合子期PbPP6与GAP40相互作用。综上我们推测：PbPP6通过调控GAP40磷酸化修饰影响滑动体组装和功能，干扰疟原虫有性发育。本课题旨在分析GAP40是否为PbPP6的磷酸化底物；解析PbPP6调控GAP40磷酸化修饰对滑动体组装和动合子滑行的影响；明确PbPP6-GAP40通路在动合子发育中的调控机制。通过上述研究拟为阻断疟原虫传播提供新的分子靶标。

Reversible phosphorylation plays an essential role in sexual stage development. In previous studies, the applicant found that the Plasmodium berghei protein phosphatase 6 (PbPP6) highly expressed at ookinete stage and co-localized with glideosome GAP40 protein. pbpp6 gene knockout (∆pbpp6) or reduction of GAP40 protein expression resulted in significant decrease oocyst formation. Glideosome mediates ookinetes’ gliding motility in mosquito midgut invasion and oocysts formation, and phosphorylation modification affects glideosome formation and function. Phosphorylated proteomics analysis of ∆pbpp6 at ookinete stage showed that the phosphorylated levels of GAP40 protein were significantly increased. Co-IP assay confirmed that PbPP6 and GAP40 interact at ookinete stage. Therefore, we speculate that PbPP6 affects glideosome formation and function, and influence parasites’ sexual stage development by regulating GAP40 protein phosphorylation. In this study, we aim to clarify whether GAP40 is PbPP6’s substrate; Elucidate the molecular function of PP6 regulating GAP40 phosphorylation in glideosome formation and ookinete motility; Determine the role of PP6-GAP40 signaling pathway in ookinete development. Through this project, we will provide a new molecular target for malaria transmission blocking.