Department of Microbiology and Molecular Medicine, University of Geneva CMU, Geneva, Switzerland.
Cell Microbiol. 2019 May;21(5):e13018. doi: 10.1111/cmi.13018. Epub 2019 Mar 18.
One of the hallmarks of the parasitic phylum of Apicomplexa is the presence of highly specialised, apical secretory organelles, called the micronemes and rhoptries that play critical roles in ensuring survival and dissemination. Upon exocytosis, the micronemes release adhesin complexes, perforins, and proteases that are crucially implicated in egress from infected cells, gliding motility, migration across biological barriers, and host cell invasion. Recent studies on Toxoplasma gondii and Plasmodium species have shed more light on the signalling events and the machinery that trigger microneme secretion. Intracellular cyclic nucleotides, calcium level, and phosphatidic acid act as key mediators of microneme exocytosis, and several downstream effectors have been identified. Here, we review the key steps of microneme biogenesis and exocytosis, summarising the still fractal knowledge at the molecular level regarding the fusion event with the parasite plasma membrane.
顶复门寄生虫的一个显著特征是存在高度特化的顶端分泌细胞器，称为微线体和棒状体，它们在确保生存和传播方面起着关键作用。在胞吐作用时，微线体释放出黏附复合物、穿孔素和蛋白酶，这些物质对于寄生虫从感染细胞中逸出、滑行运动、穿过生物屏障迁移以及宿主细胞入侵至关重要。最近对刚地弓形虫和疟原虫的研究进一步阐明了触发微线体分泌的信号事件和机制。细胞内环核苷酸、钙离子水平和磷脂酸作为微线体胞吐的关键介质，已经鉴定出几种下游效应物。在这里，我们回顾了微线体生物发生和胞吐的关键步骤，总结了分子水平上关于与寄生虫质膜融合事件的仍然零散的知识。
