Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA.
Department of Biological Sciences, University of North Texas at Dallas, Dallas, Texas, USA.
J Neurochem. 2020 Jan;152(1):48-60. doi: 10.1111/jnc.14886. Epub 2019 Oct 27.
Phosphatidylserine (PS), a negatively charged phospholipid present predominantly at the inner leaflet of the plasma membrane, has been widely implicated in many cellular processes including membrane trafficking. Along this line, PS has been demonstrated to be important for endocytosis, however, the involved mechanisms remain uncertain. By monitoring clathrin-mediated endocytosis (CME) of single vesicles in mouse chromaffin cells using cell-attached capacitance measurements that offer millisecond time resolution, we demonstrate in the present study that the fission-pore duration is reduced by PS addition, indicating a stimulatory role of PS in regulating the dynamics of vesicle fission during CME. Furthermore, our results show that the PS-mediated effect on the fission-pore duration is Ca -dependent and abolished in the absence of synaptotagmin 1 (Syt1), implying that Syt1 is necessary for the stimulatory role of PS in vesicle fission during CME. Consistently, a Syt1 mutant with a defective PS-Syt1 interaction increases the fission-pore duration. Taken together, our study suggests that PS-Syt1 interaction may be critical in regulating fission dynamics during CME.
磷脂酰丝氨酸（PS）是一种带负电荷的磷脂，主要存在于质膜的内小叶，广泛参与包括膜运输在内的许多细胞过程。在此方面，PS 已被证明对胞吞作用很重要，然而，涉及的机制仍不确定。通过使用提供毫秒时间分辨率的细胞贴附电容测量，在本研究中我们监测了小鼠嗜铬细胞中单囊泡的网格蛋白介导的胞吞作用（CME），证明 PS 的添加缩短了裂孔持续时间，表明 PS 在调节 CME 期间囊泡裂变的动力学中起刺激作用。此外，我们的结果表明，PS 对裂孔持续时间的影响是 Ca2+依赖性的，并且在没有突触结合蛋白 1（Syt1）的情况下会被消除，这表明 Syt1 是 PS 在 CME 期间刺激囊泡裂变所必需的。一致地，具有 PS-Syt1 相互作用缺陷的 Syt1 突变体增加了裂孔持续时间。总之，我们的研究表明，PS-Syt1 相互作用可能在调节 CME 期间的裂变动力学中起关键作用。
