Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium.
Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium.
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Copine A 调节盘基网柄菌中收缩液泡和后溶酶体的大小和胞吐作用。
DOI：
10.1002/2211-5463.12874
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发表时间：
2020
期刊：
影响因子：
2.6
通讯作者：
Damer,CynthiaK
中科院分区：
文献类型：
--
作者：
Wight,EliseM;Ide,AmberD;Damer,CynthiaK
Copines是一类以钙离子依赖方式与细胞膜结合的胞浆蛋白家族，存在于许多真核生物中，盘基网柄藻（Dictyosteoblasterdiscoideum，Dictyosteoblasterdiscoideum，Dictyosteoblasterdiscoideum）有6个copine基因（cpnA‐cpnF），缺乏cpnA的细胞（cpnA−）在胞质分裂、趋化、粘附和发育方面存在缺陷。CpnA也被证明与质膜、收缩空泡（CV）和内溶酶体途径的细胞器相关。在这里，我们使用ecpnA −细胞来研究CpnA在CV功能和内吞作用中的作用。当置于水中时，cpnA−细胞产生异常大的CV，需要更长的时间才能排出。用标记蛋白GFP‐dajumin观察CV表明，cpnA −细胞的CV较少，有时在完全排空之前重新填充。在胞吞作用试验中，cpnA−细胞通过巨胞饮作用以与亲本细胞相似的速率摄取小荧光珠。然而，cpnA−细胞比亲本细胞更早达到平台期，并且在稍后的时间点具有更少的荧光。p80抗体标记的后溶酶体（PL）表明，有更少和更小的PL inpnA −细胞。在右旋糖酐脉冲追踪实验中，PL的数量在pnA −细胞中更早达到峰值，与亲本细胞相比，PL没有变得那么大，消失得更快。PLs incpnA−细胞也显示有更多的肌动蛋白涂层，这表明CpnA可能在PL膜上的肌动蛋白丝分解中发挥作用。总体而言，这些结果表明，CpnA参与CV大小和排出的调节，以及PL的成熟、大小和胞吐。
Copines are a family of cytosolic proteins that associate with membranes in a calcium‐dependent manner and are found in many eukaryotic organisms.Dictyostelium discoideumhas six copine genes (cpnA‐cpnF), and cells lackingcpnA(cpnA−) have defects in cytokinesis, chemotaxis, adhesion, and development. CpnA has also been shown to associate with the plasma membrane, contractile vacuoles (CV), and organelles of the endolysosomal pathway. Here, we usecpnA−cells to investigate the role of CpnA in CV function and endocytosis. When placed in water,cpnA−cells made abnormally large CVs that took longer to expel. Visualization of CVs with the marker protein GFP‐dajumin indicated thatcpnA−cells had fewer CVs that sometimes refilled before complete emptying. In endocytosis assays,cpnA−cells took up small fluorescent beads by macropinocytosis at rates similar to parental cells. However,cpnA−cells reached a plateau sooner than parental cells and had less fluorescence at later time points. p80 antibody labeling of postlysosomes (PL) indicated that there were fewer and smaller PLs incpnA−cells. In dextran pulse‐chase experiments, the number of PLs peaked earlier incpnA−cells, and the PLs did not become as large and disappeared sooner as compared to parental cells. PLs incpnA−cells were also shown to have more actin coats, suggesting CpnA may play a role in actin filament disassembly on PL membranes. Overall, these results indicate that CpnA is involved in the regulation of CV size and expulsion, and the maturation, size, and exocytosis of PLs.