Department of Cell Biology, Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
Electron Microscopy Core Facility, Heidelberg University, Im Neuenheimer Feld 345, 69120 Heidelberg, Germany.
J Cell Sci. 2021 Oct 15;134(20). doi: 10.1242/jcs.258807. Epub 2021 Oct 25.
The trans-Golgi network/early endosome (TGN/EE) serves as the central hub in which exocytic and endocytic trafficking pathways converge and specificity of cargo routing needs to be achieved. Acidification is a hallmark of the TGN/EE and is maintained by the vacuolar H+-ATPase (V-ATPase) with support of proton-coupled antiporters. We show here that ClCd and ClCf, two distantly related members of the Arabidopsis Cl- channel (ClC) family, colocalize in the TGN/EE, where they act redundantly, and are essential for male gametophyte development. Combining an inducible knockdown approach and in vivo pH measurements, we show here that reduced ClC activity does not affect pH in the TGN/EE but causes hyperacidification of trans-Golgi cisternae. Taken together, our results show that ClC-mediated anion transport into the TGN/EE is essential and affects spatiotemporal aspects of TGN/EE maturation as well as its functional separation from the Golgi stack.
反式高尔基体网络/早期内体（TGN/EE）是胞吐和胞吞运输途径汇聚的中心枢纽，需要实现货物运输的特异性。酸化是 TGN/EE 的标志，由液泡 H+-ATP 酶（V-ATPase）维持，质子偶联转运蛋白提供支持。我们在这里表明，拟南芥 Cl-通道（ClC）家族中两个远缘相关的成员 ClCd 和 ClCf 在 TGN/EE 中共定位，它们在那里发挥冗余作用，对于雄性配子体发育是必不可少的。结合诱导性敲低方法和体内 pH 测量，我们在这里表明，降低 ClC 活性不会影响 TGN/EE 中的 pH，但会导致反式高尔基体潴腔的过度酸化。总之，我们的结果表明，ClC 介导的阴离子向 TGN/EE 的运输是必不可少的，并且影响 TGN/EE 成熟的时空方面以及其与高尔基体堆叠的功能分离。
