Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany.
ZMBH, University of Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
J Cell Sci. 2020 Feb 13;133(3):jcs237982. doi: 10.1242/jcs.237982.
Owing to the local enrichment of factors that influence its dynamics and organization, the actin cytoskeleton displays different shapes and functions within the same cell. In yeast cells, post-Golgi vesicles ride on long actin cables to the bud tip. The proteins Boi1 and Boi2 (Boi1/2) participate in tethering and docking these vesicles to the plasma membrane. Here, we show in that Boi1/2 also recruit nucleation and elongation factors to form actin filaments at sites of exocytosis. Disrupting the connection between Boi1/2 and the nucleation factor Bud6 impairs filament formation, reduces the directed movement of the vesicles to the tip and shortens the vesicles' tethering time at the cortex. Transplanting Boi1 from the bud tip to the peroxisomal membrane partially redirects the actin cytoskeleton and the vesicular flow towards the peroxisome, and creates an alternative, rudimentary vesicle-docking zone. We conclude that Boi1/2, through interactions with Bud6 and Bni1, induce the formation of a cortical actin structure that receives and aligns incoming vesicles before fusion with the membrane.
由于影响其动态和组织的局部因素的丰富，细胞中的肌动蛋白细胞骨架呈现出不同的形状和功能。在酵母细胞中，高尔基体后期的囊泡沿着长的肌动蛋白电缆运输到芽尖。Boi1 和 Boi2（Boi1/2）蛋白参与将这些囊泡与质膜锚定和对接。在这里，我们在 中表明，Boi1/2 还招募成核和延伸因子在胞吐部位形成肌动蛋白丝。破坏 Boi1/2 与成核因子 Bud6 之间的连接会损害丝状体的形成，减少囊泡向芽尖的定向运动，并缩短囊泡在皮质的锚定时间。将芽尖的 Boi1 移植到过氧化物酶体膜上，部分重新定向了肌动蛋白细胞骨架和囊泡流，形成了一个替代的、原始的囊泡停靠区。我们得出结论，Boi1/2 通过与 Bud6 和 Bni1 的相互作用，诱导形成了一个皮质肌动蛋白结构，该结构在与膜融合之前接收和排列进入的囊泡。
