Maturation of late Golgi cisternae into RabE(RAB11) exocytic post-Golgi carriers visualized in vivo.
Maturation of late Golgi cisternae into RabE(RAB11) exocytic post-Golgi carriers visualized in vivo.
复制标题
晚期高尔基体池成熟为 RabE(RAB11) 胞吐后高尔基体载体，在体内可视化。
DOI：
10.1091/mbc.e14-02-0710
复制
发表时间：
2014-08-15
影响因子：
3.3
通讯作者：
Peñalva MA
中科院分区：
文献类型：
--
作者：
Pantazopoulou A;Pinar M;Xiang X;Peñalva MA
使用Nidulans Ypt31/Rab11同源物Rabe作为后高尔基体身份的报告基因，可以直接观察高尔基体池到后高尔基体载体的成熟过程。以微管为基础的传送带为从顶端辐射的肌动蛋白微丝的载体提供燃料，该微丝执行胞吐作用的膜-近端运输步骤。蛋白质穿过高尔基体和离开高尔基体的机制(S)还不完全清楚。利用尼杜氏曲霉菌丝，我们发现晚期高尔基体池经历了组成的变化，逐渐失去高尔基身份，同时获得后高尔基RabERAB11身份。晚期高尔基池的这种行为与脑池成熟模型一致。Golgi RabERAB11后携带者前往顶端并在顶端堆积，表明融合是胞吐的速率限制。这些携带着动蛋白、动力蛋白和MyoEMYO5的载体，在基于微管的双向传送带上移动，将它们传递给肌动蛋白，肌动蛋白最终将胞吐集中在顶端。如果MyoEMYO5与肌动蛋白电缆结合失败，Dynein会将RabERAB11载体拖走。如果没有MyoEMYO5，微管似乎与F-肌动蛋白捕获合作，可以维持分泌。因此，尽管黑素小体的生物发生涉及溶酶体而不是高尔基体，但涉及高尔基体后携带者的丝状真菌分泌在机制上与黑素细胞树突中的黑素小体的运输非常相似。
Maturation of Golgi cisternae into post-Golgi carriers is directly visualized using the Aspergillus nidulans Ypt31/RAB11 homologue RabE as a reporter of post-Golgi identity. A microtubule-based conveyor belt fuels carriers to actin microfilaments radiating from the apex, which carry out the membrane-proximal transport step of exocytosis. The mechanism(s) by which proteins traverse and exit the Golgi are incompletely understood. Using Aspergillus nidulans hyphae, we show that late Golgi cisternae undergo changes in composition to gradually lose Golgi identity while acquiring post-Golgi RabERAB11 identity. This behavior of late Golgi cisternae is consistent with the cisternal maturation model. Post-Golgi RabERAB11 carriers travel to, and accumulate at, the apex, indicating that fusion is rate limiting for exocytosis. These carriers, which are loaded with kinesin, dynein, and MyoEMYO5, move on a microtubule-based bidirectional conveyor belt relaying them to actin, which ultimately focuses exocytosis at the apex. Dynein drags RabERAB11 carriers away if engagement of MyoEMYO5 to actin cables fails. Microtubules seemingly cooperating with F-actin capture can sustain secretion if MyoEMYO5 is absent. Thus, filamentous fungal secretion involving post-Golgi carriers is remarkably similar, mechanistically, to the transport of melanosomes in melanocyte dendrites, even though melanosome biogenesis involves lysosomes rather than Golgi.