Institute for Microbiology, Cluster of Excellence on Plant Sciences Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
EMBO Rep. 2014 Jan;15(1):94-102. doi: 10.1002/embr.201338037. Epub 2013 Dec 15.
Endosomes transport lipids and proteins over long distances by shuttling along microtubules. They also carry mRNAs on their surface, but the precise molecular function of this trafficking process is unknown. By live cell imaging of polarized fungal hyphae, we show microtubule-dependent transport of septin mRNA and encoded septin protein on the same shuttling endosomes. Consistent with the hypothesis that septin mRNA is translated on endosomes, the accumulation of septin protein on endosomes requires the recruitment of septin mRNA. Furthermore, ribosomal proteins co-localise with shuttling endosomes, but only if mRNA is present. Importantly, endosomal trafficking is essential for an efficient delivery of septin protein to filaments at growth poles, a process necessary to establish unipolar growth. Thus, we propose that local mRNA translation loads endosomes with septins for assembly and efficient delivery to septin filaments.
内体通过沿着微管穿梭来远距离运输脂质和蛋白质。它们表面还携带 mRNA，但这种运输过程的确切分子功能尚不清楚。通过对极化真菌菌丝的活细胞成像，我们显示了 septin mRNA 和编码 septin 蛋白在同一穿梭内体上的微管依赖性运输。与 septin mRNA 在内体上翻译的假设一致，septin 蛋白在内体上的积累需要 septin mRNA 的募集。此外，核糖体蛋白与穿梭内体共定位，但前提是存在 mRNA。重要的是，内体运输对于 septin 蛋白有效递送到生长极的丝状体至关重要，这是建立单极生长所必需的。因此，我们提出局部 mRNA 翻译将 septin 加载到内体上，用于组装和有效递送到 septin 丝状体。
