Endosomal transport of septin mRNAs and encoded proteins in the phytopathogen Ustilago maydis

内体转运细胞大分子，如脂质和蛋白质。这些分子载体主要从其他膜隔室接收它们的货物。特别是在高度极化的细胞如神经元和真菌菌丝中，内体沿着微管穿梭，并在长距离运输中执行复杂的功能。越来越多的证据表明，这些膜载体也转运mRNA作为非常规货物。然而，人们对这种内体mRNA转运的精确分子功能知之甚少。在玉米黑粉菌（Ustilagomaydis）中，我们最近发现Septin mRNA和蛋白质在内体上的转运对于Septin丝在菌丝生长极的正确形成是重要的。我们提出了一种新的细胞生物学机制，即内体偶联翻译，这是重要的内体装载septins的正确组装和运输。在这里，我们挑战这一假设，通过调查本地翻译在体内。此外，我们将解决是否所有四个septins共定位的内涵体以及在细丝和测试是否这是依赖于mRNA的运输。因此，我们将获得新的见解的mRNA运输，膜运输和septin生物学的分子连接。

Endosomes transport cellular macromolecules such as lipids and proteins. These molecular carriers mainly receive their cargo from other membrane compartments. Particularly in highly polarised cells like neurons and fungal hyphae, endosomes shuttle along microtubules and carry out sophisticated functions in long-distance transport. Evidence is accumulating that these membranous carriers also transport mRNAs as unconventional cargo. However, little is known about the precise molecular function of this endosomal mRNA transport. In the phytopathogen Ustilago maydis we recently discovered that septin mRNA and protein transport on endosomes is important for correct formation of septin filaments at the hyphal growth pole. We propose a novel cell biological mechanism, namely endosome-coupled translation, which is important for loading of endosomes with septins for their correct assembly and transport. Here, we challenge this hypothesis by investigating local translation in vivo. Moreover, we will address whether all four septins co-localise on endosomes as well as in filaments and test whether this is dependent of mRNA transport. Thus, we will gain new insights in the molecular connection of mRNA transport, membrane trafficking and septin biology.