In filamentous fungi, early endosomes are continuously trafficked to, and from, the growing hyphal tip by microtubule‐based motor proteins, serving as platforms for the long‐distance transport of diverse cargos including mRNA, signaling molecules, and other organelles which hitchhike on them. While the cellular machinery for early endosome motility in filamentous fungi is fairly well characterized, the broader physiological significance of this process remains less well understood. We set out to determine the importance of long‐distance early endosome trafficking in Aspergillus fumigatus , an opportunistic human pathogenic fungus that can cause devastating pulmonary infections in immunocompromised individuals. We first characterized normal early endosome motile behavior in A. fumigatus , then generated a mutant in which early endosome motility is severely perturbed through targeted deletion of the gene encoding for FtsA, one of a complex of proteins that links early endosomes to their motor proteins. Using a microfluidics‐based approach we show that contact‐induced hyphal branching behaviors are impaired in ΔftsA mutants, but that FtsA‐mediated early endosome motility is dispensable for virulence in an invertebrate infection model. Overall, our study provides new insight into early endosome motility in an important human pathogenic fungus.

中文翻译：

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烟曲霉的远距离早期内体运动在受控的微环境中促进正常的菌丝生长行为，但对于毒力却是必不可少的。

在丝状真菌中，早期的内体通过基于微管的运动蛋白不断地运至生长的菌丝尖端，并从中运出，为长途运输各种货物（包括mRNA，信号分子和搭便车的其他细胞器）提供了平台。 。虽然丝状真菌的早期内体运动的细胞机制已被很好地表征，但该过程的更广泛的生理意义仍然鲜为人知。我们着手确定烟曲霉的远距离早期内体运输的重要性，该曲霉是一种机会致病的人类致病性真菌，在免疫力低下的人中可能导致毁灭性的肺部感染。我们首先表征了烟曲霉的正常早期内体运动行为。然后，产生了一个突变体，其中通过有针对性地缺失编码FtsA的基因而严重破坏了早期内体的运动能力，FtsA是将早期内体与运动蛋白连接的蛋白质复合体之一。使用基于微流体的方法，我们显示了在ΔftsA突变体中接触诱导的菌丝分支行为受到损害，但是在无脊椎动物感染模型中FtsA介导的早期内体运动对于毒力而言是必不可少的。总的来说，我们的研究为重要的人类致病真菌中的早期内体运动提供了新的见解。