The Energy Biosciences Institute, The University of California, Berkeley, CA 94720, USA.
Plant and Microbial Biology Department, The University of California, Berkeley, CA 94720, USA.
Mol Microbiol. 2018 Jan;107(2):229-248. doi: 10.1111/mmi.13879. Epub 2017 Dec 11.
Filamentous fungi are native secretors of lignocellulolytic enzymes and are used as protein-producing factories in the industrial biotechnology sector. Despite the importance of these organisms in industry, relatively little is known about the filamentous fungal secretory pathway or how it might be manipulated for improved protein production. Here, we use Neurospora crassa as a model filamentous fungus to interrogate the requirements for trafficking of cellulase enzymes from the endoplasmic reticulum to the Golgi. We characterized the localization and interaction properties of the p24 and ERV-29 cargo adaptors, as well as their role in cellulase enzyme trafficking. We find that the two most abundantly secreted cellulases, CBH-1 and CBH-2, depend on distinct ER cargo adaptors for efficient exit from the ER. CBH-1 depends on the p24 proteins, whereas CBH-2 depends on the N. crassa homolog of yeast Erv29p. This study provides a first step in characterizing distinct trafficking pathways of lignocellulolytic enzymes in filamentous fungi.
丝状真菌是木质纤维素酶的天然分泌体，在工业生物技术领域被用作生产蛋白质的工厂。尽管这些生物在工业中非常重要，但人们对丝状真菌的分泌途径知之甚少，也不知道如何操纵它来提高蛋白质的产量。在这里，我们使用粗糙脉孢菌作为模式丝状真菌来研究纤维素酶从内质网到高尔基体的运输所需的条件。我们描述了 p24 和 ERV-29 货物衔接蛋白的定位和相互作用特性，以及它们在纤维素酶运输中的作用。我们发现，两种最丰富分泌的纤维素酶，CBH-1 和 CBH-2，需要不同的 ER 货物衔接蛋白才能有效地从 ER 中输出。CBH-1 依赖于 p24 蛋白，而 CBH-2 依赖于酵母 Erv29p 的粗糙脉孢菌同源物。这项研究为描述丝状真菌中木质纤维素酶的不同运输途径提供了第一步。
