Secreted proteins are key players in fungal physiology and cell protection against external stressing agents and antifungals. Oak stress‐induced protein 1 (OSIP1) is a fungal‐specific protein with unknown function. By using Podospora anserina and Phanerochaete chrysosporium as models, we combined both in vivo functional approaches and biophysical characterization of OSIP1 recombinant protein. The P. anserina OSIP1^Δ mutant showed an increased sensitivity to the antifungal caspofungin compared to the wild type. This correlated with the production of a weakened extracellular exopolysaccharide/protein matrix (ECM). Since the recombinant OSIP1 from P. chrysosporium self‐assembled as fibers and was capable of gelation, it is likely that OSIP1 is linked to ECM formation that acts as a physical barrier preventing drug toxicity. Moreover, compared to the wild type, the OSIP1^Δ mutant was more sensitive to oak extractives including chaotropic phenols and benzenes. It exhibited a strongly modified secretome pattern and an increased production of proteins associated to the cell‐wall integrity signalling pathway, when grown on oak sawdust. This demonstrates that OSIP1 has also an important role in fungal resistance to extractive‐induced stress.

中文翻译：

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OSIP1 是一种自组装 DUF3129 蛋白，用于保护真菌细胞免受毒素和压力源的侵害

分泌蛋白是真菌生理学和细胞保护免受外部压力剂和抗真菌剂的关键因素。橡树应激诱导蛋白 1 (OSIP1) 是一种功能未知的真菌特异性蛋白。通过使用Podospora anserina和Phanerochaete chrysosporium作为模型，我们结合了OSIP1 重组蛋白的体内功能方法和生物物理表征。的鹅绒委陵菜OSIP1 ^Δ突变体显示与野生型的抗真菌卡泊芬净的敏感性增加。这与减弱的细胞外多糖/蛋白质基质 (ECM) 的产生有关。由于来自P. chrysosporium的重组 OSIP1OSIP1 自组装成纤维并能够凝胶化，很可能 OSIP1 与 ECM 形成有关，ECM 充当防止药物毒性的物理屏障。此外，与野生型相比，OSIP1 ^Δ突变体对橡木提取物（包括离液酚和苯）更敏感。当在橡木锯末上生长时，它表现出强烈修饰的分泌组模式和与细胞壁完整性信号通路相关的蛋白质产量增加。这表明 OSIP1 在真菌对提取诱导的压力的抗性中也具有重要作用。