Overexpression of msnA reprograms metabolism to enhance recombinant protein secretion across Aspergillus species

Filamentous fungi, particularly Aspergillus species, play a crucial role in industrial biotechnology due to their exceptional protein secretion systems and robust metabolic adaptability. However, variability in heterologous protein production presents a major bottleneck. Here, we combine multi-omics analyses and synthetic biology to identify msnA as a key regulator of recombinant protein production in Aspergillus spp. Overexpression of msnA enhances secretion of diverse proteins (e.g., glycoside hydrolases, fluorescent proteins) by up to 2.8-fold in A. nidulans, A. niger, and A. oryzae, demonstrating functional conservation across Aspergillus species. Mechanistically, transcriptomic studies reveal that msnA reprograms cellular resource allocation by upregulating vesicle transport and fatty-acid degradation while downregulating secondary metabolism, thereby redirecting energy toward recombinant protein synthesis and secretion. Remarkably, the overexpression of msnA significantly improves the efficiency of recombinant protein secretion, even with lower transcriptional expression. In some species, this enhancement occurs despite a decrease in total secreted protein. Our research identifies msnA as a potential target gene for optimizing fungal cell factories, offering a framework to enhance recombinant protein production and increase the efficiency of Aspergillus-based systems in industrial applications.