Phosphoproteomic Insights into the Metabolic Reprogramming of Cell Growth and Lipid Accumulation in Mucor...

Mucor circinelloides is a model oleaginous fungus for studying microbial lipid accumulation, yet the post-translational mechanisms coordinating growth and lipid biosynthesis remain poorly understood. Here, we present the first systematic quantitative phosphoproteomic analysis of M. circinelloides across its life cycle, encompassing spores and mycelia at 6 h, 24 h (nitrogen depletion), and 96 h. A total of 1252 phosphoproteins and 1682 phosphopeptides were identified, revealing a phosphorylation-driven transition from growth-associated processes to lipid metabolism under nitrogen limitation. Dynamic phosphorylation of key enzymes, notably ATP-citrate lyase (ACL) and Acyl-CoA synthetase (ACS), directly mediated carbon flux redirection toward fatty acid synthesis. A conserved serine-rich motif in ACL suggests an evolutionarily conserved regulatory strategy for lipid accumulation. Integration with fluxomics and proteomics reveals a hierarchical network linking signaling, enzyme phosphorylation, and metabolic reprogramming. These findings provide new insights into phosphorylation-based regulation of fungal growth and lipid biosynthesis in oleaginous fungi.