Plasma Membrane Organization and Its Impact on Growth and Development in Schizophyllum commune

Lipid rafts are dynamic microdomains within the cell membrane. They are highly enriched in sterols and sphingolipids as well as specific raft proteins. These domains act as platforms for signal transduction, membrane trafficking, protein sorting, and polarized growth (Alvarez et al., 2007). Polarized growth of the filamentous basidiomycete Schizophyllum commune requires the supply of proteins and lipids to the hyphal tip by vesicle trafficking. Crucial in establishing and maintaining polarity are the actin cytoskeleton and raft domains (Takeshita et al., 2008). Rafts contain specific proteins like stomatin and striatin. They play a role in cell signalling and signal transduction, as well as in numerous protein-protein interactions and the assembly of proteins in distinct signalling complexes. Functional analyses demonstrate that both proteins are critical regulators of fungal development. Deletion of striatin (Δstr1) results in aberrant fruiting body formation, including defects in primordia development, as well as irregular hyphal branching. Transcriptomic analyses (RNA-seq and RT-qPCR) show upregulation of developmental transcription factors and indicate a link between striatin and pheromone response signaling. Similarly, stomatin deletion alters morphology and induces expression changes in MAP kinase pathways, G protein-coupled receptors, and cytoskeleton-associated genes. Based on these findings, the ongoing project aims to further investigate the molecular mechanisms underlying raft-mediated signaling in S. commune. Future work will focus on (i) identifying additional components of lipid raft-associated protein complexes, (ii) characterizing protein–protein interactions and their dynamics using advanced imaging and biochemical approaches, and (iii) elucidating how membrane microdomains coordinate signaling pathways that control hyphal polarity and multicellular development. This work will establish a comprehensive framework for understanding membrane domain organization as a central regulatory principle in fungal growth and differentiation. Alvarez FJ, Douglas LM, Konopka JB2007.Sterol-Rich Plasma Membrane Domains in Fungi. Eukaryot Cell6:.https://doi.org/10.1128/ec.00008-07 Takeshita, N., Higashitsuji, Y., Konzack, S., & Fischer, R. (2008). Apical sterol-rich membranes are essential for localizing cell end markers that determine growth directionality in the filamentous fungus Aspergillus nidulans. Molecular Biology of the Cell, 19(1), 339–351. doi:10.1091/mbc.e07-06-0523

PhD start: 02/24/2025