STRIPAK is a highly conserved eukaryotic signalling complex controlling a wide range of developmental processes in microorganisms as well as humans. This study uses iTRAQ-based proteomic and phosphoproteomic analyses to expand the identification of differentially phosphorylated proteins, comparing the wildtype proteome of the model fungus S. macorspora to those from three STRIPAK single- and double deletion mutants. Among the differentially phosphorylated proteins, we detected Gul1, a homolog of GUL-1 from N. crassa and SSD1 from yeast. In this study, we further provide a functional analysis of Gul1, showing it controls sexual development and hyphal morphology in a phosphorylation dependent manner.