Transcriptional regulator with a general role in all morphogenetically distinct forms of filamentous growth, namely haploid invasive growth, biofilm formation, and diploid pseudohyphal growth. May control FLO11 gene expression as part of a promoter-bound complex with FLO8 and MSS1. Interacts with FLO8 and MSS11, both morphogenetic transcription factors binding directly to the FLO11 promoter. Present with 1010 molecules/cell in log phase SD medium. Belongs to the MFG1 family.