Transcriptional regulator of the switch between 2 heritable states, the white and opaque states. These 2 cell types differ in many characteristics, including cell structure, mating competence, and virulence. Each state is heritable for many generations, and switching between states occurs stochastically, at low frequency. Antagonizes the action of WOR1, WOR2 and CZF1, and promotes the white state. In white cells, EFG1 represses WOR1 indirectly through WOR2 to maintain white cell identity. Binds target gene promoters at the EFG1 recognition sequence (EGRbox) TATGCATA. Acts as a major regulator of cell wall dynamics and plays a role in interactions with extracellular matrices. Required for TOR1-dependent cellular aggregation and adhesin expression. Required for both normoxic and hypoxic biofilm formation. Hypoxic biofilm formation is a major cause of perseverance and antifungal resistance during infections. Contributes to virulence by regulating hyphal formation and the factors that enable C.albicans to invade and injure endothelial cells. Required for the formation of thick-walled big resting spores called chlamydospores, which survive in unfavorable conditions. Mediates the expression of virulence factors SAP4, SAP5and SAP6 during infection. Involved in drug resistance by regulating the expression of ERG3. Interacts with CZF1 and FLO8. Expression is specific for the white growth phase. Down-regulation under hyphal induction depends on the presence of EFG1 itself which plays a role of autoinhibitor and the protein kinase A isoforms TPK1 and TPK2. Thr-208 is a phosphorylation target to promote hyphal induction by a subset of environmental cues. Phosphorylation at Thr-181 by the CDc28/HGC1 complex represses cell separation genes and leads to hyphal chain formation. Belongs to the EFG1/PHD1/stuA family.