Protein tyrosine phosphatase that acts as a repressor of the yeast-hyphal switch. Plays an important role in virulence. Negatively regulates CST20-HST7-CEK1-CPH1 filamentous growth pathway. Represses hyphal genes such as SAP4, SA5, SAP6, and HYR1, by acting through a CEK1-independent mechanism. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Derepresses filamentous growth and decreases virulence and resistance to cell wall and osmotic stress. Belongs to the protein-tyrosine phosphatase family. Non-receptor class dual specificity subfamily.