Catalytic component of the nem1-spo7 complex which acts as a phosphatase and may be required for proper nuclear membrane morphology. H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Component of the nem1-spo7 complex. Belongs to the Dullard family.