Enables non-membrane spanning protein tyrosine phosphatase activity. Acts upstream of or within blastocyst formation. Located in cytoplasm and nucleus. Is expressed in several structures, including alimentary system; brain; genitourinary system; immune system; and liver and biliary system. Orthologous to human PTPN18 (protein tyrosine phosphatase non-receptor type 18). [provided by Alliance of Genome Resources, Apr 2022]