Enables STAT family protein binding activity and protein tyrosine phosphatase activity. Involved in several processes, including hemopoiesis; negative regulation of signal transduction; and positive regulation of response to endoplasmic reticulum stress. Acts upstream of or within insulin receptor signaling pathway; negative regulation of transcription by RNA polymerase II; and protein dephosphorylation. Located in nucleus. Is expressed in several structures, including genitourinary system; heart; hemolymphoid system gland; lower jaw; and midbrain. Orthologous to human PTPN2 (protein tyrosine phosphatase non-receptor type 2). [provided by Alliance of Genome Resources, Apr 2022]