Protein tyrosine phosphatase that negatively regulates oligodendrocyte precursor proliferation in the embryonic spinal cord. Required for normal differentiation of the precursor cells into mature, fully myelinating oligodendrocytes. May play a role in protecting oligondendrocytes against apoptosis. May play a role in the establishment of contextual memory, probably via the dephosphorylation of proteins that are part of important signaling cascades (By similarity). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate The carbonic-anhydrase like domain interacts with CNTN1 (contactin) (PubMed:20133774). Interacts with PTN (PubMed:16814777). Interaction with PTN promotes formation of homooligomers; oligomerization impairs phosphatase activity (By similarity). Interacts (via chondroitin sulfate chains) with MDK (via C-terminal); this interaction is inhibited by PTN; this interaction promotes neuronal migration (By similarity). A secreted form is apparently generated by shedding of the extracellular domain. Specifically expressed in the central nervous system, where it is localized in the Purkinje cell layer of the cerebellum, the dentate gyrus, and the subependymal layer of the anterior horn of the lateral ventricle. Developmentally regulated in the brain. Belongs to the protein-tyrosine phosphatase family. Receptor class 5 subfamily. Was termed (PubMed:8387522 and PubMed:2170109) RPTPase beta. The human genome was initially thought to contain 2 genes for PTPRZ: PTPRZ1 (on chr 7) and PTPRZ2 (on chr 1). However, PTPRZ2 probably does not exist and corresponds to PTPRZ1. Contaminating sequence. The N-terminus may be contaminated with vector sequence.