receptor-type tyrosine-protein phosphatase U; R-PTP-U; pancreatic carcinoma phosphatase 2; PCP-2; protein-tyrosine phosphatase J; PTP-J; hPTP-J; protein-tyrosine phosphatase pi; PTP pi; protein-tyrosine phosphatase receptor omicron; PTP-RO; receptor-type protein-tyrosine phosphatase psi; R-PTP-psi (PTPRU, FMI, PCP2, PTPRO)

Function

• tyrosine-protein phosphatase which dephosphorylates CTNNB1
• regulates CTNNB1 function both in cell adhesion & signaling
• may function in cell proliferation & migration & play a role in maintenance of epithelial integrity
• may play a role in megakaryocytopoiesis
• the extracellular domain is proteolytically processed through cleavage within the fibronectin type-III 4 domain (putative)
• beside the 190 kD full-length protein, proteolytic products of 100 kD, 80 kD & 73 kD are observed
• phosphorylated on Tyr upon activation of KIT with stem cell factor (SCF)
• the 73 kD proteolytic product is not phosphorylated
• forms homooligomeric complexes which mediate cell homotypic adhesion (probable)
• interacts (via the cytoplasmic juxtamembrane domain) with CTNNB1
• may mediate interaction with cadherin/catenin adhesion complex
• interacts with KIT
• may interact with AP3B1

protein tyrosine phosphate + H2O = protein tyrosine + phosphate

Structure

• N-glycosylated
• belongs to the protein-tyrosine phosphatase family receptor class 2B subfamily
• contains 4 fibronectin F3 modules
• contains 1 Ig-like C2-type domain
• contains 1 MAM domain
• contains 2 tyrosine-protein phosphatase domains

Compartment

• cell junction, cell membrane
• single-pass type 1 membrane protein

Alternative splicing

named isoforms=4

Expression

• high expression in brain, pancreas, & skeletal muscle
• less expression in colon, kidney, liver, stomach, & uterus
• not expressed in placenta & spleen
• also detected in heart, prostate, lung, thymus, testis & ovary
• expressed througout the brain
• expressed by hematopoietic stem cells
• expressed in fetal brain, lung & kidney
• induced by upon cell contact (at protein level)
• down-regulated by phorbol ester (at protein level) & Ca+2 ionophore
• up-regulated by phorbol ester in megakaryocytic cells

More general terms

• tyrosine phosphatase, receptor type
• receptor
• glycoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=10076
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:10076
• OMIM: https://mirror.omim.org/entry/602454
• UniProt: http://www.uniprot.org/uniprot/Q92729.html