Receptor-type tyrosine-protein phosphatase O (PTPRO)

Receptor-type tyrosine-protein phosphatase O (PTPRO) is a transmembrane enzyme encoded by the PTPRO gene and classified within the R3 family of receptor-like protein tyrosine phosphatases. It features a large extracellular region with multiple fibronectin-like repeats, a single transmembrane domain, and a cytoplasmic domain with phosphatase activity responsible for dephosphorylating specific tyrosine residues on target proteins. PTPRO is expressed mainly in kidney glomerular epithelial cells, neurons, and immune cells, while its truncated isoform (PTPROt) predominates in hematopoietic cells (B cells, T cells, macrophages, osteoclasts). PTPRO modulates critical cellular processes, including cell growth, differentiation, proliferation, apoptosis, immune responses, and synapse formation. It functions as a tumor suppressor in several cancers, often downregulated by promoter methylation. PTPRO participates in signal transduction cascades by regulating phosphorylation of key proteins (e.g., Syk, Lyn, Lck, JAK2/STAT3) and maintaining proper immune cell differentiation and anti-tumor responses. Its full biological and therapeutic significance is still under active investigation, but it is recognized as a potential target for epigenetic therapy and cancer immunomodulation

Other names

PTPROGlomerular epithelial protein 1 (GLEPP1)Protein tyrosine phosphatase receptor type OPTPROt (refers to a truncated, tissue-specific isoform present mainly in hematopoietic cells)

Drugs theoretically targeting PTPRO would most likely act by modulating its phosphatase activity—either inhibiting or enhancing the dephosphorylation of substrates involved in signaling pathways (e.g., BCR, TCR, JAK/STAT)