PTPRB

VE-PTP is a member of the classical protein tyrosine phosphatase (PTP) family. The deletion of the gene in mouse models was shown to be embryonically lethal,^[7] thus indicating that it is important for vasculogenesis and blood vessel development. In addition, it was shown to participate in adherens junctions complex and regulate vascular permeability.^[8][9] Recently, Soni et al. have shown that tyrosine phosphorylation of VE-PTP via Pyk2 kinase downstream of STIM1-induced calcium entry mediates disassembly of the endothelial adherens junctions.^[9]

VE-PTP contains an extracellular domain composed of multiple fibronectin type_III repeats, a single transmembrane segment and one intracytoplasmic catalytic domain, thus belongs to R3 receptor subtype PTPs. The extracellular region was shown to interact with the angiopoietin receptor Tie-2^[6] and with the adhesion protein VE-cadherin.^[9][10]

VE-PTP was also found to interact with Grb2 and plakoglobin through its cytoplasmatic domain.

VE-PTP was also shown through proximity ligation assay to form a complex with VEGFR2,^[11][12] which is involved in regulation of angiogenesis and vascular permeability.^[13] Activation of VEGFR2 by VEGF was shown to induce complex dissociation, leading to increased VEGFR2 phosphorylation at tyrosine sites 1175 and 951 in immortalized endothelial cells.^[11][12]

Dysregulation of PTPRB correlates with the development of a variety of tumors. PTPRB promotes metastasis of colorectal cancer cells via inducing epithelial-mesenchymal transition (EMT).^[14]